Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

इंटरनेट मानक

“!ान $ एक न' भारत का +नम-ण”Satyanarayan Gangaram Pitroda

“Invent a New India Using Knowledge”

“प0रा1 को छोड न' 5 तरफ”Jawaharlal Nehru

“Step Out From the Old to the New”

“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan

“The Right to Information, The Right to Live”

“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam

“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 1832 (1978): Specification for Malathion, Technical [FAD1: Pesticides and Pesticides Residue Analysis]

Gr4

IS : 1832 • 1978( Auftlrrned 1117)

Indian StandardSPECIFICATION FOR

MALATHION, TECHNICAL

( First Revision)

Fourth Reprint JANUARY 2001

UDC 632.951 MAL

C Copyright 1978

BUREAU OF INDIAN STANDARDSMANAK BHAVAN. 9 BAHADUR SHAHZAFAR MARG

NEW DELHI 110002

July 1978

xxx2007

AMENDMENT NO. 1 JANUARY 1980TO

IS I 1832-1978 SPECIFICATION FORMALATHION, TECHNICAL

(n-« Re"i,ion )

AlteratioDs

(Pages 6, 7, 8 and9, clauses A-I to A-l.6.2 ) - Substitute the follow­ing for the existing clauses:

'A-I. PRINCIPLE OF METHOD

A-I.I Malathion, S-I, 2-di ( ethoxycarbonyl) ethyl 0, O-dimethylphosphorodithloate, is decomposed by alkali in ethyl alcohol or methylalcohol to sodium 0, O-dimethyl dithiophospbate sodium fumarate, andethyl alcohol. The sodium 0, O-dimethyl dithiophosphate is then conver­ted to the cupric complex which is soluble in carbon tetrachloride withthe formation of an intense yellow colour. The colour intensity is propor­tional to the concentration of 0, O-dimethyl dithiophosphoric acid and ismeasured colorimetrically at 420 om, the absorption peak. The corres­ponding amount of the insecticide is derived by comparison with astandard prepared with a known amount of the pure insecticide, which issimultaneously carried through the procedure.

A-I.I.I In this method, ferric reagent is added to oxidize materialswhich would reduce cupric ions to cuprous ions; with 0. O-dimeth~'1

dithiophonic acid (DMTA), cuprous ions form a colourless complexwhich is apparently more stable than the yellow cupric complex.

A-I.2 Apparata.

A-l.2.1 Spectrophotometer or Photoelectric Colorimeter- with a blue filter(420 om ) and having l-cm absorption cell.

A-I.3 RealeDt.

A-I.3.l Malathion

A-l.3.2 Acetonit,il, - boiling range 80 to 82°0.

A-I.3.3 Ella]1 Aleohol - anhydrous. alternatively methyl alcoholanhydrous may be used.

1

A-t.3.4 Carbon Tetrachloride

A-I.:J.5 Sodium Hydroxide Solution - 0·5 N. Dissolve 4-0 g of sodiumhydroxide in 200 ml of water to get a clear solution.

A-l.3.6 Ferric Reagent

A-I.S.G.I Stock Solution - Dissolve 4·0 g of ferric chloride (FeCls6H.O) and 160 ml of concentrated hydrochloric acid in water and diluteto 500 mi.

A-l.3.6.2 Dilute solution - Dilute 25 ml of the stock solution withwater to 1 000 ml,

A-I.3.7 Copper Sulphate Solution - 1·5 percent (m/v) • Prepare bydissolving 1·5 g of copper sulphate (CuSO•.5H.O) in 100 ml of water.

A-l.4 Preparation of Standard and Sample SolutioDa

A-I.ti.O It is very important in preparing the Standard and Sampl,Solutions that volume fluctuations with changing temperatures are avoided.This is accomplished by bringing each solution to the volume mark justbefore proceeding to the next step in the procedure, as indicated or pre­ferably analysis shall be carried in a room maintained at constanttemperature.

A-I.ti.l Preparation of Standard Solution

A-I.f.t.! Accurately weigh into a 5-ml or lO-m! beaker, 0·100 ±o020 g of pure malathion. Quantitatively transfer it to a 100-ml volumet­ric flask with anhydrous ethyl alcohol or anhydrous methyl alcohol.Then dilute with ethyl alcohol or methyl alcohol to approximately5 ml below the volume mark. Allow the solution to come to a selectedtemperature. Record this temperature. Dilute the solution with corres­ponding alcohol to the mark and mix well. Call this as Standard Solution A.

NOTE - Standard Solution A may be retained for daily use up to t,,'o weeks. Itshould be preferably kept at Jow temperature. It is very important, however, thatit is adjusted to the temperature recorded above before allquots are withdrawn.

A-l.4.1.2 Transfer a 10 ml aliquot of Standard Solution A into a100-ml graduated flask. Add 1 ml acetonitrile and dilute with corres­ponding alcohol to approximately 5 ml below the volume mark. Retainthe solution until Sample Solution (se, A-l.4.2) is prepared and is readyfor final dilution. At that time, dilute with corresponding alcohol to themark and mix well. Call this as Standard Solution.

