dma direct mercury analyzer

Gamal A. Hamid1

DMADirect Mercury Analyzer

Gamal A. Hamid

Gamal A. Hamid2

DMA

ThanksTo everyone who has helped us with

support,

new books, hard/soft ware And over the internet

Special thanks for MILESTONE

http://www.milestonesrl.com/

Gamal A. Hamid3

DMA

Contents

• Introduction

• Hardware

• System initialization

• Software

• Analysis

• Applications

Gamal A. Hamid4

Introduction

Gamal A. Hamid5

DMA

DMA-80

• DMA which uses the principle of thermal

decomposition, amalgamation and atomic

absorption.

• The DMA-80 can analyze solid, liquid and gas

matrices with equal precision.

• All mercury is released from the sample through

thermal decomposition.

• This eliminates the need for any sample

preparation.

Direct Mercury Analyzer for analysis of liquid, solid and gaseous samples

Gamal A. Hamid6

DMA

DMA – 80 Advantage

• Results in 5 minutes.

• Results are matrix independent.

• Small footprint ideal for laboratory and

field analysis.

• No sample digestion step.

• No chemical pretreatment step.

• Eliminates use of reagents and their disposal.

• Validated results for both solid and liquid

matrices.

• Autosampler allows unattended operation.

Gamal A. Hamid7

DMA

Mercury

• Elemental mercury

• Most toxic in its vapor form, slowly vaporizes

at room temperature and more quickly when

heated.

• Organic mercury (methyl-mercury)

• Elemental and inorganic mercury salts are

transformed into organic mercury by

bacteria and it concentrates by bio-

accumulation.

• Readily absorbed in humans

• Exposure can result in long term damage to

the kidney, liver and central nervous system.

Gamal A. Hamid8

DMA

Principle of Operation

Gamal A. Hamid9

DMA

Sequence of Analysis

• Solid, liquid or gas samples are weighed and

introduced in the DMA-80.

• The sample is initially dried and then thermally

decomposed in a oxygen/air flow.

• Combustion products are carried off and further

decomposed in a hot catalyst bed.

• Mercury vapors are trapped on a gold amalgamator

and subsequently desorbed for quantitation.

• The mercury content is determined using atomic

absorption spectrophotometry at 254 nm.

Gamal A. Hamid10

DMA

Accuracy

The DMA-80 produces accurate results over a wide dynamic range and on a variety of different matrices.

Gamal A. Hamid11

DMA

Sample matrix

• The DMA-80 produces matrix independent results.

• The instrument is calibrated with aqueous standards and analyzes organic and inorganic solid samples.

Gamal A. Hamid12

Hardware

Gamal A. Hamid13

DMA

Hardware

Back View

Front View

Gamal A. Hamid14

DMA

The System

Gamal A. Hamid15

DMA

Instrument Hardware

1. Sample dosing system.

2. Thermal process furnaces.

3. Atomic absorption spectrophotometer.

4. T660 or T1660 or PC controller.

Gamal A. Hamid16

DMA

1. Sample Dosing System

• The DMA-80 has a built-in 40 positions

auto-sampler plate for high throughput

unattended operation, for solid and liquid

samples.

• This auto-sampler system is composed of a

pneumatic and an electrical section.

• Maximum sample weight 500 mg.

• Maximum sample volume 1,5 ml.

• Possibility of multiple sample dosing for Hg

pre-concentration on amalgamator.

Gamal A. Hamid17

DMA

Pneumatic Section

• Purpose of the pneumatic section is to take

the sample boat from the auto-sampler

plate, to place it in the catalyst tube and, at

the end of the sample analysis, to locate it

back on the plate.

• The movement of the pneumatic cylinders

is activated by the opening and closing of

the corresponding electro-valve placed on

the valves block.

• The position of each pneumatic cylinder is

controlled by two electrical end-run

switches.

Gamal A. Hamid18

DMA

Electrical Section

Auto-sampler motor

• Purpose of the electrical section of the

dosing system is to move, controlled by the

software, the auto-sampler plate in the

correct position for the loading and

analysis of each sample.

