Sudan Academy of Sciences
Governmental University for Postgraduate Studies
I
Comparison between INAA and ICP-OES: Analysis of Sudanese
Medicinal PlantsA thesis submitted in partial fulfillment of requirements for the degree of
Master in nuclear sciences & technology
July 2014
ByElsadig Abdelmoniem Sheikhaldin
B.Sc. of Mathematics and Physics
University of Khartoum
Supervisor
Dr. Ammar M Ebrahim
Sudan Atomic Energy Commission
Sudan Academy of Sciences (SAS)
Governmental University for Postgraduate Studies
Atomic Energy Council
Comparison between INAA and ICP-OES: Analysis of Sudanese
Medicinal Plants
A thesis submitted in partial fulfillment of requirements for the degree of
Master in nuclear sciences & technology
By
Elsadig Abdelmoniem Sheikhaldin Mohammed
B.Sc. of Mathematics and Physics
University of Khartoum
Examination Committee
Title Name SignatureSupervisor Dr Ammar M Ebrahim s /
- L . . . . y . . . .
External examiner Dr Abubakr Mustafa Idriss, - • I
r ^ r * V ^ J
>•
July 2014
List of contents
Page
Dedication
Acknowledgements n
Abbreviations m
Abstract IV
Arabic Abstract ; Vj 1 i p *List of hgures 1 VI1
---------------- ....... ................ ...........—W
List of'TablesI1|
1 VIIii
j Chapter One: Introduction1
lij
i1. Introduction ; ilLI. Medicinal plants ■ ,i\
1.2. Historical roots of medicine in Sudan .ii1.2.1. Traditional Sudanese medicine
i
1.2.2. Overview of medicinal plants in Sudan \ n ! P
L
1.3. Importance of trace elements i— 1------------------------
1.2.1. Chromium ! 4IrI
1.2.2. Copper 14
1.2.3. Iron ! 5
1.2.4. Magnesium
1.2.5. Zinc\--------------------------1
! S1
1.2.6. Calcium 6l!L
1.2.7. Potassium | 6|i
1.2.8. Manganese 6l
1.2.9. CobaltJ
7' ' im ' ' —----1 1 " 1
1.2.10. Strontium 7
1.3. Role of trace elements in medicinal plants nl
i _ . . .
1.5. Instrumentation 8
I1.5.1 Instrumental Neutron Activation Analysis (INAA)
1.5.1.1. Basis principles
8! 9
1.5.1.2 INAA how does it work?
15.1.3. Neutrons sources
; | 0; .__
t ^j
1.5.2 The general equation of neutron activation !41.5.3 Types of standardization 16
1.5.3.1 The ko-comparator method1
17
1.5.3.2 Applications, Advantages and Limitations of NAA I i ni /— .—* i
1.5.4 Inductively Coupled Plasma-Atomic Emission Spectroscopy (1CP-AES)
Chapter Two: M aterial and M ethods
2 Material and Methods !1 ^ »
2.1 Sample collection ! 24. _____ 1
2.2 Sample drying and homogenizingr •
j 241j ____ _
2.3 1CP-OES measurement ' A 1III
2.3.1 Sample preparation 24
2.3.2 Sample analysis 26I
2.4 INAA measurements
2.4.1 Sample preparation
! Ni
jii
2.5.2 Sample irradiations and measurements 2 6
Chapter Three: Results and Discussion i_____1__
3. Results and Discussion 281
3.1. Quality control ........... f--------------------i A Q 1 O1f
3.2. Comparison of INAA and 1CP-OES results\ ----- ----------------- ’1 n
s ^
\» ...... .....■■ ■—---— • ■
3.3. Conclusions 38ii
Chapter Four: References !j1i
— --------------------------------.
4. References 39
(Dedication
To my beloved parents
To my aunt A watif
To my brothers and sisters
To my close friend Ahmed Hamed
To all o f them...1 dedicate this work
Elsadig
I
Acknowledgments
Foremost and ultimate thanks to Allah. My deepest and sincerely thank to my supervisor Dr.
Ammar M. Ebrahim for his guidance, understanding and patience throughout this study.
This work was done with the help of the staff at the Research Unit of Analytical BioGeo
Chemistry and the financial support of Helmholtz Center Munich - German Research Centre for
Environ- mental Health, Neuherberg-Germany. The practical work at the reactor is done with the
support and understanding of the staff of National ETiergy Center of Nuclear Science and
Technology-Morocco and the financial support award of the International Atomic Energy
Agency (IAEA). Thanks are also due to Dr. Saif Aldin M Babikir for a fruitful cooperation and
for his willingness to respond to my inquiries.
II
Abbreviations
f * - -
Abbreviation
ATP
Name
Adenosine triphosphate
CRM
DON A A|
Certified Reference Material
Delayed Gamma-rav Neutron Activation Analysis+ / w/ w'
Gil1!'
Glucose Tolerance Factor
! HPGE High Purity Germanium1i
. .............. . _____ _________L_ _ . . . . . . . . . . . . . . ... ____ _______________ . . . . . . . . . . .
: KT-Ol s
IN A A
Inductively Coupled Plasma-Optical Emission Spectroscopy
Instrumental Neutron Activation Analysis
PGNAA
: PMT*
Prompt Gamma-rav Neutron Activation Analysis
Photo Multiplier I’ube
SD Standard Deviation
SRM
WHO1
Standard Reference Material
World Health Oruanization
WT%1
Weight percent
r ^
Abstract
The aim of this study was to provide elemental concentrations in medicinal plants and mainly to
compare the two different determination methods (INAA and ICP-OES after wet digestion)
Elemental analysis of 14 Sudanese medicinal plants was carried out using INAA and ICP-OES
techniques. The selection of reported elements was done according to the intersection of
elements determined by both techniques. This intersecting element list contained Ca. K. Fe. Mn.
Mg, Sr, Zn, Cu, Co and Cr.
INAA correlated well with ICP-OES measurements of the same plants as long as concentrations2
were sufficiently above LoQ. Correlation coefficients (R ) in this case is close to 1. Generally.
INAA results tended to be higher compared to ICP-OES. The performance and possible sources
of errors of both techniques was discussed also with respect to measurements of certified
reference materials. INAA provided the advantage of having both, faster and non-destructive
sample preparation than ICP-OES. Therefore, INAA may be a technique of choice for Ca. K, Zn
and Mg elements specifically when samples are needed for further investigations. Regarding the
low concentrations e.g. for Cr, Ni or Cu, ICP-OES is the superior technique over INAA due to
the sufficiently low limits of determination and thus gaining more detectable results at low
concentrations.
I V
Jilajll AjjLLaU ( i l l i j -‘L nU l ClAjUill i Cj Ujc- ^ 0jJ>i3l jj^-saUxJl j J l ojiA >■ Og'i
4_ilc. !$,Li)j I *4 ) ( IC P - O E S ) ^ ! ^ ' L . j ^ b 4JjS-Jl aMJI Abbb* J ( IN A A ) ^ iy ~ ^ - -e b b
f ajiwillSll (jx i ^ 4»uAjLa]l 4j )lLd CLlgj. Amj uc' \\\ \j<A 1 j
OljUill Ljlilfr (j-iiil ICP-OES 4-kJJj fjSlb lAUk Ualfijl INAA 4-kujlJh? l&dc. J^x^ull
^ / f a
U*Jl j£\ JJ« ** * ! JaJjullijLj (Jjlaall ljUu (jl # jA-eaUxjI L-lic-V -lauu all <o 1.1. <JJ )ii JaLiijV , 3-aljtx 4<u3 Clul£ j
4_i3ljJaA J j j j l a ^jC> l^jlc- (Jj^a^Ldll 0jUull 4 jjlL dJl .lie- £-»Ja3 * u-ilc-V lk_£-lc'l J-i^' j J v—Ll
4 LdjiMJ'L!V b
JX ALbbll Abiill U jL u c I jL w b l]J U 4.1c. I b e ib liu Jl c i ib l ^ J e j A ^ ^ J b I C P - O E S J t IN A A A ijjia b jjx b
ja ba.b. bUliA - ‘'■~'r- 1 . ^ ** blljllj r* 3}.' ‘J ~1T 4l ; j ; ’1* -4l . ■ i —Li' J )l-» i
. ** it w+\\ \r„ q fl Vi'
41J INAA ( jic J j i b I C P - O E S u ' ^ <_>4ajJlj (JSbJl , _>-=>be J ib A ^ b b b il JySI jb b ^ 1 3 L b j b b e
Ab j 2SI j Aj’i j8%. l^xbbj J jSI J i l l lia> A_Joibbll jijill w""'1 4 ^ j b b
V
List of Figures
Paget.........
11Figure 1.1 Diagram illustrating the process of neutron capture by a target nucleus followed by the emission of gamma rays
Figure 1.2 Flow chart for a gamma-ray spectroscopy system 13|
21r
Figure 1.3 Schematic representation of a radial Inductively coupled plasma optical emission spectroscopy (ICP-OES)
Figure 1.4L
The excitation, relaxation and subsequent emission of light from electrons,
21
Figure 3.1 IN A A SRM ] 547 relative error % ! - ]
I Figure 3.2 ICP-OES ERM-CD 281 relative error %T
31J_____ . . . ,
Figure 3.3|
ICP-OES ERM-BB 150 relative error % N|
S i
[ j
Figure 3.4 Plant calcium contents measured by INAA and ICP-OES 35r
i
Figure 3.5 Plant potassium contents measured by INAA and ICP-OES j 3^
Figure 3.6J!
Plant zinc contents measured by INAA and ICP-OES 36 jj•
: Figure 3.7 Plant manganese contents measured by INAA and ICP-OES ! 37
Figure 3.81
• 1
Plant magnesium contents measured by INAA and ICP-OES j 37
Figure 3.9f1b . . .
Plant iron contents measured by INAA and ICP-OES 371
i1
Figure 3.10Jti
Plant cobalt contents measured by INAA and ICP-OES 38 ;j1i
Figure 3.11- ' ‘ ‘ 1 ---------------" -------------------- — — — ------------ - ---------------- - --- ----------------------- !