A-l.4.2 Preparation ofSample Solution

A-l.4.2.1 Accurately weigh a quantity of the sample containing0·100 ± 0·020 g of malathion and quantitatively transfer it to a lOO-ml

2

volumetric flask with anhydrous ethyl alcohol or anhydrous methylaleohol and make up to the mark with corresponding alcohol at selectedtemperature ( see A.l.4.1.1). Call this as Sample Solution A.

A-l.4.2.2 Immediately transfer a 10 ml aliquot of Sample Solution Ainto a lOO-ml graduated flask. Add 1 ml acerenitrile and dilute it tomark with corresponding alcohol at selected temperature (stt A-I.f.I.1 )at the time of final dilution. Call this as Sample Solution.

NOTE - If more than one sample solutions are being prepared Cor assay, thenall SampleSolutions and the StandardSolutions should be diluted to approximately 5 mlbelow the volume mark as prepared. All shall be diluted to the volume mark at thesame time.

A-l.5 Procedure

A-I.S.O To obtain accurate results, it is important that the analysis ofStandard and Sample Solutions be carried simultaneously through the proce­dure given in A-I.5.t to A-I.5.4 without interruption.

A-I.S.I Transfer a 15 ml aliquot of Standard Solution and 15 ml ofSample Solution to two different 250-ml separating funnels. Add 2 ml ofsodium hydroxide solution and mix well by swirling gently (do notshake) for 5 to 10 seconds. Allow the solution to stand for exactly2 minutes.

A-J.5.2 Immediately add 75 ml of ferric reagent and mix well byswirling for 10 seconds. Allow the solution to stand for exactly5 minutes. During this 5 minutes period, fill two 50-ml volumetric flasksto the mark with carbon tetrachloride and after the lapse of 5 minutessimultaneously transfer the carbon tetrachloride from each volumetricflask to the respective separating funnels. Allow the flask to drain forone minute.

NOTE - From this point onward the Sample Solution and Standard Solution shouldbe handled separately. Carry each one through the next step without interruption.

A-I.5.3 Add 2 ml of copper reagent. Start shaking the separatingfunnel immediately after addition of copper reag-ent for exactly oneminute. The copper complex of DMTA is unstable in the aqueousphase. The copper reagent should be added with a fast delivery pipetteand the shaking should be started with practically no time lapse. Allowthe phase to separate. Allow some solvent phase to rinse the stem of theseparating funnel, then run the clear solvent phase directly into the cell.

A.I.5.4 Measure the absorbance of the yellow solution within 2 minutesat 420 nm using carbon tetrachloride as the blank.

NOTE - Absorbance measurements of both Standardand SampleSol,lIions should bemade at the same fixed time after the end of the shaking period. The yellow colourof the copper complex in carbon tetrachloride is unstable, hence the colour shouldbe read within 2 minutes after extraction. During this time the absorbance readingdrops very slowly.

3

A-I.a Calc.doa

A-I.S.I The absorbance measurements of the Standard and SampllSolutioftslhould agree within ± 10 percent of each other.

A-l.6.2 Malathion content, percent by mass... ~ X -iT X f

where

.A == absorbance of SamjJl, Solution at 420 nm,m - mass in g of pure malathion taken for the preparation of

Standard Solutio",f - percentage purity of the malathion used for the preparation

of Standard Solution,B .. absorbance of Standard Solution at 420 nID, andM - mass in g of the material taken for the preparation of the

Sampll Solution. '

(Pill' 10, claus, A-2.3.4 ) - Substitute the following for the existingclause:

'A-2.3.4 Alcoholic SocIiUlD Hydroside SolutioD - 1 N.'

ePag, 12, clauses B-3 to B-3.2) - Substitute the following for theexisting clauses:

'B-3. DETERMINATION OF PURITYB-3.1 Preparation or Perchloric Acid - Dissolve i3 g of 70 percentperchloric acid with 124-1 g of acetic anhydride and dilute to 5 litreswith glacial acetic acid.

NOTJI - If the acetic acid used is not anhydrous, a corresponding larger volumeof acetic anhydride will be required, equivalent to the total water content of theother two reagents_

B-3.2 StaadardlzatloD of Perchloric Acid - Dissolve 0·2 g of anhy­drous sodium carbonate, accurately weighed, in 50-ml of glacial aceticacid and titrate this solution with the perchloric acid solution, using1 percent .-naptholbenzcin solution in benzene as indicator. 0-200 g ofsodium carbonate corresponds to 37-73 ml of O'] Nperchloric acid.

B-3.3 DetermiaatioD of Purity 01 the Sample - Dissolve 0-300 g ofthe salt in 25 ml of glacial acetic acid and titrate against 0-1 N perchloricacid, potentiometrically (see B-3.2 ).B-3.4 Calculate the percentage purity of the salt, The purity obtained bythe method is greater than 99 percent.'