• It is based on a step motor with encoder

installed underneath the autosampler

plate.

Gamal A. Hamid19

DMA

Boat Types

• The samples are weighed and carried for

measurement in special sample boats be

made of Nickel or Quartz.

• To clean metal boats, it is possible to bake

out them in a muffle furnace or they can be

run without sample in the DMA-80 at 650°C

(decomposition) for 180 seconds.

• Repeat this cleaning procedure until the

absorbance is stable and lower than 0.003

running blank analysis.

Gamal A. Hamid20

DMA

2. Thermal Process Furnaces

• After the loading and positioning steps the

sample is submitted to three different furnace

systems and a thermal process with four distinct

thermal phases: drying, decomposition,

catalyzing and amalgamating.

• Heating in the furnace is produced through an

electrical resistance under the control of power

values and thermocouple sensors.

• All thermal processes are performed under

oxygen flow or air compressed with the purpose

of carrying the sample and its residuals to all the

sections, as well as to aid decomposition.

Gamal A. Hamid21

DMA

a. Drying & Decomposition

• Moisture removal from solid samples, bulk

evaporation from liquid samples and final

decomposition.

• Temperature is controlled by a thermocouple

connected to the mother board.

• If a new catalyst or amalgamator tube is replaced,

conditioning procedure has to be followed and a

new calibration curve is required.

• This process is not necessary for new DMA80 it

already done during final quality control testing.

• After drying the sample is decomposed at high

temperature (burned in the oxygen flow).

Gamal A. Hamid22

DMA

b. Catalyzing

• keep the temperature of the catalyst tube

stable at around 565°C, which is necessary

for its optimal functioning.

• Inside the catalyst tube, mercury coming

from the sample is converted in metallic

mercury and the reaction products

generated during the sample

decomposition are neutralized.

Gamal A. Hamid23

DMA

c. Amalgamator

• Hg is trapped in the amalgamator and all the other gases

are flushed out of the system before Hg is measured in

the cuvette.

• The amalgamator coil has a double purpose: to keep the

amalgamator tube at the stand-by temperature of

around 170°C/150°C and then to quickly heat it up to

850°C.

• The temperature is measured with an infrared sensor.

• The first stand-by temperature is necessary to avoid

water condensation and retain of organic residues in the

amalgamator tube.

• The grove on the quartz must be placed close to the

cuvette.

Gamal A. Hamid24

DMA

3. Atomic Absorption Spectrophotometer

• The spectrometer works with a single beam

system with sequential flow through

measurement cells.

• It is composed of:

A low pressure Hg lamp with relative

power supplier,

A cuvette system with quartz

window,

A detector based on a Si-photodiode

sensor.

Gamal A. Hamid25

DMA

Normal System

• Normal system: The spectrometer works

with a single beam system with sequential

flow through measurement cells.

• It is composed of a low pressure Hg lamp

with relative power supplier, a cuvette

system with quartz window and a detector

based on a Si-photodiode sensor.

• The cuvette block is also provided with an

heating system, controlled by thermocouple,

with the purpose of avoiding moisture

condensation.

Gamal A. Hamid26

DMA

Tricell System

• Tricell system: The spectrometer

works with a dual beam system

with sequential flow through

measurement cells.

• It is composed of an high power Hg

lamp with relative power supplier, a

cuvette system with quartz window

and two detectors based on a Si-

photodiode sensor.

Gamal A. Hamid27

DMA

Lamp

• Light source is a low pressure mercury

vapor lamp.

• The lamp is not subjected to temperature

changes and its voltage is stable in the

time.

• The cooling fan and the temperature

sensor ensure a full control of the lamp

temperature.

Gamal A. Hamid28

DMA

Cuvette “Cell”

• Cuvette system with quartz window.

• The cuvette block is provided with an heating system, controlled

by thermocouple, with the purpose of avoiding moisture

condensation.

• Clean the windows using a very soft tissue and some acetone.

• Dry them very well, in order not to left any mark on the quartz.