Plant chromium contents measured by INAA and ICP-OES 38 '
VI
List of Tables
f
Pace
Table 1. 11
Analytical features of INAA & ICP-OES ' ^
i
Table 2.11
Common, scientific names, part used and collection areas of studies medicinal plants
25
j_____
Table 2.2 1
Relevant Nuclear Data for determined radionuclides 27i
Table 3.1 11
Elemental concentration (Mean ± SD mg/kg) of SRM 1547 (peach leaves) using INAA ;
. . . . . . . . . . . . . . . . _______ J _____ ... -
Table 3.2r
j
Elemental concentration (Mean ± SD mg/kg) of reference ERM-CD 281 (rye grass) using ICP-OES
---- . J
30
Table 3.31
1
ICP-OES measurement (Mean ±SD mg/kg) of reference material milk powder (ERM-BB150) 30
Table 3.41
Element concentration (Mean ±SD mg/kg) in Sudanese medicinal j plants obtained by INAA
1|
i11
Table 3.511
Element concentration (Mean ±SD mg/kg) in Sudanese medicinal ! .
plants obtained by ICP-OES !
11. . L
VII
Chapter One
IntroductionLI. Medicinal plantsWorldwide, medicinal plants have been used since time immemorial. They have served as
cheaper alternative to orthodox drugs. A great number of research conducted on these medicinal
plants often focus on the organic action of these medicines with little attention going to the
elemental contents. Due to their potential impact on human health, the pharmacological
properties of these medicines must be studied. The pharmacological properties have been
attributed to active chemical contents (Debrah et al.« 201 1). In recent years, there has been a
gradual revival of interest in the use of medicinal plants in developing countries because herbal
medicines have been reported safe and without any adverse side effect especially when
compared with synthetic drugs. Medicinal plants play significant role in providing primary
health care services to rural people and are used by about 80% of the marginal communities
around the world. Besides that, every human needs a daily supply of different types of food
materials to enable a healthy life. However, the productive value of food depends on the quantity
eaten and the extent to which the food is consumed with the required energy,
and vitamins (Hussain et aL, 2013).
in, minerals
Medicinal plants have evolved over the centuries as essential parts of African civilization and arc
widely recognized today as representing its rich cultural and scientific heritage. The increasing
demand for medicinal plant products has renewed interest in the pharmaceutical industry m the
production of herbal health care formulations, herbal-based cosmetic products, and herbal
nutritional supplements. Thus, in addition to serving medical and cultural functions, medicinal
plants in Africa have economic importance. Global and national markets have been growing for
medicinal herbs, and significant economic gains are being realized through the sale of medicinal
plant products ( Dzoyem et al., 2013).
Medicinal plants have been widely used to treat a variety of infectious and non-infectious
ailments (Mukhtar et al., 2008). They come into preparation of various modern drugs or even
they have been used as the principal source of raw materials for conventional drugs in the
developing countries; these plants are easily found in local market. There is great interest in
tracing the essential elements and the composition in medicinal science; it is believed that the
1
great majority of elements are as key components of an essential enzyme svstem or vital bio
chemical function (Selvaraju et al., 2011).
Sudan has an immense diversity and variation in vegetation and is one ot the richest countries
with regard to phytopharmaca. Although herbal remedies are often perceived as being natural
and, therefore, safe, they are not principally free from adverse effects. While man> investigations
of the quality values of medicinal plants are being reported in the current literature, iess emphasis
has been made on the metal content of herbal products (Ebrahim et al.. 2012).The climate ot
Sudan ranges from completely arid to tropical zones with a wide range of biociimatic regions,
from the almost barren deserts in the North to the tropical rain forests in the extreme South of the
country. The diversity of the climate of Sudan is responsible for its very rich flora. Research on
medicinal and aromatic plants began a long time ago, but this was carried out in a scattered and
unstructured fashion until the establishment of the Medicinal and Aromatic Plants Research
Institute (M A PR I) in 1972 (Eltohami 1997).
1.2. Historical roots of medicine in Sudan
1.2.1. Traditional Sudanese medicine
Sudanese folk medicine represents a unique blend of indigenous cultures of Islamic. Arabic and
African traditions. Consequently, treatments exist for a variety of diseases, both epidemic and
endemic. To face these diseases, people have tapped the environmental resources, e g. plants,
minerals and animal products for the management of their health (Khalid et al.. 2012 > in this
respect, the Sudanese have amassed a large body of curative methods, techniques and recipes.
Readers mav find further recent and detailed information in the descriptive inventorv. whichm/ I r '
appeared in the Atlas of Medicinal Plants series published by Medicinal and Aromatic Plant s
Research (MAPRI). This series includes comprehensive surveys of the medicinal plants Erkavvit.
Nuba Mountains, White Nile, North Kordofan, and Angasana Though not yet investigated
systematically or in depth, there are clues in literature about the bioactivity of medicinal plantv;
and their chemical constituents. Sudanese medicinal plants have been reported to exert
antimicrobial activity against viruses, bacteria, and protozoa (Ahmed et al., 2010). As infection N
with worms or molluscs represent a common affliction in that area, medicinal plants have been
considered for treatment of these infections. Immunomodulatory properties of Sudanese
medicinal plants have also been observed. In this review, we provide an updated overview of the
most important plants used in Sudanese traditional medicines (Khalie et a l . 2012).
2
1.2.2. Overview of medicinal plants in Sudan
The flora of Sudan consists of 3137 documented species of flowering plants belonging to 170
families and 1280 genera. It is estimated that 15% of these plants are endemic to Sudan, The
intersection of cultures and the unique geographical position of Sudan hold great potential for
research in many fields, the most important of which is medicinal and aromatic plants. The
diversity of climates in Sudan results in a rich variety of flora species corresponding to the wide
range of ecological habitats and vegetation zones. In Sudan, it is a common practice to collect
medicinal plants from their natural habitats for home consumption and export. Plants collected
from different localities or geographic regions may have different chemical compositions. This
may be explained by differences in climate, temperature, rainfall, altitude, day length and UV-
radiation, all of which play an important role in plant development and affect the biosynthesis of
secondary metabolites with biological activity. In general, generation of volatile oils appears to
be enhanced at higher temperatures (Khalid et al., 2012). Continuous rainfall can lead to a loss of
water soluble substances from leaves and roots by leaching and also makes collection and drying
more difficult. For example, when peppermint is grown in Sudan under long-day conditions, the
leaves contain high amounts of menthone and menthol with only trace amounts of menthofuran.
whereas peppermint plants grown under short-day conditions contain menthofuran as the major
component. The amount of bitter constituents in Gentiana lutea increases with altitude, whereas
alkaloid contents in Aconitum napellus and Lobelia inflate and essential oils in thymus
peppermint decrease. Pyrethrum delivers the best yield of pyrethrins when cultivated near the
equator and at high altitudes (Khalid et al., 2012).
1.3. Importance of trace elementsTrace element is defined as any element present below -0.1 wt. %. Units such as ppm. ppb. ppt
(parts per million, billion, trillion) are used to describe the concentrations of trace elements in a
system. The human body is composed of elements which can be roughly divided into abundant
elements and trace elements. Abundant elements consist of the major elements that are involved
in the formation of covalent bonds and are important constituents of tissues (oxygen, carbon,
hydrogen, nitrogen, etc.) and of the total body weight, and the semi-major elements account for 3
to 4% of the total body weight. Deficiency of major elements can lead to nutritional disorders,
and their presence in excess can cause obesity (Wada 2004).
3
Essential trace elements of the human body include zinc (Zn), copper (Cu). selenium (Se)
chromium (Cr), cobalt (Co), iodine (1), manganese (Mn), and molybdenum (Mo). Although
these elements account for only 0.02% of the total body weight, they play significant roles, e.g,.
as active centers of enzymes or as trace bioactive substances. A major outcome of trace element
deficiencies is reduced activity of the concerned enzymes (Wada2004). However, since each
trace element is related to so many enzymes, deficiency of a single trace element is often not
associated with any specific clinical manifestations, but rather manifests as a combination of
various symptoms. Because of the presence of trace elements in very small amounts and the
absence of specific clinical features associated with their deficiency, often difficult lor clinicians
to identify deficiencies of some particular trace elements ( Wada 2004).
1.3.1. ChromiumCr plays an important role in diabetes treatment. It is an important element required for the
maintenance of normal glucose metabolism. The function of Cr is directly related to the
function of insulin, which plays a very important role in diabetes. Cr deficiencies in diet
produce elevated circulating insulin concentrations, hyperglycemia, hypercholesterolemia,
elevated body fat, decrease sperm counts, reduce fertility, and shorten life span. Cr is found in
the pancreas, which produces insulin. One usable form of Cr is the Glucose Tolerance Factor
(GTF). The important constituent of GTF is Cr which helps in potentiating of insulin. Chronic
exposure to Cr may result in the liver, kidney and lung damage (Zetic et ai, 2001)
1.3.2. Copper
C'u In humans is necessary for the development of connective tissue, nerve coverings, and bone.
It is also participates in both Fe and energy metabolism .Cu acts as a reluctant in the enzymes
superoxide dismutase and several others oxidizes that reduce molecular oxygen. There is about
80 mg of Cu in the adult body and median intake of Cu ranges between 1.0 and 1.6 mg/day in
adults. Good sources of dietary Cu are liver and other organ meats, oysters, and nuts, seeds dark
chocolate and whole grains. Cu deficiency in humans is rare, but when it occur leads to anemia,
leucopenia and inclusive osteoporosis in children. Excessive dietary Zn can cause Cu deficiency.
Chronic Cu toxicity is rare in humans, and mostly associated with liver damage. Acute Cu
intoxication leads to gastrointestinal effects characterized by abdominal pain, cramps, nausea,
diarrhea, and vomiting (Fraga 2005)
4
1.3.3. IronIron is the most abundant trace element in human bodv, a structural component in heme protein s
hemoglobin, myoglobin, and cytochrome-dependent proteins (Griffiths 2007).A large quantity is
also stored in proteins like ferritin and hemosiderin. Its role is in oxido-reduction. by conversion
of the Fe (II) and Fe (III) forms. The free ion would cause oxidative stress. Iron deficiency leads
to severe anemia. Excess iron can give gastrointestinal problems, vomiting, and diarrhea, ending
with cirrhosis for chronic exposure. It may also be carcinogenic. Hemochromatosis is a genetic
disease in which iron is absorbed in excess from the diet and accumulates in different tissues
with altered distribution (Griffiths 2007).