(AFCDC 6)

4

AMENDMENT NO. 2 OCTOBER 1980TO

IS 11832 ·1978 SPECIFICATION FORMALATHION, TECHNICAL

(n-« Revleion }

AlteratioDs

[ Page 7, claus,A-I.:J.! (see also Amendment No.1) ] - Substitutethe following for the existing clause:

c A-l.3.1 Malatkion - pure of + 98 percent purity by GLC or colori­metric method. •

[ Pag, 9, claus« A-l.6.2 ( se, also Amendment No.1) ] - Substitutethe following for the existing formula:

'A-l.6.2 Malathion content, percent by mass,if GLC reference material( ", A-l.3.1 ) has been used

OR

Malathion content, percent by mass,if colorimetric reference material(see A-l.3.1 ) has been used

(AFC1DC 6)

A m-=--x - X ItB M

Pnnted at New India Pnntlng Press. KhurJB. IndlB

IS I 1832 • 1978

Indian StandardSPECIFICATION FOR

MALATHION, TECHNICAL

( First Revision)Pest Control Sectional Committee, AFCDC 6

ChairmanDR S. N. BANERJEE

R,pr,s,ntin,Directorate of Plant Protection, Quarantine at

Storage ( Ministry of Agriculture & Irrisation ),Faridabad

Department of ARriculture, Government of UttarPradesh, Lucknow

DB N. K. BA8U

DR S. R. BARoo~H

Pesticides Association of India, New DelhiCentral Forensic Science Laboratory, Central

Bureau of Investigation, New DelhiPesticides Formulators Association of India

( S. S. I. ), BombayAlkali & Chemical Corporation of India Limited,

CalcuttaDn. T. V. n.AUHUltAMAN ( Alurn u« )

DR A. K. BHATNAO ~R I-hndustan Insecticides Limited. New DelhiSHIll c. c. ABRAHAM ( Altemat« )

SHRI V. G. DE8BPANDE Ciba-Geigy of India Limited, BombaySJIlU E. A. ALMEIDA ( AII,rnat, )

SaRlO. P, DtlAMIJA Export Inspection Council of India, New DelhiSURI P. K. CHATTERJ~B (Alt,r"a!, )

Dn M. S. Dn.\'l'T National Malaria Eradication Programme, DelhiDllt.Jl:OTOR Cilt:NlCRAL ARilED Directorate General of Armed Forces Medical

FORCES MICOJ('AL SERVIC1':S Services ( ~linistry of Defence ), New DelhiR ll: A R-AuMIRAL M. S.

MALHo'rRA ( Alt,rraat, )DIRECl'OI\ OF AORU·ULTURB

M,mb,rJDR N. S. AOARWAL Department of Food ( Ministry of Agriculture at

Irrigation ). New DelhiDR K. KRJ8HNAMURTilY ( Alternat« )

DR P. N. AOARWAL Ministry of Defence ( R&D)DI\ N. P. RAO ( Altemat« )

SRnl H. S. B\lfLDR H. L. BAMI

DEPUTY DIREC'rQR (PLANTPROT..;CTIt)N ( 1I.11,,,,at, )

( Con'ia,tl , .. ~al' 2 )

@ Copyri,h' 1978BUR)~AU ()F INDIAN STANDARDS

This publication is protected under the Indian Copyright .A." (XIV of 1957) andreproduction in whole or in part by any means except with written p~rmiSlionof tbepublisher .ball be deemed to be an infrinlemeD' or copyright under the said Act.

IS 11832 ·1978

( Cuntinu,dfrom pag, 1 )

M,m6"sDRUOS CONTBOLLBB ( INDIA)

Rtpr'l,mingIndian Pharmacopoeia Committee (Ministry of

Health &. Family W~lfare ), New DelhiSHRI M. RAVIKANT ( AII,rnal, )

SHRt G. D. GOKBALE Bombay Chemicals Private Limited, BombaySHRI V. V. KETKAR ( Alt"""t, )

JOINT DJRECTOR Oll' AORICULTUBE Department of Agriculture, Government of( DEvELoPM~~NT &. lOP) Karnataka, Mysore

DEIJUTY DIRECTOR Oll' AORI-CULTURE (PLANT PROTEC-TION ) ( AlI,rnat, )

DR R. L. KAI.RA Punjab Agricultural University, LudhianaDR R. P. CUAWLA ( Alumat« )

DR KI8RAN SINGH Indian Institute of Sugarcane Research ( ICAR ),Lucknow

DR S. c. SRIVASTAVA ( Alt,rnat, )SHRI S. G. KUI81lNAN National Organic Chemical Industries Limited,

BombayDR J. S: VER&IA ( Alt,rnal, )

SUBI S. K. MAJUMDAR Central Food Technological Research Institute( CSIR ), Mysore

DR K. S. SINGH

DR K. D. SHARMA.