• Tricell DMA-80: The first and long one cuvette is used for

measuring low Hg content (up to approx. 10 ng),

• The second medium one (10-20ng), the third and short one for

measuring high Hg content (up to approx. 1200 ng).

Gamal A. Hamid29

DMA

Detector

• Detector is UV enhanced Si- photodiodes.

• Wavelength is 253.65 nm.

• Tricell system detectors.

• Normal system detector.

• Detection limit:

0.005 ng of Hg (dual-cell)

0.0015 ng of Hg (tri-cell)

Gamal A. Hamid30

DMA

4. Terminal / PC

Terminals 660 ( 1660)

• Touch-screen 6.5” (12”)with 65.000 colors; VGA resolution

640x480 for sharp process graphic.

• 5 USB port, 1 LAN connection for network, 2 RS 232 ports for

external devices, 2 video port.

• Methods and runs saved on PC-compatible USB pen-drive.

Personal Computer (minimum requirements)

• CPU Pentium III 800, RAM 256 MB.

• 20 MB free space on hard disk.

• 1 USB port, 1 CD-ROM reader, operating system Windows 7, XP

or Vista.

Gamal A. Hamid31

DMA

Oxygen / Air

Function Carrier and decomposition gas

Inlet pressure 4 bar (60 psig)

Flow rate 200 ml/minute

Purity“Research” grade

(O2 > 99,95%)

Internal oxygen pressure 3.1 bar

Gamal A. Hamid32

DMA

Flow Measurement

• The required Oxygen must have a flow rate

of approximately 160ml/minute (6-8 l/h)

and an inlet pressure of 4 bar (60 psig).

• To avoid damages to the pressure regulator

diaphragm, open the tank valve only when

the DMA-80 unit and the Terminal are

communicating, then adjust the pressure

from 0 to 4 bar.

• The internal Oxygen pressure must be set

at 3,1 bar.

Gamal A. Hamid33

DMA

Air Compressor

• Oxygen/Air connection,

• The DMA can run using Oxygen or Air with

the same pressure.

• The Oxygen or Air required for DMA-80

working must be at “research” grade (O2

/Air purity > 99,95%).

• A flow rate must have of approximately

160ml/minute (6-8 l/h) and an inlet

pressure of 4 bar (60 psig).

Gamal A. Hamid34

DMA

Mercury Trap

• Mercury trap to be located at

DMA-80 outlet.

• Activated charcoal.

• Safe operation.

• Easy and ready to install.

Gamal A. Hamid35

System initialization

Gamal A. Hamid36

DMA

Setup the System

• The DMA-80 system must be installed in a

well ventilated, dust free room, free from

acid vapors or highly corrosive chemical

atmosphere.

• Aggressive vapors can attack the system

through its ventilation openings and cause

heavy damage to the electronic boards,

plugs, etc.

• The optimal placement is in an air-

conditioned room with approx. 20 °C (± 3 °C).

Gamal A. Hamid37

DMA

Preparing the system

System initialization steps:

1. Warm up of the unit.

2. Initialization of the Catalyst tube.

3. Calibration of the unit Load one of the original .

4. Conditioning the catalyst tube.

5. Stability of 100ul of aqueous standard solution.

6. Verification of stability test.

Gamal A. Hamid38

DMA

1. Warming Up

• Click on DMA-80 Measurement icon and wait

the complete warm up of the unit.

• After approx. 15 minutes the message

“START” of the software will indicate that the

DMA-80 is ready to work.

• At this point it would be possible to install

the amalgamator.

• If a trace of condensation on the tip of the

catalyst, switch ON the unit again, wait some

minutes to remove this condensation.

Gamal A. Hamid39

DMA

2. Initialization of the Catalyst tube

Create a new working method (sample path and temperatures) in according to the

information you can find in the table.

Gamal A. Hamid40

DMA

3. Calibration

• In the calibration page load the

original calibration of the unit

performed during the QC of the

instrument.

• You can find the file saved in the

USB key or CD-ROM (calibration).