Iron interacts with other metals: copper, manganese, zinc, and chromium. Iron-binding proteins
can bind other cations, such as manganese, zinc, and vanadium, thereby contributing to their
transport (Ballatori 2002).
1.3.4. MagnesiumMagnesium is an intracellular ion which acts as a cofactor in oxidative phosphorylation in the
synthesis or utilization of ATP (e.g. in muscle contraction). Many of the adhesion molecule
I.e. proteins involved in direct cell-cell contact have magnesium located at the binding site of
the molecule. Its plasma concentration relative to calcium affects nerve transmission and
muscular contraction. The concentration of substances likes fattv acids, phvtate. and
phosphorous in the gut contents affects magnesium absorption. Its absorptive pathway is
common with calcium (Makrides and Adelaide 2010).
Mg deficiencies encourage deposits of unabsorbed minerals upon heart muscles., kidneys and
arteries. The kidneys are very efficient at maintaining body levels, but not in cases where the diet
is deficient. Mg acts in the cells of all the soft tissues, where it is part of the protein-making
machinery and is necessary for the release of energy. A fair amount of information on these
elements and their roles in various physiological processes, their ways of functioning and
necessity would be of paramount importance to understand the progression of various diseases
and their remedies (Selvaraju et al., 2011).
1.3.5. Zinc
Zn is another essential, relatively non toxic and enzymatic metal for both plant and animal. Zn is
necessary for the growth and multiplication of cells (enzymes responsible for DNA and RNA
synthesis), for skin integrity, bone metabolism and functioning of taste and eyesight. Zn plays an
5
important role in production, storage, and regulation of insulin, Zn deficiency is characterized b>
recurrent infections, lack of immunity and poor growth. Growth retardation, skin changes, poor
appetite and mental lethargy are some of the manifestations of chronicallv Zn-deficient. human
subjects. The high concentration of Zn in flowers suggests its possible use m sex tome, treatment
of worms, eve trouble and skin disease. Zn is essential for the function of the immune svstem
cells and Zn has been shown to be effective in the treatment of common cold (Mossad a a/..
1996). Zn is also required for the activity of more than 100 enzymes associated with
carbohydrate and energy metabolism, protein degradation and synthesis (Selvaraju ei ui., 201 1).
1.3.6. CalciumCalcium is an important trace element because of its role in bones, teeth, muscular system and
heart functions. It is required for the absorption of dietary vitamin B. for the synthesis of the
neurotransmitter acetylcholine, for the activation of enzymes such as the pancreatic lipase
(Lokhande et al., 2010). Calcium is necessary for the coagulation of blood, the proper
functioning of the heart and nervous system and the normal contraction of muscles. Its most
important function is to aid in the formation of bones and teeth (Saraf and Samant 2013 ).
1.3.7. PotassiumPotassium ions are the most abundant cations in the human body. It is extremely important for
the cells in the body. It is essential for smooth flow' of communication signals from cell to cell
and its deficiency can contribute to diseases like stroke, heart problem, diabetes and
hypertension. It acts in the intercellular fluid as the primary ion. Potassium together with sodium
helps to regulate the water balance within the body. It regulates the transfer of nutrients to th v
cell, transmits electrochemical impulses and is necessarv for normal growth and enzvmaticA w w
reactions. The average human consumes potassium up to 7 gm a day and has a store of
some 140 gm in the human body, mainly in the muscles. K is of importance as a diuretic
(Raman et al., 2013).
1.3.8. Manganese
The kidney and liver are the main storage places for the manganese in the body. Mn is essential
for normal bone structure, reproduction and the normal functioning of the centra! nervous
system. Its deficiency causes reproductive failure in both male and female. Mn is also important
for several enzymatic processes. It helps in eliminating fatigue and reduces nervous irritability
(Lokhande et al., 2010).There are two enzymes known to contain Mn; pyruvate carboxylase and
6
superoxide dismutase (Niamat et al., 2012). Apart from physiological importance experimenta
data have pointed out the pharmacological implication ot this element especial 1\ m
prevention and treatment of diabetes mellitus (Debrah et a/.,(2011).
1.3.9. CobaltCobalt is an essential trace element and forms part of the active site of V itamin B:: . The amount
of cobalt required in the human body is very small and it contains only about 1 mg, Cobalt salts
in small doses have been found to be effective in correcting mineral deficiencies m certain
animals. But in large doses it is carcinogenic. There are no established criteria limits for cobalt m
medicinal plants (Raman et al., 2013),
1.3.10. StrontiumStrontium (Sr) is a mineral with a reported effect on the reduction of bone fracture risk.
Strontium is able to substitute for calcium in hydroxyapatite (bone crystal}. The uptake of high
strontium concentrations is generally not known to be a great danger to human health In one
case someone experienced an allergic reaction to strontium, but there have been no similar cases
since. For children exceeded strontium uptake may be a health risk, because it can cause
problems with bone growth. When strontium uptake is extremely high, it can cause disruption of
bone development. But this effect can only occur when strontium uptake is in the thousands ot
ppm range. Strontium levels in food and drinking water are not high enough to be able to cause
these effects (http://www.lenntech.com/periodic/elements/sr.htm).
1.4. Role of trace elements in medicinal plantsTrace elements play a very important role in the formation of the active chemical
constituents present in medicinal plants. However, a direct correlation between elemental
composition of the medicinal plants and their curative properties has not been established yet.
The quantitative estimation of various trace element concentrations is important for
determining the effectiveness of the medicinal plants in treating various diseases and also
to understand their pharmacological action. The elemental status of plant is necessary for new
drug development research in raw herb. Therefore, proper scientific investigations are required
to explore the exact medicinal potential of plants. This is very important not only for the
safety of consumers, but also for medical advisors (Selvaraju et aL, 201 1).
Most of the trace elements are essential to life, but thev can have deleterious effects when' r'
present in excess. Death and disease related to acute or chronic exposure have been
7
documented for some of the essential trace elements. It is essential to know the trace elemental
concentration in medicinal plants from the point of view of’ nutritional requirement and
intoxication risk associated with their consumption. The effects and influence of trace elements
on administration of medicinal plants is also essential to understand the pharmacological
action of herbs and to decide the dosage of the herbal drugs prepared from these plant
materials (Raju et al., 2013).
The elemental composition of many plants is known. It will be very interesting to determine their
trace elements’ status. It is surprising to note that many curative effects of medicinal plants used
in the traditional system of medicines are due to the presence of very minute quantities of trace
elements. Important constituents of the body such as enzymes are intimately associated with the
chemical elements. Elements, particularly essential trace elements play both curative and
preventive roles in fighting diseases such as Fe in anemia and iodine in goiter. The deficiency of
trace elements in human subjects can occur under most practical dietary conditions. Many
diseases which have been considered incurable may now possibly be treated by balancing the
disequilibrium of these elements in the human body (Shirin et al., 2009).
1.5. Instrumentation
1.5.1. Instrumental Neutron Activation Analysis (INAA)The accurate determination of trace concentrations of elements in complex matrices such as
rocks, soils, plants and sediments are very important in both mineral exploitations and soil
fertility mapping. Methods that can be used for the analysis materials such as atomic absorption
spectrometry (AAS), inductively coupled plasma-atomic emission spectrometry (ICP-AES) or
mass spectrometry (ICP-MS), all of which require dissolution and sometimes subsequent
chemical treatment of the sample to ensure full dissolution with the inherent risk of
contamination .However, a method with widest acceptance and unique advantages in areas such
as sensitivity, speed, precision, cost, low matrix effects, and preservation of sample known as
Instrumental Neutron Activation (1NNAA) (Funtua et al., 2012).
INAA is one of the most reliable methods for measuring the elements, regardless of
chemical form. It does not require complicated sample digestion steps, which minimizes
the possibility of analyte loss and contamination. It is less strongly affected by the matrix
of the sample because of the high penetration power of neutrons and gamma rays and is
not affected by the chemical and physical states of the analyte elements (Kim e/a/.. 2013).
8
INAA has been commonly used to perform multi elemental analysis in a variety of
environmental studies due to its sensitivity and accuracy (IAEA-1215. 2001). Furthermore.
INAA based on the relative method is used to maintain the high level of accuracy required.
However, it is important to adjust experimental parameters for an optimization and to give
results within statistical control. Manv elements can be determined with higher sensitivity b\
optimizing the irradiation, decay and counting times (El-Taher and Alharbi 2013). Also i\A A
has been used for the assessment of elemental composition in soils successfully (Haciyakupogiu
et al., 2014). NAA is considered as the referee method of choice when new procedures are being
developed or when other methods yield inconsistent results do not agree. Nevertheless, until
recently, its applicability was not possible in many cases and in many matrices where final
sensitivity was affected and reduced by the limited performance of detectors and electronics.
Very recently, a new generation of digital signal processing-based germanium y-ray
spectrometers has provided unprecedented superior performance (Hamidatou et al.. 2013). This
new technology allows dramatic improvements on the previous analogic electronic chains,
giving a combination of high resolution, throughput, count rate stability and long-term stability
of both resolution and peak shape. In applications involving high or widely varying count rates,
the new systems allow the best resolution and peak stability, providing excellent y spectra for an
accurate analysis of samples of different origin and composition (Kharfi 2013 ).
Neutron activation analysis (NAA) is a nuclear process used for determining the concentrations
of elements in a vast amount of materials. NAA relies on excitation by neutrons so that the
treated sample emits gamma-rays. It allows the precise identification and quantification of the
elements, above all of the trace elements in the sample. NAA has applications m chemistry
but also in other research fields, such as geology, archaeology, medicine, environmental
monitoring and even in the forensic science (Hamidatou et al., 2013).