DB N. K. Roy ( Alurnat« )DR K. D. PAIIABIA

SURI M. MUTBU ( Alt,rnat, )SaBI K. S. MEHTA Bharat Pulverising Mills Private Limited, Bombay

SHR1 S. CHATTKRJI ( Aiternlll,)DR A. L. MOOKERJEK Cyanamid India Limited, Bombay

SHRI J P. PABtK1I ( AlI,rnal, )DB S. K. MUJCERJEK Agricultural Chemicals Division, Indian Agricultural

Research Institute ( leAR ), N<.-w Delhi

Central Insecticides Board. Directorate of PlantProtection, Quarantine & Storage ( Mjni~try ofAgriculture & Irrigation) Faridabad

DR S. Y. PANtlIT Bayer ( India) Luuired , Bunlb'aySURI D. N. NAKHATE ( Alt,rnal, )

DR T. N. PAR'fSA8.'BATBY Regional Research Laboratory ( CSIR ), HyderabadSUBI AI. A. PA'!'}~L Department of Agrtculture, Government of Gujarat,

AhmadabadRallis India Limited, BombaySHRIY.A.PRADBAN

DRZ. J. KAPADIA ( .4lt,rfUJ/, )DR F. RAJllUAN Tea Research Association, Calcutta

DR G. SATYANARAYAMA. ( Alt,rnat, )SIlBI G. K. RAO Ministry of Defence ( DGI )

DH A. K. SEN ( Alt,rn,,,, )SHRll<. R. NARAYANA RAO Food Corporation of India, New Delhi

SliT K. K. M. BHAVNANI ( Alt"nat, )DR RATTAN LAL Entomology Division. Indian Agricultural Research

Institute ( ICAR ), New DelhiDirectorate General of. Technical Development,

New DelhiIndian Veterinary Research Institute (leAR >,

IzatnacarSHRI S. C. SRIVASTAVA ( Alt,r"a")

( Conli"u,d on /ltJg' 13 )

2

M,mb",SKBI K. VBNXATACHALAII

IS : 1832 • 1978

( Corati,.""d from Pdl' 2 )

R,pr,s,n1inlDepartment of Agriculture, Government or

Andhra Pradesh, HyderabadSRRI K. SATYANARANA RAO ( A.II,mal, )

SHal N. S. \'BNKATARAM.'N Department of Agriculture, Government ofTamil Nadu

DR P. R. VENKATIC8WA1\AN Union Carbide India Limited, New DelhiDR K. N. SHRIVASTAVA ( Al"rnal, )

SSRI N. G. WAOLB Pest Control ( India) Private Limited, BombaySRRI M. R. BAJIKAR ( Alt,rnal, )

DB B. L. WATTA'~ National Institute of Communicable Diseasel, DelhiSURI T. PURNANANDAM, Director General, lSI ( Ex.officio M,mi" )

Deputy Director ( Agri & Food)

S,cr,'arySURI LAJIND1I:R SINGH

Assistant Director (Agri & Food). lSI

Pesticides Subcommittee, AFCDC 6 : 1

C.ft",ranDR K. D. PARABIA Central Insecticides Board, Directorate of Plant

Protection, Quarantine & Storage ( Ministry ofAgriculture & Irrigation), Faridabad

DR N. K. BASU

M,mb,rl

OK N. S. AOARWAL Department of Food (Ministry of Agriculture ItIrrigation ), New Delhi

DB K. KIUSHNAMURTHY ( Alternate)SBKI E. A. ALMEIDA Ciba-Geigy of India Limited, BombayDB H. L. BAKI Central Forensic Science Laboratory, Central Bureau

of Jnvestigation, New DelhiAlkali & Chemical Corporation of India Limited,

CalcuttaDR A. r. D UTTA ( AlI,rMt, )

DB A. K. BHATNAOAl\ Hindustan Insecticides Limited, New DelhiSaar C. C. ABRAHAM ( Alt,r,",', )

DB N. F. DESAI Sandoz ( India) Limited, ThaneOn. p. S. PHADKB ( Alt,rnal, )

DR M. S. DRATT National Malaria Eradication Programme, DelhiSHRI G. I). GOXHALE Bombay Chemicals Private Limited, Bombay

SHRI V. V. KETKAR ( Alt,rnal, )DB K"LYAN SINGH 0. P. Institute of Agricultural Sciences, KanpurSSRI K.. S. MparrA Bharat Pulverising Mills Private Limited, Bombay

SKRI S. CHAftERJI ( AlIer"al, )SRRI L S. MIRL'B Agromore Limited, BangaloreDa S K MUKEKJBE Agricultural Chemicals Division, Indian Agricultural

• • Research Institute ( ICAR ), New DelhiDR N. K. Roy ( Alt,r,"", )

Da S. Y. PANDIT Bayer ( India) Limited, BombaySH.I D. N. NAKHATB ( A.lI,m,," )

( Continrutl 011'dl' 14)

13

IS I 1832· 1978

( Continu,d from /Jag. 13)