• If any calibration is not selected the

analysis can not start.

Gamal A. Hamid41

DMA

4. Conditioning the catalyst tube

Proceed with this method:

• 2 times B/V amalgamator

• 3 boats without boats

• 1 boat flour 0,3g + water 50µl

• 2 boats without boats

• 1 boat flour 0,3g + water 50µl

• n° blanks without boats (it must give an

absorbance value, (height) < 0,0030 in cell

1).

• If the conditions above are not verified it

is necessary to run further cleaning.

Gamal A. Hamid42

DMA

5. Stability of 100ul of aqueous standard solution.

• The solution (100 µl of 100ppb) must be fresh

and stabilized with 1-2% of HCL(ultrapure).

• Create a new working method

1) 00:00:10 200°C

2) 00:01:00 200°C

3) 00:01:30 650°C

4) 00:01:30 650°C

• Max start: 250°C

• Purge time P: 60 s

• Amalgamator heating time H: 12 s

• Signal recording time R: 30 s

• Use this method for the test that will follow

• Go to Meas. Page and press the white paper to

create a new measurement file and save it as

“stability”.

• Quartz sample boat required.

• In case of metal boats usage, they must be

deeply cleaned before to run a stability test.

Gamal A. Hamid43

DMA

6. Verification of stability test

• Once the analyse has ended, you have to verify:

• The absorbance values (Height) are between 0,4200

and 0.5700.

• Select all samples (green circle) in order to verify the

correct value of RSD(% error between selected

readings). It must be <3%.

• If one of this conditions is not verified, try to run the

test again.

• If both conditions are verified, then the test is passed.

• Now, it is possible proceed with the calibration of the

unit if the customer needs or start to work with the

original calibration.

Gamal A. Hamid44

Software

Gamal A. Hamid45

DMA

EasyCONTROL Software

• Evolution of previous Windows™ based

DMA-80 software.

• Selectable calibration algorithm.

• Virtually unlimited memory for programs

and actual data storage.

• Built-in service and diagnosis functions

• CFR-21 part 11 compliant.

• All sample parameters, including furnace

temperatures, method profiles, absorbance

signals, results , and calibrations are saved.

Gamal A. Hamid46

DMA

Desktop

Item Symbol Function

Dma-80 Measurements

The actual control program

Balance Set-up The communication settings for the balance. These must be adjusted only when switching over to a new type of balance.

History Trail All changes in the system are automatically documented, e.g. login, logout, etc

Panel Administration This area is dedicated to the basic adjustments/settings and to the user administration. The basic settings to a major extent are reserved to Service.

Logout With Logout you go out of the system. The Login window appears where the next user can log in with his own password.

Gamal A. Hamid47

DMA

DMA - 80

DMA-80 MEASUREMENTS

• The actual control program is opened.

• This is divided into four main registers.

1. Method

2. Calibration

3. Measurement

4. System

Gamal A. Hamid48

DMA

1. Methods

• To create a new method its Program

steps must be defined, as well as the

related parameters (temperature,

heating ramp, decomposition time,

amalgam heating time, purge time of

the process.

• Here methods can be created, stored,

changed, deleted and loaded.

Gamal A. Hamid49

DMA

Method Symbols


Create new file Provides a new, empty file

Go back Go back to the start screen, save any changes before quitting.

Break Terminated without saving and the input window is quitted.

Delete File is deleted.

Start If there is a sand clock on, this means that a Current procedure must first be accomplished (e.g. Heating of furnace and cuvette).

Stop The current measurement is interrupted and the sample boats are taken back to the auto sampler tray.

Restart The stop-button must then be re-set Touching the red-green stop-button.

Gamal A. Hamid50

DMA

Method parameters

No. Function Meaning

1 Steps 1-2 Drying time 00:00:10 to 00:02:00

2 Steps 3-4 Decomposition time 00:0 0:10 to 00:04:00

3 Max. Start-T Measurement starts only when temperature T1 (drying- unddecomposition furnace) is under the maximum Start-Temperature.