1.5.1.1. Basis principlesThe sequence of events occurring during the most common type of nuclear reaction used for
NAA, namely the neutron capture or (n, y) reaction, is illustrated in Figure 2.1. Creation of a
compound nucleus forms in an excited state when a neutron interacts with the target nucleus via
a non-elastic collision. The excitation energy of the compound nucleus is due to the binding
energy of the neutron with the nucleus. The compound nucleus will almost instantaneously de-
excite into a more stable configuration through emission of one o> more characteristic prompt
9
gamma rays. In many cases, this new configuration yields a radioactive nucleus which also dc-
excites (or decays) by emission of one or more characteristic delayed gamma rays, but at a
much lower rate according to the unique half-life of the radioactive nucleus Depending
upon the particular radioactive species, half-lives can range from fractions of a second to several
years (Kharfi 2013),
In principle, therefore, with respect to the time of measurement, NAA falls into two categories:
prompt gamma-ray neutron activation analysis (PGNAA). where measurements take
place during irradiation. The PGAA technique is generally performed by using a beam
of neutrons extracted through a reactor beam port. Fluxes on samples irradiated in beams
are in the order of one million times lower than on samples inside a reactor but detectors
can be placed very close to the sample compensating for much of the loss in sensitivity
due to flux. The PGAA technique is most applicable to elements with extremely high
neutron capture cross-sections (B, Cd, Sm, and Gd); elements which decay too rapidly to
be measured by DGAA; elements that produce only stable isotopes (e.g. light elements):
or elements with weak decay gamma-ray intensities. 2D, 3D analysis of (main ) elements
distribution in the samples can be performed by PGAA (Kharfi 2013),
Delayed gamma-ray neutron activation analysis (DGNAA), where the measurements
follow radioactive decay. DGNAA (sometimes called conventional NAA) is useful for
the vast majority of elements that produce radioactive nuclides. The technique is flexible
with respect to time such that the sensitivity for a long-lived radionuclide that suffers
from interference by a shorter-lived radionuclide can be improved by waiting for the
short-lived radionuclide to decay or quite the contrary, the sensitivity for short-lived
isotopes can be improved by reducing the time irradiation to minimize the interference of
long-lived isotopes (Hamidatou et ah, 2013),
1 0
neutron b -pkirtjc If
* * m •* * *ca pfu re
# *
#■ * * * ♦ ' ■ # *
&
A yZ *
** ** •*/ - VI* * * 4 *• * # * •"
• # <
UJor npo uncinucleus
A+12 X’
iv e
A*121X
rofri|;»f ciarnfriai actatiori POAA
\decay
\
A* 1Zi1 X A-1
7 - 1k t o 11 ijM-h
X* \ .jtjcay lyamriv radiation
NAA
Figure 1.1: Diagram illustrating the process of neutron capture by a target nucleus followed by
the emission of gamma rays
This selectivity is a key advantage of DGNAA over other analytical methods. In most cases, the
radioactive isotopes decay and emit beta particles accompanied by gamma quanta of
characteristic energies, and the radiation can be used both to identify and accurately quantify the
elements of the sample. Subsequent to irradiation, the samples can be measured instrumentally
by a high resolution semiconductor detector, or for better sensitivity, chemical separations can
also be applied to reduce interferences. The qualitative characteristics are: the energy of the
emitted gamma quanta (Ey) and the half life of the nuclide (Tv,). The quantitative characteristic
is: the 1 intensity, which is the number of gamma quanta of energy Ey measured per unit time
(Hamidatou et al., 2013). For example, consider the following reaction:58Fe + n 59 Fe + Beta’ + gamma rays58 59Fe is a stable isotope of iron while Fe is a radioactive isotope. The gamma rays emitted
during the decay of the 39Fe nucleus have energies of 142.4, 1099.2. and 1291.6 KeV.
and these gamma ray energies are characteristic for this nuclide (Be et al.. 2004). The (n. y)
reaction is the fundamental reaction for neutron activation analysis
11
The probability of a neutron interacting with a nucleus is a function of the neutron energy Thi s
probability is referred to as the capture cross-section, and each nuclide has its own neutron
energy-capture cross-section relationship. For many nuclides, the capture cross-section is
greatest for low energy neutrons (referred to as thermal neutrons). Some nuclides have greater
capture cross-sections for higher energy neutrons (epithermal neutrons). For routine neutron
activation analysis we are generally looking at nuclides that are activated by thermal neutrons.
The most common reaction occurring in NAA is the (n. y) reaction, but also reactions such as (n.
p). (n, a), (n, n') and (n, 2n) are important. The neutron cross section, a. is a measure for the
probability that a reaction will take place, and can be strongly different for different reaction
types, elements and energy distributions of the bombarding neutrons. Some nuclei, like
‘ "U are fissionable by neutron capture and the reaction is denoted as (n, 0- yielding fission
products and fast (highly energetic) neutrons (Hamidatou et a l , 2013).
I.5.I.2. INAA how does it work?
A gamma-ray spectroscopy system consists of a detector (and high voltage pow er supply for the
detector), pre amplifier, spectroscopy amplifier, analog-to-digital converter, multi-channel
analyzer, and an output device. A sample is presented to the detector (Ge in the case of gamma-
ray analysis). In order to minimize thermal noise the detector is kept at cryogenic temperatures
(liquid nitrogen, temperature = 77K). The initial signal is very small and the pre-amplifier,
attached directly to the detector, amplifies this signal. The signal is shaped by the spectroscopy
amplifier and then converted from an analog to a digital signal by the analog-to-digital converter
The results are stored in digital form (multi-channel analyzer). In modern gamma-ray
spectroscopy systems the high-voltage power supply, spectroscopy amplifier, analog-to-digital
converter, and multi-channel analyzer are combined into a single module. A computer is used to
visually show' the resulting spectrum and to do calculations on the spectrum. Various algorithms
are used to determine the shape and energy of each gamma-ray peak present in a spectrum and to
determine the area encompassed by the peak (i.e., the gamma-ray intensity). Subsequent decay,
interference (if required), fluence, fission product corrections, and comparison with a standard
lead to a quantitative analysis figure 1.2.
12
Figure 1.2: Flow chart for a gamma-ray spectroscopy system
1.5.1.3. Neutrons sources26 ^ c ^( j ^ a ,J) f ■; ^
• Isotopic neutron sources'. like Ra (Be). ' Sb (Be), “ ‘Am (Be). J Cf. The neutrons have
different energy distributions with a maximum in the order of 3--4 MeV; the total output iS
typically KT-lO's GBq'or, for 252Cf, 2.2* 10
• Particle accelerators or neutron generators: The most common types are based on the
acceleration of deuterium ions towards a target containing either deuterium or tritium, resulting^ ^ 'i
in the reactions _H(2H,n) He and H(2H,n) He. respectively. The first reaction, often
denoted as (D.D). yields mono-energetic neutrons of 2.5 MeV and typical outputs m the order
p j I
“s' g' (Hamidatou ei ai. 013).
of 108-1010 -s ; the second reaction (D,T) results in monoenergetic neutrons of 14.7 MeV
and outputs of 109— 1011 s 1 (Kharfi 2013),
'Nuclear research reactors: The neutron energy distribution depends on design of the reactor
and its irradiation facilities. An example of an energy distribution in a light water moderated
reactor the major part of the neutrons has a much lower energy distribution that in isotopic
sources and neutron generators. The neutron output of research reactors is often quoted as
neutron fluence rate in an irradiation facility and varies, depending on reactor design and15 1 1 > • ^
reactor power, between 10 and 10 m'V . Owing to the high neutron flux, experimental
nuclear reactors operating in the maximum thermal power region of 100 kW -10 MW with a
-i
j ^ J J • «J
maximum thermal neutron flux of 10-10 neutrons cm “s are the most efficient neutron
sources for high sensitivity activation analysis induced by eoitherrna! and thermal neutrons. The
reason for the high sensitivity is that the cross section of neutron activation is high in the thermal
13
region for the majority of the elements (Hamidatou et ai. 2013). There is a wide distribution ot
neutron energy in a reactor and, therefore, interfering reactions must be considered, in order to
take these reactions into account, the neutron spectrum in the channels of irradiation should be
known exactly. E.g. if thermal neutron irradiations are required, the most thermalized channels
should be chosen. Although there are several types of neutron sources (reactors, accelerators, and
radioisotope neutron emitters) one can use for NAA. nuclear reactors with their high fluxes of
neutrons from uranium fission offer the highest available sensitivities for most elements.
Different types of reactors and different positions within a reactor can vary considerably with
regard to their neutron energy distributions and fluxes due to the materials used to moderate (or
reduce the energies of) the primary fission neutrons. This is further elaborated in the title
"Derivation of the measurement equation". In our case, the NAA method is based on the use of
neutron flux in several irradiation channels of the research reactor (Hamidatou et ai. 2013).
In many cases NAA can be performed nondestructive!}', this analysis mode being termed
instrumental NAA (INAA). In the cases where the induced radionuclides of trace
elements are masked by matrix activity, a radiochemical separation (i.e. a post-irradiation
procedure) is mostly used to eliminate matrix activity or to separate the radionuclides of interest
in the so called radiochemical NAA (RNAA) (IAEA-TECDOC-1121-1999).
1.5.2. The General Equation of Neutron Activation Technique
LetN be the number of radioactive nuclei produced during irradiation t. a be the cross-section of
the reaction, O the neutron flux, n number of target nuclei and A the decay constant of the
radionuclide formed (Shaddad 1995).Then we have the following differential equation
dN_~dt
— <£>cr n - AN
Where the first term on the R.H.S describes the increase of N because of the activation process,
while the second term given the decrease of N due to decay
The general solution of such differential equation is:
N = e{- A,)[c + <7 n J<D(f) e(k,)dt
Where the flux <t> is assumed to be time dependant and C is a constant of integration. However
if the flux is constant, i.e. 0= O0 and assuming the initial condition N=0 at t =0. then we have
N(t) = Oocr /7(1 - eA
(-;.o(3)
14
(4)
The activity at time t will be
A{t) = XN{t) = <£>ocr n - e {-At )
After the end of irradiation, A decrease exponentially and after a time ti following end of
irradiation we have
Alt1 Alt) e -A lt=t(5)
If the activity measurement is preformed during the time interval between tj and t;. then the
expected number of decay events Ac will be given by:
A<3> o cr n e (- A e (-*(/ - t ,)) 1 (- / _ ))
c A(6)
Where, t=t, is the irradiation time, ti-t=tw is waiting time and t;-ti is the counting time
Accordingly equation (6) can be written as
AO oct n l (- >. *, ) 1 e I-'Ak ))
c x (7)
Clearly, the average number of counting decay events Nc will be less than A, due different
effects such as the efficiency of the detector£ for the particular energy and for the particular
counting geometry, and the intensity of the measured gamma line 1 so :
K = eIAc
Also the number of target nuclei is given by
( 8 )
n =N
a
Wmf(9)
Where m = the mass of the element in the sample. W = the atomic weight. Na =Avoaadro’s
number=6,02.10“ mole"1, f = the relative isotopic abundance ofthe target isotope.