~Wtfllb"s Rt/W,smti"gDBT. N. PARTHASARATHY Regional Research Laboratory ( CSIR ), HyderabadPLANT PROTECTION ADVISER TO Directorate of Plant Protection, Quarantine ~

THE GOVBBNJlII:NT 01' INDIA Storage ( Ministry of Agriculture & Irrigation ),Faridabad

Du V. LAX811111NARAYANA ( Alt,mat, )SUBI Y. A. PRADHAN Rallis India Limited, Bombay

SHBI M. L. SHAH ( Alt'"Ii''' )DB V. S. RAMANATHAN Central Revenues Control Laboratory ( Ministry of

Finance), New DelhiSBBI C. DBAJ\JIA RAO Pesticides Testing Laboratory, HyderabadSUKI D. N. V. ItAo Tata Chemicals Limited, Mithapur

SHRI C. NEELKANTBAN ( Alternate)DB K. K. SAXENA Indofil Chemicals Limited, Bomba,

Ssal G. NATABAJAN (Alternat,)SBBI A. C. SHROI'B Excellndultries Limited, Bombay

SHRt P. V. KANGO ( AII,rnat, )SSRI K. SUNDARAM Hindustan Petroleum Corporation Limited, Bombay

SHl\t B. R. AJMAN! ( ...411,'''01' )SBJ&I N. S. VENfCATARAJlAN Pesticides Testing Laboratory, KoviJpattiD. B. L. WA'rI'AL National Institute of Communicable Diseases, Delh j

SDBI V. N. BH4TNAOAR ( AII".1I4t, )

14

IS I 1832 • 1978

Indian StandardSPECIFICATION FOR

MALATHION, TECHNICAL

(First Revision)

o. FOR E W 0 R 0

0.1 This Indian Standard ( First Revision) was adopted by the IndianStandards Institution on 20 March 1978, after the draft finalized by thePest Control Sectional Committee had been approved by the Agriculturaland Food Products Division Council and the Chemical Division Council.

0.2 This standard was first issued in 1961. In this revision an additionalmethod for estimation of malathion content has been given. Otherchanges pertain to the requirements of packaging. marking and sampling,Opportunity has been taken to refer to IS: 6940-1973* to bring unifor­mity in testing procedure for the various requirements given in thestandard.

0.3 Malathion, technical is used in the preparation of formulationsrequired for the control of agricultural and public health pests.

0.4 Malathion is the accepted common name by the InternationalOrganization for Standardization (ISO) for S-l, 2-di ( ethoxycarbonyl)ethyl 0 O-dimethyl phosohorodithioate. The empirical and structuralformulae and the molecular mass of malathion are as indicated below:

Empirical FormulaC1oHl'O.S,P

Structural Formula Moltcul", MIlSS

330-4

.Meth?dl of testl for pesticides and their rormulations.

·18 I 1832 -1978

0.5 In the preparation of this standard, due consideration has been givento the provisions of the Insecticides Act, 1968 and the Rules framedthereunder. However, this standard is subject to the restrictions imposedunder these, wherever applicable.

0·6 For the purpose of deciding whether a particular requirement of thisstandard is complied with, the final value, observed or calculated,expressing the result of a test or analysis, shall be rounded off inaccordance with IS : 2·1960*. The number of significant places retainedin the rounded off value should be the same as that of the specified valuein this standard.

I. SCOPE,1.1 This standard prescribes the requirements and the methods ofsampling and test for malathion, technical, employed in the preparationof insecticidal formulations.

2. REQ,UIREMENTS

2.1 De8criptloa - The material shall be in the form of a colourless toamber liquid free from extraneous impurities, sediments or addedmodifying agents.

2.2 The material shall also comply with the requirements given inTable 1.

S. PACKiNG AND MARKING

3.1 Packi_. - The material shall be packed according to IS : 8190( Part II )-1976t.

3.2 Ma..kID, - The containers shall bear legibly and indelibly thefollowing information in addition to the provisions of the InsecticidesAct and Rules:

a) Name of the material;b) Name of manufacturer;c) Date of manufacture;d) Batch number;e) Net mass of contents;f) Malathion content, percent ( m/m ); and "g) The cautionary notice as worded in the Insecticides Act and

Rules.

• Rules for rounding off numerical values (",iJ,tl ).tRequiremflDtl for packing of pestieldes: Part 11 Liquid pesneide••

4

IS I 1132 • 1978

TABLE I REQ,UIREMENTS FOR MALATHION, TECHNICAL( Claus,s 2.2 arad 5.1 )

SLNo.

CHARACTERISTIO REQUIREMENT ME1':nOD OJ' TEST,REI' TO

r-----..A.--.--.....Appendix of Cl No. ofthis Standard IS: 6940-1973.