4 Purge time The time elapsing between the end ofdrying/decomposition and the start of the Hg measurement.

5 Amalgam Heater Time The time required by the amalgam heater to completely release the Hg collected in the absorption cell.

6 Recording Time Time for Noted and evaluated the measuring signal of the spectrometer.

Gamal A. Hamid51

DMA

Parameters ranges

STEP TEMPERATURE RANGE

TYPICAL TEMPERATURE TIME RANGE TYPICAL TIME

Drying 20-300°C 200°C 0-300 s 60 s

Decomposition 500-1000°C 650°C 0-420 s 180 s

Catalyst 550-650°C 565°C 0-420 s 180 s

Amalgamator 850-950°C 850°C 0-30 s 12 s

Gamal A. Hamid52

DMA

2. Calibration

• Purpose is to administer the calibration files.

• From a calibration file you can select the

used measuring points and specify the

regression curves for each cuvette.

• Different calibration files can be opened,

created and saved.

• All cuvettes are always used for

measurement.

• If the maximum peek of the first signal is

over 1.0 A (standard setting), the maximum

of the second signal will be used to calculate

the result.

Gamal A. Hamid53

DMA

Calibration Symbols


ΔE or δ Hg Value by which the measured value deviates from the calibration curve

The R² Is calculated from the deviations of the measured values that have been calculated

Zero point setting

The curve is placed across the zero point

Ultratrace range

The calibration curve can be adapted to measuring for ultratrace analysis.

Calibration methods

It is possible to determine the type of calibration curve. If „undefined“ is selected, then only the measured points will be shown and not curve.

Gamal A. Hamid54

DMA

Cell 1

Low value used for 1st cell

calibration 0 – 35 ng.

• The working standards solution

must be freshly prepared before

every calibration.

• Diluted liquid standard solution

can be stored for one month if

maintained in its original tightly

sealed bottle away from sunlight

and intense sources of radiation,

in a refrigerator at 10°C.

Standardsolution

From 5 ppmin ml

HCl 36% in ml

Deionizedwater in ml

Blank 0 1 Up to 100

0.05 ppm 1 1 Up to 100

0.1 ppm 2 1 Up to 100

0.2 ppm 4 1 Up to 100

0.3 ppm 6 1 Up to 100

Gamal A. Hamid55

DMA

Cell 2

High value used for 2nd cell of

calibration35 – 600 ng.

• Stock solution of 1000 ppm (1mg/ml)

of HgCl2 stabilized in diluted HCl.

• Standard for atomic absorption.

• Stock solution of 1000 ppm can be

stored for one year if maintained in

its original tightly sealed bottle away

from sunlight and intense sources of

radiation, in a refrigerator at 10°C.

Standardsolution

1000 ppmin ml

HCl 36% in ml

Deionizedwater in ml

1 ppm 0.1 1 Up to 100

2 ppm 0.2 1 Up to 100

5 ppm 0.3 1 Up to 100

Gamal A. Hamid56

DMA

3. Measurement

• The extinction process can be monitored in

real time.

• Previously measured data can be recalled

and displayed at any time.

• Results and statistics (over selected data)

are calculated and can be printed out.

Gamal A. Hamid57

DMA

Measurement Symbols


Add data A new line is added to the table.

Simple mode Each sample is measured individually. Each measurement has to be manually started.

Automatic mode Samples are automatically measured in sequence one after the other.

Only one sample Only a defined maximum volume can be loaded into the sample boat.

Concentrate over several samples

With the concentrate function a large sample can be distributed and measured in several sample boats.The divided samples are thermally decomposed and the total Hg of all subsamples is collected successively in the amalgamator.

Gamal A. Hamid58

DMA

Sample

• Sample name, The Name is taken over from the selected record and can be changed/modified.

• Pos, Consists of two numbers: If Simple sample processing is activated, and a sample is added,

the number over the selected record will be taken, alternatively the sample can be selected

(from pos. 1 to 40), as in this operating mode each sample can be measured individually.

• n, the number of samples.

• Amount , A weight must always be entered.