From the equations (7), (8) and (9) we have for the basic equation of neutron activation analysis:
-i
Ac =N am f Q o a e I (l e (- / u ) 1 e
W X ( 10)
15
1.5.3. Types of standardizationFor the determination of element concentrations in NAA three types ot standardization
(calibration) can be used:
• relative (using synthetic, mostly multi-element standards)
• single-comparator, most frequently employing the so called kf,-standardization
• Absolute (parametric).
Since unacceptable uncertainties are still associated with the values ot nuclear
parameters, namely activation cross sections o0, resonance integrals 10. gamma ray emission
probabilities y. and isotope abundances 0 (in order of decreasing importance), the absolute
standardization is used only rarely and will not be dealt with in the present report (IAEA-
TECDOC-1121-1999).
In the relative standardization method, a chemical standard with a known mass of the
element is co-irradiated with the sample of a known mass and both are counted, usually in the
same11 “
eometrical arrangements with respect to the HPGe detector, so that the absolute
efficiency of the detector need not be determined. When short-lived radionuclides are to be
measured both the standard and sample may be irradiated separately using the same reactor
conditions, usually with a monitor of the neutron fluence rate.
In the case of relative standardization, the analysis results are traceable to the materials used in
the preparation of standards. Depending on the purity and stoichiometry of the compounds used,
traceability to the mole can be established (IAEA-TECDOC-1 121-1999 ).
The concept of the k0-standardization in NAA. one of the most frequently used single-
comparator (mono-standard) methods, is based on co-irradiation of the sample and a neutron
fluence rate monitor and the use of an experimentally determined composite nuclear constant kft
Details of the ^.-standardization have extensively been described in the literature (De Cone
1987), In the case of ^-standardization; the analytical results are linked to the k«-factors.
absolute detector efficiency and neutron spectrum characteristics. The k0-factors have been
reliably determined in two independent measurements which were related to purity and
stoichiometry of various materials (IAEA-TECDOC-1 121-1999). The absolute detector
efficiency calibration is routinely performed using internationally recognized radioisotope
standards. For determining the neutron spectrum characteristics, internationally recognized
16
certified reference materials for neutron dosimetry are available, (high purity metals or Ai
alloys containing certified amounts of Au. Co. In and U) (IAEA-TECDOC-1121-1999),
1.5.3.1. The ko-comparator methodThe ko-based neutron activation analysis (ko-NAA) technique, developed in 1970s. is being
increasingly used for multi-element analysis in a variety of matrices using reactor
neutrons (De Corte et at., 1987). In our research reactor, the ko-method was successfully
developed using the Hogdahl formalism. In the ko-based neutron activation analysis the
evaluation of the analytical result is based on the so-called k0- factors that are associated with
each gamma line in the gamma-spectrum of the activated sample (Hamidatou et at., 2013 ). These
factors replace nuclear constants, such as cross sections and gamma-emission probabilities, and
are determined in specialized NAA laboratories. This technique has been reported to be
flexible with respect to changes in irradiation and measuring conditions, to be simpler than the
relative comparator technique in terms of experiments but involves more complex formulae and
calculations, and to eliminate the need for using multi-element standards. The ko-NAA
technique, in general, uses input parameters such as ( 1) the epithermal neutron flux shape factor
(a), (2) subcadmium-to-epithermal neutron flux ratio (/), (3) modified spectral index r (a) vT„
To, (4) Westcotf s g(Tn)-factor, (5) the full energy peak detection efficiency (£p),and (6) nuclear
data on Qofratio of resonance integral (Io) to thermal neutron cross section (Go) and k,,. The
parameters from (1) to (4) are dependent on each irradiation facility and the parameter (5) is
dependent on each counting facility. The neutron field in a nuclear reactor contains an epithermal
component that contributes to the sample neutron activation (Mustra et at., 2003) Furthermore,
for nuclides with the Westcotf s g (Tn) factor different from unity, the Hogdahi convention
should not be applied and the neutron temperature should be introduced for application of a more
sophisticated formalism (De Corte et at., 1987) the Westcott formalism. These two formalisms
should be taken into account in order to preserve the accuracy of ko-method. The ko-NAA
method is at present capable of tackling a large variety of analytical problems when it comes to
the multi-element determination in many practical samples.
I.5.4.2. Applications, advantages and limitations of NAAWhile liquid samples (if certain precautions are taken) can be analyzed by INAA, solids are
the matrix of choice for this technique. Virtually any material can be analyzed and limitations
are largely due to the chemistry of the matrix. For example, it would be difficult to obtain low
17
detection limits for a sample of pure iron because given the half-life (44.6 days) of Te„ the
sample will have a high background for an extended period of time and shorter half-life
isotopes will be gone from the sample before this background is reduced. Examples of the ty pe
of materials that can be analyzed by 1NAA are:
• Rocks, minerals, and soils
• Atmospheric aerosols
• Archaeological artifacts
• Tree rings
• Dust in ice cores
• Hair, nails, skin, etc.
• Plant and animal matter
• Coal
Advantages of NAA:
Activation analysis measures the total amount of an element in a material without regard to
chemical or physical form and has the following advantages:
(1) Samples for NAA can be liquids, solids, suspensions, slurries, or gases. Samples do not have
to be put into solution or vaporized.
(2) One of the most important a advantage of NAA is that it is nearly free of any matrix
interference effects because the atoms of matrix are composed of H. C, O, N, P. and Si that do
not form any radioactive isotopes. This makes the method highly sensitive for measuring trace
elements, thus the vast majority of samples are completely transparent to both the probe (the
neutron) and the analytical signal (the y-ray) (Verma 2007).
(3) NAA is nondestructive in that the integrity of the sample is not changed in any manner by
pre-chemistry or the addition of any foreign materials before irradiation - thus the problem of
reagent-introduced contaminants is completely avoided (Verma 2007).
(4) NAA requires only small amounts (100-200 mg) of sample material.
(5) The analytical approach for NAA for most elements of interest is primarily an instrumental
technique and does not require any post irradiation chemistry (Verma 2007).
(6) NAA is a multi-element analytical technique in that many elements can be analyzed
simultaneously in a given sample y-spectrum without changing or altering the apparatus as is
necessary in atomic absorption.
18
(7) NAA is fast in that many samples can be irradiated at a given time for main elements and
counted later on a given decay schedule.
(8) Sensitivitv to trace elements: The sensitivity obtained by activation analysis is a lunctior v > i
the neutron cross-section of the element in question, available neutron flux, length of irradiation,
resolution of the detector, matrix composition, and the “total’" sample size. Hence, increasing
neutron fluxes, increased irradiation times, and the major advances in nuclear detector
technology in the areas of increased efficiency and resolution have pushed the detection limits ot
most elements of interest to the very low levels.
Limitations of"NAA are:
V1) Interferences can occur when different elements in the sample produce y-ray s ot nearly the
same energy. Usually this problem can be circumvented by choosing alternate v-rays for these
elements or by waiting for the shorter-lived nuclide to decay prior to counting. The limit of
detection for a particular element will depend upon the measured count rate of the y-ray being
monitored and the background upon which that y-ray peak sits. The measured count rate for a
given isotope can be increased by (a) increasing the detector efficiency (moving the sample
closer to the detector) (b) increasing the irradiation time and (c) decreasing the decay time. The
sensitivity of the measurement can in many cases be improved by increasing the overall signal or
total number of counts. This is accomplished by simply increasing the measurement time.
2) The limit of detection for an element can be lowered if we increase the ratio of the activity of** ++
the y-ray of interest to the background through any combination of steps (a), (b ) or (c) mentioned
in (1). Conversely, changing the detector efficiency, irradiation time, or decay time to cause a
lower peak-to-background ratio will worsen the detection limit. The change in -to-
background ratio is primarily a function of the activity of other isotopes produced in the neutron
irradiation of the sample.
3) The most important limitation is that it takes a lot of time to complete a full analysis Because
all radioactive isotopes have different half-life times, they can be divided into three categoric s:
short-lived nuclides (half-life time from less than Is up to a few hours), middle-living nuclides
(half-life time of a few hours up to several days), and long-living nuclides (half-life time of
several days up to weeks, months or even years). When one wants to measure the elements
which form long half life radionuclides, one has to war for a fewr weeks m order that the
19
nuclides with short- and middle half-life times can decay and should not cause any interference,
and make the detection limits better.
A few elements like Pb, Cu, Al, P, S, etc. have small capture cross-sections and short radioactive
half-lives and are thus difficult to detect. The XRF technique has an advantage over NAA
technique due to these reasons (Verma 2007).
1.5.4. Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES):
Inductively coupled plasma-optical emission spectroscopy (ICP-OES) is a powerful tool
for the determination of metals in a variety of different sample matrices. With this technique,
liquid samples are injected into a radiofrequency (RF)-induced argon plasma using one of a
variety of nebulizers or sample introduction techniques (Boss and Fredeen 1997). The sample
mist reaching the plasma is quickly dried, vaporized, and energized through collisional excitation
at high temperature. The atomic emission emanating from the plasma is viewed, collected with a
lens or mirror, and imaged onto the entrance slit of a wavelength selection device. Single
element measurements can be performed cost effectively with a simple monochromator-
photomultiplier tube (PMT) combination, and simultaneous multi-element determinations are
performed for up to 70 elements with the combination of a polychromators and an array
detector. The analytical performance of such systems is competitive with most other inorganic
analysis techniques, especially with regards to sample throughput and sensitivity (Ghosh et
al.. 2013).