(1) (2)

i) Malathion content, percentby mass, Alin

H) Moisture content, percent bymas., Max

iii) Acidity ( as H.SO. ) J percentby mass, Max

iv) Material insoluble in acetone,percent by mall, Ma~

v) Specific gravity at 25/25°C,Mill

(3)

95·0

0·1

0·4

1·23

(4)

A

(5)

4.1

11.'.2

9

5

• Methods of tests for pesticides and their formulations.

3.2.1 The product may also be marked with Standard mark.

3.2.1.1 The use of the Standard Mark is governed by the provisions of theBureau 01 Indian Standards Act, 1986 and tbe Rules and Regulations madethereunder. The details of conditions under which the licence for the use ofStandard Mark may be granted to manufacturers or producers may be obtainedfrom the Bureau of Indian Standards.

4. SAMPLING

4.1 Representative samples of the material shall be drawn as prescribedin the ' Indian Standard Methods for sampling of pesticides and theirformulations' ( under preparation ).

NOTB - Till such time the standard under preparation is published. the mattershall be as agreed to between the concerned parries,

5. TESTS

5.1 Tests shall be carried out as prescribed in col 4 and 5 of Table 1.

5

IS J 1832 - 1978

5.2 Q,aallty 01 Realeat. - Unless specified otherwise, pure che~icalland distilled water ( see IS : 1070-1977* ) shall be employed in test••

NOTE - 'Pure chemicals' shan mean chemicals that do Dot contain impuritielwhich affect the results of analysis.

APPENDIX ArTabl, 1, Item (i) ]

DETERMINAT~ON OF MALATHION CONTENT

A-O. GENERAL

A-G.l For the determination of malathion content, two methods, oneusing the pure Standard malathion (set A-I) and the other usingPotassium salt or 0,0 dimethyl phospborodirhioic acid ( se« A·2) havebeen specified. Either one of the two methods may be used for determi­nation of malathion content. However, in case of dispute, the methodemploying use of pure Standard malathion (see A-I) will be refereemethod.

A-I. PRINCIPLE OF METHOD

A-I.I Malathion, S·l, 2·di (ethoxycarbonyl) ethyl ° O-djmethylphosphorodithioate, is decomposed by alkali in ethyl alcohol tosodium O,O-dimethyl dithiophosphare, sodium fumarate, and ethylalcohol. The sodium O,O-dimethyl dithiophosphate is then convertedto the cupric complex which is soluble in carbon tetrachloride with theformation of an intense yellow colour. The colour intensity is proportionalto the concentration of O,O-dimethyl dithiophosphoric acid and ii measuredcolorimetrically at 420 nm, the absorption peak. The correspondingamount of the insecticide is derived by comparison with a standardprepared with a known amount of the pure insecticide which issimultaneously carried through the procedure.

A-I.I.I In this method, ferric reagent is added to oxidize materialswhich would reduce cupric ions to cuprous ions; with dithiophosphoricacid, cuprous ions form a colourless complex which is apparently more'stable than the yellow cupric complex.

A-I.2 Apparata8

A-l.2.1 Splclrophotom,ter Dr Photoelectric Colo,imeter - with a blue filter( 420 nm ) and having l-cm absorption cells •

•Specification for water for general laboratory usc (s",nd "vision ).

6

IS 11832 -1978

A-I.3 Realeat.

A-I.S.1 Malathion

A-l.3.2 Acetonitrile - boiling range 80 to 82°C.

A-I.3.3 Etn)l Alcohol - anhydrous.

A-I.3.4 Carbon Tetrachloride

A-l.3.5 Sodium Hydroxide Solution - 0-5 N. Dissolve 4-0 g of sodiumhydroxide in 200 rnl of water.

A-I.3.6 Ferric Reagent

A-I.!.6.! Stock solution - Dissolve 4·0 g of ferric chloride( FeCJa6H~O ) and 160 ml of concentrated hydrochloric acid in waterand dilute to 500 ml,

A-I.3.6.2 Dilute solution - Dilute 25 ml of the stock solution withwater to 1 000 ml.

A-l.3.7 Copper Sulphate Solution - 1·5 percent (m/v). Prepare bydissolving 1·5 g of copper sulphate ( CuSOc.5H20) in 100 ml of water.

A-l.4 Preparation or Standard and Sample Solutioa.

A-I.t.O It is very important in preparing the Standard and Samplesolutions that volume fluctuations with changing temperatures areavoided, This is accomplished by bringing each solution to the volumemark just hpf"rp proceeding to the next step in the procedure, asindicated.

A-t.f.t Preparation of Standard Solution

A-t.et.t.l Accurately weigh into a 5-ml or lQ.ml beaker,0-100 ± 0-020 g of pure malathion. Quantitatively transfer it to alOO-rol graduated flask with ethvl alcohol. Then dilute with ethylalcohol to approximately 5 rot below the volume mark. Allow thesolution to come to a selected temperature. Record this temperature,Dilute the solution with ethyl alcohol to the mark and mix well. Callthis as Standard Solution A.