• Remarks, It is possible to enter comments on the corresponding samples.

Gamal A. Hamid59

DMA

Links

In this Register you can select the calibration file (Cal-Date) and Methods to be used for the

process.

Gamal A. Hamid60

DMA

Signal

• On the left of the screen there is a

listing of the samples.

• If one sample is check-marked, its

curve is shown in the graphic on the

right.

• Each measurement is shown in real

time and can be observed during

process run.

• During a current measurement you

can also look at earlier runs.

Gamal A. Hamid61

DMA

Signal “peak” testing

• Check the signal for a typical good

peak:

• The shape of the peak is regular

• The distance between Peak Cell 1

and Peak Cell 2 is between 11 to 15

seconds.

• In this picture: T2 (21,85s) – T1

(6,85s) = 15 seconds

• Remember, Oxygen flow rate is

from 5 to 8 L/h.

Gamal A. Hamid62

DMA

System correct profiles

Gamal A. Hamid63

DMA

Results

• The average final result with the relative standard deviation is shown in the headline of the

multiple measurements. Individual values can be disabled removing the sigma sign.

• Hg [ng], Absolute quanty of Hg in the sample (calculated from active calibration) c[μg/kg] or

c[mg/kg],Concentration of Hg in the sample (calculated from active calibration and sample

weight).

Gamal A. Hamid64

DMA

4. System

Here the system is supervised (Autosampler, heating elements, spectrometer)

Gamal A. Hamid65

DMA

Startup conditions of the system

After the start of the system all Standby functions are activated:

• The Hg lamp of the spectrometer is switched on

• The catalyst tube is locked by the pneumatic cylinder.

• Oxygen flushes the catalyst, as long as there is gas pressure.

• Catalyst, amalgamator unit and absorption cells are heated up to Standby temperatures.

• After reaching these temperatures the Start button is released.

• HEATING 1: for drying and decomposition of the sample. Here also the oxygenation takes place.

• HEATING 2: Heating of the catalyst zone at constant temperature.

• HEATING 3: Heating of the amalgamator: at constant temperature to prevent separation of

condensation water. Heating to high temperature is then used to release very rapidly the

accumulated Hg.

• HEATING 4: Heating of the cuvette block at constant temperature, to avoid condensation.

Gamal A. Hamid66

Analysis

Gamal A. Hamid67

DMA

Tips and Techniques 1

• Working range: from 0.05 ng up to 600 ng absolute value of Hg.

• That means for 100 mg of sample, 0.5 ppb up to 6 ppm.

• Eliminate any source of contamination coming from environmental dust or from the

samples.

• Cleaning boats—in the DMA-80 or a muffle at 800°C for a few minutes.

• Clean the laboratory tools such as spatula, balance plate, tweezers, etc.

• The working standards solution must be freshly prepared before every calibration.

• Stock solution of 1000 ppm can be stored for one year if maintained in its original tightly

sealed bottle away from sunlight and intense sources of radiation, in a refrigerator at 10°C.

• Note: It is recommended to measure liquid samples only in Single mode using metal boat.

Gamal A. Hamid68

DMA


• Diluted liquid standard solution can be stored for one month.

• The curve comprises the entire range of interest, working range 0.5– 600 ng.

• The quality of the calibration curve can be also improved by using quartz boats,

because quartz is completely inert.

• A method blank is prepared by using a volume or weight of reagent water at the

volume or weight specified in the preparation method.

• For solids (special for inorganic matrix), it is extremely important to have

homogeneous distribution of mercury and uniform sample sizes with a maximum

particle size of 100 um.

• Quartz boat are completely inert; they have no memory effect, and do not interact

with the acid used for stabilizing the samples.

Gamal A. Hamid69

DMA


• Increase the decomposition time will reduce the memory effect.

• Increase the recovery from difficult inorganic sample matrices, such as metal oxide, by

increasing its decomposition temperature and time.

• Reduce the drying temperature and extend the time if strong exothermic reaction

persists.

• Use pre-concentration step to increase signal of low Hg amount.