The fundamental operating principle governing the ability of an inductively coupled plasma
optical emission spectrometer to analyze a sample is the ability of the atoms constituting a
sample to emit light at certain wavelength (Fig 1.3).
20
Digital Da
OpticalPath
ji_i i - •
b , rv
\
\Detector
Torctv
Nebulizer &Spray Chamber
.a Captureand Instrument
ControlI jJ! !r — vIb
HCP
Plasma Gas Auxiliary Gas
NebulizerGas
■Sample
Figure 1.3 Schematic representation of a radial ICP-OES
m
Exoit i o n«Ato nria i mission
Fig 1.4 The excitation, relaxation and subsequent emission of light from electrons, at
wavelengths of 330nm and 590nm, in the sodium atom
The ability of atoms, or ions, to emit light is derived from the ability of the plasma to
excite atoms, or ions. Excitement of an atom or ion occurs in the case of the SC P. by absorption
of thermal energy by atoms, or ions, causing electrons to undergo transitions to higher
21
[ w v V * Ienergy orbitals (Fig 1.4). As the excited electrons return to the ground-state energ}
energy is emitted in the form of photons of defined energv
Each element has a unique emission spectrum derived from ns unique electronic
configuration. The emission wavelengths associated with each element are derived from ihe
difference between the energy levels involved in each of the orbitals that partake in the energ}
transitions of the electron. The number of emission wavelengths, associated with a particular
atom or ion, will increase with an increase in the number of electrons associated with the
nucleus Once emission spectra have been generated, these spectra have to be detected and
recorded (Downer 2008). This is accomplished writh the use of a spectrometer, which splits
the composite radiation emitted by the sample into separate wavelengths and measures the
intensity of the desired wavelength.
ICP-OES is a fast, accurate, precise and relatively easy to use multi-element analytical technique.
The calibration curves generated are linear over approximately five orders of magnitude. T he
practical limits of quantification can be as low as lOOng.mL^.This technique is most suitable for
analyzing elements in the concentration range of O.lto I0,G00|ig.g~'( which translates to 0.01%
to 100% (by weight) in an actual solid sample (Downer 2008).
The following is a list of some beneficial characteristics of the ICP source (Ghosh et al. 2013)
High temperature (7000-8000 K)
High electron density (1014-1016cm3)
Appreciable degree of ionization for many elements simultaneous multi v lement
capability (over 70 elements including P and S)
• Low background emission and relatively low chemical interferences
• High stability leading to excellent accuracy and precision
• Excellent detection limits for most elements (0.1 -100 ng mL)
• Wide linear dynamic range (LDR) (four to six orders of magnitude)
• Cost-effective analvsis
22
Table 1.1 Analytical features of INAA & ICP-OES
Analytical features11
il
INAA j ICP-OES|
l---------------------------------------------
Accuracy11
Excellent j Excellent!i
LOD1
Excellent Goodiii
ii
Sample Typej
solid & liquid : Liquid, i I !
j... ............... i .
Multi-elemental1
i
i
Yes | Yes1 1
1
i
Matrix Effects Low | Mediumi]i
Spectral Interference Low I High1
i1i
Detection LimitsL
0.001-1 ug/g i-30ng/mi1
i4
1i
________ {
Instrument Priceili
i
More than $250.0000 j $100,000 to $250,00011111
23
Chapter Two
Material and Methods2.1. Sample collectionFourteen popular Sudanese medicinal plants were collected from a local market in
Sudan. Botanical identification and authentication of the collected species with
deposition of herbarium specimens have been done by the Medicinal and Aromatic
Plants Research Institute (MAPRI) - National Center for Research-Sudan. Common,
scientific names and collection areas of studies medicinal plants are given in Table2.l.
2.2. Sample drying and homogenizing
Samples were dried at room temperature before transportation to the laboratory. There,
freeze drying was applied at 101 °C sample temperature (Christ-Heraeus Beta freeze
dryer, Osterode, Germany) for four days until weight constancy was reached. Aliquots
of the plant material were cut into small pieces using a ceramic knife and subsequently
ground and homogenized using an agate ball mill. The resulting fine powder was used
for analysis (Ebrahim et al., 2012).
2.3. ICP-OES measurement
2.3.1. Sample preparation
The dried and homogenized samples were properly weighed into quartz vessels (around
100 mg). Subsequently, 1 mL HNO3, suprapure, sub-boiling distilled (Merck.
Darmstadt) was added. The vessels were closed and introduced into a pressure digestion
system (Seif, Unterschleissheim) for 10 h at 1701C. The resulting clear solutions were
diluted to 10.00 mL with Milli-Q H20 (Ebrahim et al., 2012).
24
Table 2.1: Common, scientific names, part used and collection areas of studies medicinal plants
Botanical namei
Local namei■ FamilyiPart used Collection area
Acacia nilotica (L.) Willd. Ex Del.
El-Garad. . . . . . . . ------------- r
Mimosaceae ' Fruits Khartoum Nilei
! Bank1
Acacia Senegal (L.) Willd.
-------------- 1--- --- rAl-hashab Fabaceae- ! Lxudates and , Al Obeid
!! Mimosoidae Woods
Balanites aegyptiaca (L.)Del
Laloub1
1
Balanitaceaciiij
Fruits and Gedarili; Seeds! Seeds Ai l awCajanus cajan (L.)Millsp. Aladsia ' Fabaceae-
PapilionoidaeCapsicum frutescens L.
tShatta Solanaceae
!fruits Khartoum Nile
bankCitrullus colocynthis (L.)Schrad,
Al-handal1------------
Cucurbitaceae Fruits and West Omdurman Seeds
Cucurbita maxima L. Al Garah Aseli I Cucurbitaceae j Seeds Sinnar:
!
CymbopogonproximusSt—
Maharaib Poaceae i Leaves Butanai_____________________________________________________________________________________________________
Foeniculum vulgare P .
M ill.Alshamar Apiaceae \ Whole plants i Dongola
11L
Guiera senegalensis J.F.Gmel.
Gubeish Combretaceae"
Leaves Tandalti
Stems Abu FlamedHaplophylumtuberculata Flazai
Rutaceae
Lawsonia inermis L.- --- |
HennaJ
iLvthraceae 1 Leaves Khartoum localw’ 1i
marketNieella sativa L.
11______________________ 1
" ” 1 AlkamoonAlasod 1
--------------------------------------- T
Ranunculaceaei... . i
Seeds Khartoum local, marketI?
Salvadora persica L. Arakii Salvadoraceae i Leaves Kassala
11l
25
2.3.2. Sample analysisAn ICP-OES “Spectro Ciros Vision” system (SPECTRO Analytical Instruments GmbH
& Co. KG, Kleve, Germany) was used for Ca, Cr, Cu, Fe, K, Mg, Mn, Ni and Zn
determination in digested samples. Sample introduction was carried out using a
peristaltic pump equipped with an “antipulse-head” (SPETEC, Erding, Germany),
connected to a Mein hard nebulizer with a cyclon spray chamber. The measured spectral
element lines were Ca 317.933 nm, Cr 267.716 nm, Cu 324.754 nm, Fe 259.939 nm. Mg
279.079 nm, Mn 257.611 nm, Ni 231.604 nm, Zn 213.956 nm. The RF power was set to
1400 W, and the plasma gas was 13 L Ar/min, whereas the nebulizer gas was 0.6 L
Ar/min. For quality control, standard reference materials, rye grass (ERM-CD281) and
milk powder (ERM-BB150), were digested parallel to samples and analyzed together4
with the samples by ICP-OES.
2.4. INAA measurements
2.4.1. Sample preparation
Dried and homogenized plant samples, ranging between 1.0-0.2 g. were individually
packed in polyethylene irradiation vials. CRM 1547 (peach leaves) was used as certified
reference material for checking the consistency of the measurement technique.
2.4.2. Sample irradiations and measurements
The irradiations were performed at Morocco research reactor type Triga Mark II with1 z
maximum thermal flux of (1.944x10 n.cm s ). The details of the physical parameters that
determined the accuracy and precision of INAA are shown in Table (2.2).
The packed samples were individually irradiated for 25 s at a thermal flux of
-2-1
1 -26x10lzncm"z s' 1 in order to facilitate detection of short lived radionuclides. Samples
were counted immediately for 20 min.
Other batch of weighted samples was irradiated for 4 hours to detect long lived
radionuclides. After one month cooling interval, the gamma spectrometry system
equipped with a high purity germanium detector (HPGe) was used for sample activity
measurement. The measured activity of each sample was corrected for decay and
counted for one hour. Spectral analysis was performed with Ginie2000 software.
Calculations were performed using ko-IAEA program.
26
Table 2,2. Relevant Nuclear Data for determined radionuclides
Nuclideanalyzed
RadionuclideDetected
Half lifeT1/2
} .................... * ?
Gamma ray Branching ratioenergy (keV) (%)
l b M g 2/Mg 9.45 min 1014.44 28.00 j1 i11
i_____________________________________________________________i____________________________________________________________ ;
12.36 h 1524.60 18.08j
'i
^ C r 51Cr 27.7 d 320.080 10.08i ;
” Mn 5bMn 2.58 h 846.760 | 98.851!J
59Fe 44.5 d 1099.25 56.501 ;
"39Co 5.27 Y 1173.24 99.90ii!j
~ T J C u 12.70 h 1345.77 39.00iJ1
65Zn 243.9 d 1115.55 ! 50.701j1j
4SCa ^ C a 8.7 min 3084.40 91,70i
^ S r X5Sr 64.8 d 1065.00|
33.01
27
Chapter Three
Results and discussionOne of the most important issues regarding use of medicinal herbs is their trace element and
heavy metal contents. Adequate and necessary precautions should be taken into account while
supplementing the trace elements through such medicinal plants, in order to avoid other
complications of metal toxicity accompanied with the use of these plants.