NOTI--: - Standard Solution A may be retained for daily use up to two weeks, It i.very important, however, that it be adjusted to the temperature recorded abovebefore aliquot. are withdrawn.

A-l.4.1.2 Transfer a 15 ml aliquot of Standard Solution A into a250-ml graduated flask. Add 2'5 ml acetonitrile and dilute with ethylalcohol to approximately 5 ml below the volume mark. Retain thesolution until Sample Solution (se' A-l.4.2) is prepared and is ready forfinal dilution. At that time. dilute with ethyl alcohol to the mark andmix well. Call this as Standard Solution.

7

IS I 1832 • 197.

A-I.4.2 Pr,paration of Sampl, Solutions

A-l.4.2.1 Accurately weigh a quantity of the sample containing0·300 ± 0·020 g of malathion and quantitatively transfer to a 50·m]bottle and then add 50 ml of acetonitrile. Close the bottle rightlv witha screw cap having a polyethylene liner and shake it vigorously for 2 to3 minutes either manually or on a reciprocating shaker. 1 hen allowthe solidi to settle for 3 to 5 minutes, if necessary, centrifuge for 2 to3 minutes at 1 500 to 2000 rev/min. Call the supernatant liquid asSampl, Solution A.

A-l.4.2.2 Immediately transfer a 25 ml aliquot of Sampl, Solution Ato a 250-ml graduated flask. Dilute with ethyl alcohol to the mark andmix well. Call this as Sampl, Solution B. Then immediately, transfera 25 ml aliquot of Sampl, Solution B to a 250-ml graduated flask. Dilutewith ethyl alcohol to the mark and mix well. Call this as Sampl, Solution.At this time, also dilute the Standard Solution.

NOTB - ICmore than one sample lolution is being prepared for aual, then allSam", Solutions and the StantltITti Solution should be diluted to approximately 5 mlbelow the volume mark .s prepared. All should be diluted to the volume mark at ttaClame time.

A-I.5 Procedure

A-I.5.0 1"'0 obtain accurate re-sults, it is important that the analysis orStandard and Sample Solutions be carried simultaneously through theprocedure given in A-I.5.l to A-I.5.4 without interruption.

A-I.5.1 Transfer a 25 ml aliquot of Standard Solution and one Sampl,Solution to two different 25O-ml separating funnels. Add 2 ml of sodiumhydroxide solution and mix well by swirling gently (do not shake)for 5 to 10 seconds. Allow the solution to stand for exactly 2 minutes.

A-I.5.2 Immediately add 75 ml of ferric reagent and mix well byswirling for 10 seconds. Allow the solution to stand for exactly5 minutes. During this 5 minutes period, fill two SO-rot graduatedflasks to the mark with carbon tetrachloride and after the lapseof 5 minutes simultaneously transfer the carbon tetrachloride from eachgraduated flask to the respective separating funnels. AJlow the flask todrain for one minute.

NOTB - From this point onward the Sam," Solution and Standard Sol"tion should behandled separately. Carry each one through the next step 'Yithout interruption.

A-1.5.3 Add 2 ml of copper reagent. Start shaking the separatingfunnel immediately after addition of copper reagent for exactly oneminute. The malathion-copper complex is unstable in the aqueousphase. The copper reagent should be added with a fast delivery pipetteand the shaking should be started with practically no time lapse. Allow

8

IS I 1832 - 1"8

the phases to separate. As soon as separation occurs, discard theaqueous phase. Allow some solvent phase to rinse the stem of theseparating funnel, then run the clear solvent phase into a small beakerfor transferring to an absorption cell or run the clear solvent phasedirectly into the cell.

A-l.5.4 Measure the absorbance of the yellow solution within5 minutes at 420 nm using carbon tetrachloride as the blank.

NOTE - Absorbance measurements of both Standardand Sampl, Solutions should bemade at the same fixed time after the end of the shaking period. The yellow colouroftht' copper complex in carbon tetrachloride is unstable, hence the colour should beread within 5 minutes aftt'r extraction. During this time the absorbance readingdrops very slowly,

A-I.i CalculatioDA-I.6.1 'The absorbance measurements of the Standard and Sample

Solutions should agree within ± 10 percent of each other.

A-l.6.2 Malathion content, percent by mass ... -~ X ;; x f X 3'0

whereA == absorbance of Sample Solution at 420 om,m = mass in g of pure malathion taken for the preparation

of StandardSolution,f = percentaze purity of the malathion used for the prepara­

tion of Standard Solation.B == absorbance of StandardSolution at 420 nm, and

M == mass in ~ of the material taken for the preparation ofthe Sample Solution.