• Longer drying step allows a pre-combustion of sample before rapid decomposition at

high temperature, reducing the exothermic reaction.

• With liquid samples, metal boats can be used only in single mode, to minimize the loss

of mercury due to chemical interaction between the acid matrix and the metal boat.

Gamal A. Hamid70

DMA


• Drying time (sec) = Sample Volume (μL) × 0.6 or

• Drying time (sec) = Sample weight (mg) × 0.6 x % H2O.

• For dry inorganic samples, Drying time =10 sec

• Drying temperature = 200°C for most samples.

• Reduce the drying temperature if you are working with flammable sample

• Decomposition time is 3 min. for most samples.

• Increase decomposition time if analysis resulted in high RSD (> 5 %)

• Add 30 sec and analyze samples determining RSD again.

• For Example, coal requires 300 sec(for others see application notes).

• Decomposition temperature = 650°C for most samples

• Purge time is 60 sec for most samples

Gamal A. Hamid71

DMA

Standards Preparation

• To calibrate the instrument for its full

range, prepare 5 ppb up to 10 ppm Hg

working standards.

• Don’t leave the solution bottles open on

the bench and at the end store them into

a fridge at 5-10°C.

• The instrument does not have to be re-

calibrated every time, but the calibration

curve must be checked every morning

prior to analyze unknown samples.

Working standard (ppm) = Stock solution (ppm) x (Volume of the stock solution (mL) Total volume (mL).

Gamal A. Hamid72

DMA

Different preparation techniques

Different volumes of same standard solution

• 1 ml of 1000 ppm in 100 ml measuring 10 ppm

• 1 ml of 10 ppm in 100 ml measuring 100 ppb

Different volume of this solution (100ppb) and put it in 100 ml

measuring flask will give different concentration:-

( 50 μL, 100 μL and 200 μL) give ( 5 ng, 10 ng and 20 ng mercury).

Same volume but different standards solutions (most used)

• 1 ml of 1000 ppm in 100 ml measuring 10 ppm

• 0.5 ml of 10 ppm in 100 ml measuring 50 ppb

• 1 ml of 10 ppm in 100 ml measuring 100 ppb

• 2 ml of 10 ppm in 100 ml measuring 200ppb

Same volume (100 μL) of above 3 solutions in three 100 ml measuring flask gives

different concentrations ( 5 ng, 10 ng and 20 ng mercury).

( 50 μL, 100 μL and 200 μL) give ( 5 ng, 10 ng and 20 ng).

Gamal A. Hamid73

DMA

Working ranges

For solids and liquids Automatic switch-over.

Dual-cell:

Low range: 0 to 20 ng.

High range: 20 to 1500 ng.

Tri-cell:

Low range: 0 to 10 ng

Medium range: 10 to 20 ng.

High range: 20 to 1500 ng.

• Use 0.5 % - 5 % (1 % suggested) dilute

hydrochloric for the dilutions.

Gamal A. Hamid74

DMA

Sample Amount

• The instrument is calibrated using aqueous

standards and then analyzes organic and

inorganic solid samples.

• One method is used to analyze a variety of

different matrices .

Up to 1,5 grams of solid,

1,5 mL of liquids

0.05-100 l. of gas can be analyzed.

• For solid sample, we need to reduce the

sample’s particle size to a powder form,

normally below 100 um.

Gamal A. Hamid75

DMA

Rapid determination of Hg in Samples

Gamal A. Hamid76

DMA

Gas Analysis

• Simply sample the gas, through a dedicated

mass flow controller, using the Sorbent

Traps, and load them onto the DMA.

• Total mercury (elemental and oxidized

forms) is quantitatively measured in 5

minutes.

• Sorbent Traps are reusable and extremely

easy to operate.

Gamal A. Hamid77

DMA

Gas sample collection

• More adsorption tubes can be tied up,

according to requirement.

• With two adsorption tubes, the sample gas

is collected on the first tube, while the

second is used to control the blank value.

• Upgrading kit for direct mercury

determination at trace level in gases.