Many analytical techniques are employed for quantifying trace elements in plant samples. The
principles of such technique were varied and each has its own consideration. Some of them apply
acid digestion for the samples prior analysis, as in the case of ICP-OES. while others requires
few sample preparations steps such as INAA. The selection was based on the reliability of the
results and the practical features. For example, a method could give acceptable results, but
requires sample preparation inadequate for the number of samples to be treated. Additionally, the
choice of method was also relied on the form of the material to be analyzed. For soil, sediment
and plant, INAA had the great advantage of not requiring samples to be dissolved. ICP-OES
requires dissolved samples, with non-negligible risk of pollution and lost. Some metal oxides
were incompletely dissolved, because all chemicals could not be used.
This study compares trace element concentrations (Ca, K, Zn, Mn. Mg, Sr, Fe. Cu. Co and Cr) in
14 Sudanese medical plants determined in parallel by INAA and ICP-OES to get information on
which technique is preferable at different matrices and element concentrations. The aim is also to
provide Information about measures to avoid technique-biased results.
3.1. Quality control
In order to evaluate the accuracy of the elements concentrations measured by the two employed
techniques, certified reference materials (CRM), namely ERM-CD 281 (rye grass) and ERM-BB
150 (milk powder) were used for quality control of ICP-OES measurements. While for INAA
technique CRM 1547 (peach leaves) certified reference material was used to quality control also.
The analysis of reference samples were used to specify the best method for each of the elements
of interest in our study as well to estimate the possible relative error of each technique. From the
tables 3.1 to 3.3 INAA showed an overestimation for the most of analyzed element with an
expectation of K, Ca and Mn that showed a negative relative error. A good agreement was
recognized for all listed elements when compared with their corresponding certified values, w ith
28
an exception for Cr which showed dramatically elevation will i 5 C ! ci l < X
Zn found to be in very low quantities . its measured vaw-, sho\x o
values with relative error of amount 4.4%.
On the other hand, ICP-OES underestimated in average across ail eicmcm-
material or - 2.3% in milk powder. The deviations of specific element1: -- .n j j
4,9%. Ideally, both techniques expected to provide the same result- and m em
The slight underestimation of ICP-OES measurements is characieri/xd '
findings: the SD bars still overlap with certified mean values \ r V - . * ; V•• • : d i iV.i.!v
certification, indicating that deviations from the target values are wnau 5 : i V !
more pronounced in the rye grass CRM. which is to c o n ta in
metals as oxides or silicates than the milk powder sample Conwixcd.
< ..n o n : - ;I i r ! I ^ %
. A; ac
concentrations of the most studied elements using 1NAA could he related w i i At i i
matrix, as well as some problems at low element concentration is delected.
In conclusion, the elemental levels obtained for employed reference material s
different techniques were in agreement with their certified values, suggesting
non-destructive IN A A and destructive ICP-OES for plant elemental anaf\ S ! x
Table 3.1 Elemental concentrat ion (Mean ± SD mg/kg) o f SRM 1 547 i peac % u I
1 Element ! Measured value !mg/kg ;
Certified value mg/kg1 • 1
Ki!1
23028 i|1i
24300
Mgj
4403 !•l!i
4320
i Ca.
_____ j13594 1
.i:[
15600
Fe 239 11!|2 i 8
f .... ■ ■ i i ,Zn
|_ . _ __ 118.68
,i'1[7.9
Mn 91.87 i 98
S b*" i
\
% J<
\
Table 3.2 Elemental concentration (Mean ± SD mg/kg) of reference ERM-CD 281 (rye grass) using ICP-OES
Element Measured value mg/kg
Certified value mg/kg
Relative Error %1
1
|
B 5.5± 0.2 5.5± 0.5 0.011
1
Cr 22.7± 0.4 24.8± 1.3 -8.5 j1
1
1
Cu 9.7 ±0.2 10.2± 0.5
1 | i
i kO
Mn 77.5 ±1.1 82± 4 -5.5 !1
\1
lr
Ni 13.9 ±0.3 15.2± 0.6 -8.61
1
Zn 28.3± 0.3 30.5± 1.1 -7.2!
1i
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ J
Table 3.3 ICP-OES measurement (Mean ±SD mg/kg) of reference material milk powder (ERM-BB150)
Element Measured value mg/kg
Certified value mg/kg
Relative Error % ■
!!Ca 13760±150 13800±800 -0.3
i
K 16590±200 17000±100 -2.4!
Mg 1240±30 1260±190 -1.6 !: |
Na 4140±10 4180±190 -0.9 1J
Cu 0.97±0.02 1.08±0.06 -10.1
Fe 4.54±0.06 4.6±0.5 -1.4
Mn 0.28±0.01 0.29±0.02 -1.811
Zn 45.14±0.61 44.8±2 0.811|1___________________ 1
h
30
INAA SRM 1547
-20 - lO O lO 20 30 40 50 GO 2 0Relative Error %
Figure3.1 INAA SRM 1547 relative error %
-1 0
Figure 3.2 ICP-OES ERM-CD 281 relative error %
ICP-OES ERIV1-BB 150
-12 -lO -S -6 - 4 - 2 0 2
Relative Error %
Figure 3.3 ICP-OES ERM-BB 150 relative error %
31
5.2. Comparison of INAA and ICP-OES results
j en e ra l lv . the d i f f e r e n c e in e l e m e n t s c o n te n t o f the m e d ic in a l p lan ts is m o s t i \ . iscuix 'dw .
l i f f e ren c es in the p re fe re n t i a l a b s o r p t io n o f the p lan ts , in ad d i t io n the m in e ra l c o m p o s i t i o r
;oil in w h ic h the p la n t s are g r o w n . O th e r fac to rs tha t re la te to the v a r i a t io n s m e o n c e n t r a t
n c lu d e use o f fer t i l izers , i r r iga t ion w a te r an d the c l im a t i c c o n d i t io n s .
\ c o m p a r i s o n b e t w e e n th e t w o d i f f e re n t ana ly t ica l m e t h o d s w a s c o n d u c t e d to d e t e n m n c u
l i f fe rence in th e d e t e r m i n e d c o n c e n t r a t i o n s o f th e s e e l e m e n t s can be o b s e r v e d . A s can nc
i ' ■■ V
f • t
I V
ion a im
1 i’ V * •1 \ C i 1
sl l 1;
ab le s (3 .4) an d (3 .5) . all e l e m e n t s in the s a m p l e s w e r e d e te c te d by I C P - O f S . w h i le the results
rom I N A A s h o w e d tha t the t e c h n i q u e w a s not ab le to m e a s u r e s o m e d e m e n t s , such as ( a N t
md C r in th e s a m e s a m p l e s w h ic h the i r c o n c e n t r a t i o n s are p robab lv be low the d e te c t io n m m :
::ach e m p l o y e d t e c h n i q u e has its o w n c o n s id e r a t i o n s and a d i f f e re n t approach. , i lo w e v e r . in ordci
o rely on bo th t e c h n i q u e s the re is e x p e c ta t io n o f s o m e c o r r e l a t io n s b e tw e e n t h e r e s u l t s
tehieve th is p u rp o s e , a c o m p a r i s o n b e tw e e n ten e l e m e n t s ( d a . k . I e. \ i n . M g. Sr. / m l u. ( A
md Cr) has been c o n d u c t e d . T h e se lec t io n o f th e s e e l e m e n t s w a s d e c i d e d a c c o r d in g to th
n te r se c t io n o f e l e m e n t s d e t e r m i n e d by bo th t e c h n iq u e s .
ITie c o r r e l a t i o n s b e t w e e n the resu l ts o b ta in e d for the a b o v e m e n t i o n e d e l e m e n t s w e re e x a m i n e e
nd the o b t a in e d c o r r e l a t i o n c o e f f i c ie n t ( R d and s lo p e v a lu e s w e re d i s c u s s e d ! rom fiiiutxw (-i4
97). s tromz c o r r e la t io n w a s o b s e r v e d for all e l e m e n t s w ith h iuh c o n c e n t r a t i o n s such as (. a (R
>.92 1). k ( R “ 0 .9 0 1 ) an d M n ( R “ ^ 0 .975 ) . A l th o u g h Z n d e m e n t ton nd m a co n -d d c rah le l o w
[mounts . g o o d a g r e e m e n t b e tw e e n the t w o d i f fe ren t t e c h n i q u e s w as n o t i c e d w i th R (). o'
implying the ab i l i ty o f bo th t e c h n i q u e s to d e tec t th is e l e m e n t e f fec t ive ! ;v even ai \erv i raee
imounts
vlg e l e m e n t s h o w e d s lo p e va lue c lo sed to o n e (0 .9 0 4 ) w h i l e it is c o r r e la t io n c o e f h c i c m 1C
) .648,T h is c o n t r a d i c t i o n can be jus t i f ied bv the ab i l i ty o f bo th t e c h n i q u e s to m e a s u r e * ]
dem ent w h e n its c o n c e n t r a t i o n s w e re below 2 0 0 0 irm/ka . H o w e v e r , a b o v e t ins c o n c e n t r a t io n a
i iscrepancv b e t w e e n the resu l t s o b t a in e d bv both t e c h n i q u e s co u ld be o b s e r v e d with ratio w
ibout 1.4. as p r e s e n t e d in fm u re 3.8. f r o m the resu l ts o f r e f e r e n c e m a te r i a l s ( f a b l e s
N A A s h o w e d o v e r e s t i m a t i o n o f c o n c e n t r a t i o n o f th is e l e m e n . w h i l e K IM )l S unde res t im a te^
ts c o n c e n t r a t io n w i th th e s a m e a b s o lu te a m o u n t for IN A A .
32
Similar to Mg and Co was found to be significantly affected when it is concentration getting
lower than 0.5mg/kg (figure 3.8, 3.10). Moreover; 1NAA was not able to detect its
concentrations in some studied plants.
Regarding Fe (figure 3.9), very strong correlation (R2 = 0.992) was reported for this element
however the value of the slope was less than one (0.729).This indicating the variation between
the results obtained by the two implemented techniques for the same samples.