Gamal A. Hamid78

DMA

Sample measurements 1

• Switch on the DMA-80 System it requires approx. 15 minutes of pre-heating time before run.

• Open the “Methods - parameter”, type a new method name, description and assign the working

parameters of the instrument, such as drying and decomposition time and save the new method

file.

• Open the “DMA-80 Measurement - sample ” click the button to obtain a new empty data file, type a

new data name, number of sample and weight, description and save new data file, Select the

operating mode, either automatic or simple.

• Open the “DMA-80 Calibration”, click the button for provide new empty calibration file, type a new

data name, description and save the new calibration file.

• Return to the “DMA-80 Measurement ”, and load the data file saved. Open “Sample” table of

“Data”. Click “magic wand” button to build a new line, fill the data.

• Open “ Measurement - Result” table and clicking the “Calibration” button appears under State “C”.

Enter with the concentration of your working standard solution.

Gamal A. Hamid79

DMA

Sample measurements 2

• Carry on an blank (several empty boats) measurement to make sure that the system is free

from Hg contaminations, (this cleans the system and the boats).

• Then, follow the calibration procedure that has been described above, running one of the

clean empty boats. In the “Result” table, enter 0.0000 in the “C (μg/Kg)” column and 0.1 g in

the “Weight” column.

• Check calibration of the system measuring a reference sample. At the end also the signal

curve can be tested in the Measurement/Signal menu.

• Add the data necessary for the measurement. Be careful that measurement can be started

only when weight is indicated for all data records.

• Enter the sample weight, put the sample in the Autosampler and start measurement.

• Verify the results, If the samples show heavily different Hg values, it is recommended to carry

out blank measurements after samples with high values.

Gamal A. Hamid80

DMA

QC during analysis

• An initial calibration verification standard is checked once per run after calibration.

• An initial calibration verification blank is checked once per run after calibration.

• Verification standard for instrument calibration and standardization:

• checked every 10 samples and at end of run.

• A method blank is analyzed with each sample batch, or one per

20 samples (5%), for each matrix.

• An external reference sample (laboratory control standard) is analyzed with

each batch, or one of 20 samples (5%) for each matrix.

• A matrix spike is analyzed with each sample batch, or one per 20 samples (5%)

for each matrix.

• A sample in replicates (spike in replicates) is analyzed with each sample batch,

or one per 20 samples (5%), for each matrix.

Gamal A. Hamid81

DMA

Acceptance Criteria for QC

• Control standards for checking the stability of the instrument

calibration within ±10% of their true value.

• blank should be less than 10% of the lowest sample

concentration for each analyte.

• The acceptable criteria in absence of historical analysis is set at

±10%.

• Matrix Spike/Matrix Spike duplicated at ± 20% of the spiked for

precision and ≤ 20 relative percent difference.

• For samples processed, The acceptable criteria in absence of

historical analysis is set at ±10%.

Gamal A. Hamid82

Applications

Gamal A. Hamid83

DMA

Major Applications

• Biological

Blood, urine, hair, tissue, plankton

• Liquids

Waste water, crude oil, heavy oil, detergents, paints

• Solids

Coal, fly ash, soil, sediment, sludge, minerals, food, feed,

plastic, wood, vegetables, leaves, waxes

• Medicinal

Pharmaceuticals, gelatin capsules, lipstick, lotions

• Gas

natural gas, biogas, gases processing, safety and health

occupational hygiene, hazardous waste inspection

Gamal A. Hamid84

DMA

Application Book

• Clinical, 6 applications .

• Chemicals, 8 applications .

• Beverage, 4 applications .

• Cosmetic, 4 applications .

• Environment, 14 applications .

• Foods, 29 applications.

• Pharmaceutical , 11 applications .

• Petroleum, 10 applications .

• Geochemistry, 25 applications .

• Industrial, 3 applications .

• Energy, 1 applications .

• Plastic, 20 applications .

Gamal A. Hamid85

DMA

DMA Selection

Gamal A. Hamid86

ThanksGamal A. Hamid

dma direct mercury analyzer

Education