In this study, most values of Cu and Sr were not detected by INAA for the most studied plants
(below 3 mg/kg for Cu and 78 mg/kg for Sr), for this reason the correlation for both elements
was not conducted.
33
Table 3.4 Element concentration (Mean ^SD mg/kg) in Sudanese medicmai i i
Plant Ca Kj Zn Mn
1l
N E1
mg/kg mg/kg m g/kg mg/kg^ r ' ^ »-* ; mg/kgj 1 1 i w l\ W •, *15 , : ^< W.. s
Acacia nilotica ( L . ) 6955±5 12080+ 10.28+1 i 3.24± ; 649.3::: Z0 : r
•• • 1. .b \
-A ** V'\ ■ ; —w,,
Wild. ! \ Dei. 7,9 >
1|
1.61 ! S 1i i l f
1.2 1 44.7i1 A ^! e .. /
Acacia Senegal (L.) : 8039+2 ; 7872 ; i ! N D ND 1282±3 7S OS r\ ‘ * r
' N " *j \ ;Wild
1
.9• 1 i / -i ■> ij ; 1 1
s "S. N, j V.
Balanites aegyptiaca 751.4+ | 19100: i1 i N D ND 433.4+ ND^ /’Hi
sM ' \ . ;K ; V’•fc .
L.) Del 6.71
i . . .
1.4 :11
1 1.4 '• 4-
Cajanus cajan (L.)+ • s ! /48.2± ; 13990± 31.07+6 ! 3.57± 1026±4 ND \ i * i
; > *. N\Vlillsp 5 2•w* *
lj . . ..
! 1 - 1 s1
i j
.4 16 iV
Capsicum frutescens ■ 874.7±| 1 27430± ;| j 19.07+2 14.95+ 1795*4 ND 2 ! 8 4 ~ i J ' * *■ h_ ;T
1
- 5.8f1 ■- I ! I m ; 0.8 c ">
* r
\ s% >1 . J— \ ’
Citrullus colocynthis 602.4±1
5624+1 25.72+1 15.37± ; 2043+6 ND — , fc i ' ! ) ! -■ : i- i j > i : ^L
/.Schrad. ! 1 0 .6! •; .
i
6.5 28.9
Cucurbita maxima ' 371 .9± ! 7772±l I 73,03±3 16.23+ ' 1901 =*=2 \ 1) O ■>. ^ - " E'.S; “S , . 1
\ / \ [N. — f
w p 6.9 ! s1 11 1L | .6 N
J .8—
w ■' \ *"• » N. r
■'ymbopogon 1263+7! 6354—1 1 1.66=2=1 145.5+ 975.8+ N D 28 VS-. \D x -V .P
Aoximus Stapf. ..5• Si j ■ i1 i
| i
/ 4.8 10.5 N -v S - ■ \
- -"K
-oeniculum vulgare ] 3670± 26440± 27.92±8 83.5+1 5419±6 134.8- 28S7 -:.3 \ ! ) ' : h
’Mill 5.1 ! 1.6 !1 I
_ L .. . i
ip.r M 0.1 - O « it _ i, i
juiera senegalensis 13360± ! 9 0 8 2 + I !I ! 26.85^8 556.4+ 2 5 7 i±S N D :■ 8 . 5 - \ !) +M T ■
T.Gmel. JOi !1 S '1 — i ; 1 i |f |
.8 b
iapiophyllum tuber- 6586±4 : 14270: i 8.57+25 ND 1022+1 \ i a \D \ i
alarum ! 1.6 j! |
.9 0 . 5 18.ii
.awsonia. inermis L 10880+J
: ND !1 ' i li i: i
13.93 41.71 +i
/
2913+31
1 /
1
1 /4_a-5..6
20SNr:; 0,U
V l\ \} >
■
Cgella sativa L. ; 6 7 1 2 : 5 ; 8921+1 j 45.6+6. , 39.2+1 3806+5 ND K) 18-5 ( 'l ’ 'A . % / 's .
!i1ji
1 1 .7 ■D 5.11
|A - ■ V- j N
alvadora persica L. 8018±5j 13740+ ' ND ND : 679 .2=t 200+ iI \[) N[ •\ rV ; ; - *
.6i 1.6 1 1.7i
34
Table 3.5 Element concentration (Mean±SD mg/kg) in Sudanese medicinal plants obtained by 1CP-OES
Planti
Camg/kg
Kmg/kg
Znmg/kg
Mnmg/kg
Mg Sr Fe Cu Co Cr mg/kg 1 mg/kg j mg/kg ; mg/kg mg/kg : mg k
Acacia nilotica (L.) Willd. Ex Del.
6540±311
12200± 353
11 ±2. 0
10i 0.c6
459±2J9
77.3±5 250±9.0 ; 3±0.2 i 0.6±0. 0.6=4i ,i rAcacia Senegal (L.) Willd.
7595±79
7440±721
0.2±0.1
2±0.01
1235± | 8I.6±7 36 |
10± 1.0 1 1 ±0,1 i 0.6±(.) ' 0.6±( 1 , !
Balanites aegyptiaca (L.) Del.
850±9 16300±282
3±0.1 1.3±0. 1
519±9 .2
6.8±1 | 12±0.9 ; 1.1 ±0.1 : 0.6±0. i 0.53=1 1
Cajanus cajan(L)Millsp,
640±24
14900± 141
33±0.4
14±0.1
1040±0.01
4.7±0.81 35±1.0 : 12±0.4 I 0.5x0. ! 0.6±(1 ’ 1 11 -f
i
Capsicum frutescens L.
716±7 22300±141
17±0. 2
12±0.2
1485±35
5.3±0.911F
i _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
174±2 I 10±0.1 ! 0.5±0. | 0.5±(1 i '? ; i !1 ... f
Citrullus colocynthis (L) Schrad
505±12
4960±3a
28±4.6
15±0. 8
2070± j 2.6±0.1 1 28 !
46±5.0 | "±0.5 i 0.5±0. I 0.6=C’ 1] ! >1 ....... .. i 1 _i__ ' __Cucurbita maxima L 531±1
06860±1
1374±1.
J32±0.
13750±
423.1 ±0.1 ; I73±I3 ! 12±0. 1 ! 0.6±0.
1 il ■ 1 1 i1 i i
0.6=C
CymbopogonproximusStapf.
1170± 0.001
5950±0.001
22±5 209±10
880±12
1.1 ±0.9 \ 189-10 : 1-0.1 0.6±0.1 I: : 1l . ... ... 1 .. .. ._
0.6-tTIlFoeniculum vulgare P. Mill.
11600±112
23700±424
25±1 66±3.4
3750±84
47±1 1 2105±3I 4
11 ±0.5 : 1.1 ±0. 1 4±0.(1\A• I
Guiera senegalensisJ.F.Gmel,
10100±56
8720±85
26±2 518±3A
1995±46
47.4±2 i 534±5 ! 6±0.5 i 2.7±0.1r \\ : 1 11. 2=(
\.JtHaplophylumtuberculata
6870±261
14400±282
1 1±1 13±0. 4
763±3J
6.2±0.9 ! 82±3 i 3±0.I ! 0.6±0. ! 0.7±tf ;' 1 ; * i ; l i
Lawsonia inermis L. 13800±636
6330±197
12.5± 0.5
52±2 4070±19
269±7 259±6 ; 4±0.2 i 0.6±0. J 0.6±Ci : :. .. i . . .... i
Nigella sativa L„ 6240±23
8600±15
46±2 34±0.6
3130± 56
28.8±2 1J
695±41Ir
8±0.2 : 0.5±0. i 2=0.(!
Salvadora persica L.ii1
8350±41
13500±212
8±0.6 4±0.2 614±2J
268±4 1J
25=0.6 | 4±0.2 1 0.6--0 | 0.6±C! ij 1 M*
35
A- •
y = 1.009x
R2 = 0.921
l
)i\\*4441
i44
ii
1S
14
}4
j12
s
i<11cJ4i49
INAA........ .. .11| 111 MM1
fJ
Figure 3.4 Plant calcium contents measured by INAA and ICP-OES
30
25
20LOLU9 15O.U
10
5
0
y = 0.901x
R2 = 0.964
............ d i ^ i H i ^ i i > < i i | i i ‘ r i T i T i v d r i
Figure 3.5 Plant potassium contents measured by INAA and ICP-OES
Figure 3.6 Plant zinc contents measured by INAA and ICP-OES
3 6
Figure 3.7 Plant manganese contents measured by ! N A A and ICP-OES
6000
5000
COLXJ4000
Oia.u
3000
2000
1000
0
Mg y = 0.904x R2 = 0.648
0 1000 2000 3000INAA
4000 5000 6000■ ---------------------------------------------------------------- — . . . ^ ........pj(i p tn ~ T r»‘ y i t H V H M S k M U U i e b
Figure 3.8 Plant Manganese contents measured by [NAA and ICP-OES
2500
<
v = 0.729x R2 = 0.992
‘ m l J i l ^ J w i l i i p p i U i i i r i I m l i d i n t i l i t i l i *
3500
Figure 3.9 Plant iron contents measured by INAA and ICP-OES
37
cn
y = 0.994x
R 2 = 0 805I|
II
L
j
Figure 3.10 Plant cobalt contents measured by INAA and ICP-OBS
5
4
Q.U
3
2
1
t
y = 0.183xR2 = 0.456
♦
Figure 3.11 Plant chromium contents measured by INAA and ICP-OFS
3.3. ConclusionsBased on the results of this comparative study on elemental analysis of medicinal plants using
INAA and ICP-OES, the most concluding remarks are that:
• INAA is equally competitive method for the measurements of calcium, potassium, iron,
manganese, magnesium and zinc in medicinal plants, besides ICP-OES.
• Non-destructive nature of the INAA might give it the advantage of handling with ease
and less time consuming over ICP-OES technique.
• ICP-OES seems to be the superior technique over INAA when measuring chromium,
nickel and copper in the medicinal plants.
38
Chapter Four
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De Corte F (1987) The ^-standardization method, a move to the optimization of neutron
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De Corte F, Simonits A, De Wilspelaere A and Hoste J (1987) Accuracy and applicability of
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