A-2. PRINCIPLE OF METHOD

'\-2.1 The sample is hydrolysed quantitatively with ethanolic alkali in ananhydrous medium to give the sodium salt of O,O-dimethyl phosphore­dithioic acid. The salt is then dissolved in ethyl acetate in which theexcess alkali is insoluble. An aliquot is diluted with cyclohexane andcopper naphthenate is added. The copper (II) ion reacts with theO,O·dimethyl phosphorodithioate ion to form a yellow-coloured complex.The intensity of the colour is proportional to the concentration ofO,O-dimethyl phosphorodithioate ion present and is measured colorl­metrically at 420 nm. The amount of diethyl mercaptosucinate S-esterwith O,O-dimethyl phosphorodithioate is then determined by comparingthe observed absorbance measurements with a calibration graph relatingabsorbance to various concentration of primary standard potassium saltof O,O·dimethyl phosphorodithioic acid complexed with copper (II)ion in a similar manner. Water and free mineral acids are excludedfrom the reagents to prevent decomposition of the copper complex.

9

IS : 1832 - 1978

A-2.2 Apparatus

A-2.2.1 Spectrophotometer or Photoelectric Colorimeter - with blue filter(420 nm) .

.4.-2.3 ReageDts

A-2.3.1 Potassium Salt of O,O-Dimethyl Phosphorodithioic Acid - Preparethe pure salt according to directions given in Appendix B.

A-2.3.2 CJclohexane - 98 percent passed through a column of activatedsilica gel to remove polar materials.

A-2.3.3 Ethyl Acetate

A-2.3.4 Alcoholic Sodium J-/yJroxide Solution - O· 1 N in ethanol.Prepare by dissolving 4 g of carbonate free NaOH in 100 ml of absolutealcohol.

1..-23.5 Copper Reagent - Dissolve 420 ± 10 mg of copper (II)naphthenate in 100 ml of cyclohexane.

,\-2.3.6 Aceton«

A-2.4 Procedure

A-2.4.1 Preparation of the Standard Curve

A-2.4.1.1 Weigh accurately 0·08-0·1:! g of pure potassium salt ofoO-dimethyl phosphorodithioic acid into a 50-ml volumetric flask,dilute to volume with acetone and mix.

A-2.4.1.2 Pipette 5 ml of this solution into a 50..ml volumetric flask,add 2 ml of sodium hydroxide solution, make up to the mark with ethylacetate, mix and allow to stand for 10 minutes.

A-2.4.1.3 Transfer portions to the 15-ml stoppered centrifuge tubesand centrifuge for 5 minutes. Pipette 3, 4, 5 and 6 ml of the centrifugedethyl acetate solution in to separa te 50-ml volumetric flasks taking carenot to transfer any of the precipitated sodium acetate. Add approxi­mately 35 ml of cyclohexane followed immediately by 2 ml of copperreagent. Mix and make each up to the mark with cyclohexane.

A-2.4.1.4 Measure the absorbance of each solution at the wave­length maximum near 420 om within 2 minutes after adding the copperreagent) using a reference solution carried through the same steps butcontaining no standard salt.

A-2.f.I.5 Prepare a calibration graph by plotting the absorbaneesobserved for the four solutions against their O,O-dimethyl phosphorodi­thioic acid, potassium salt content in micrograms per ml,

10

IS I 1832 - 1978

A-2.4.2 Prtparation of the Sample

A-2.4.2.1 Weigh accurately a sample containing 0-15 ± 0'05 g ofmalathion into a 50-rol volumetric flask, dissolve, and make up to themark with cyclohexane.

A-2.4.2.2 Pipette a 5 ml aliquot into another 50-m) volumetric flask,add 2 ml of sodium hydroxide solution, mix, and allow to stand for10 minutes. Make up to the mark with ethyl acetate, mix, and allowto stand for 10 minutes. Transfer approximately 10 ml of the solutionto a 15-ml stoppered centrifuge tube and centrifuge for 5 minutes.

A-2.4.3 Analysis of tilt Ala/trial

A-2.4.3.1 Pipette 5 ml of the centrifuged ethyl acetate solution ofthe sample into a 50-lnl volurnerric flask taking care not to transfer anyof the precipitated sodium acetate. Add approxirnately 3~ 'ml of cycle­hexane followed immediately hv 2 ml of copper reagent. Mix and makeup to the mar k with cyclohexane,

A-2.4.3.2 Measure the absorbance at a wavelength maximum near420 nrn 2 minutes after adding the copper reagent, using a referencesolution carried through the same steps but containing no malathion.

A-2.4.3.3 Refer to the calibration graph and determine the equivalentconcentration of O,O-dimethyl phosphorodithioic acid, potassium saltin the solution in micrograms pt'r ml,

A-2.5 CalcuJation

a X 1·683Malathion content, percent by mass = "' X 2

where

a = equivalent concentration (p.g/ml) of OJO-dimethyl phos­phorodithioic acid, potassium salt in the unknown solution,determined from the calibration graph; and

m 2:::: mass in g of the sample taken.

NOTB - Since volume changes of nonaqueous solutions with temperatureare appreciable, the analysis of !he sample, Iho~.a1d be carried out. as rat aspossible, at th~ temperature at which the calibration graph was prepared,

11

IS I 1832 • 1978

APPENDIX B( Claus, A-2.3.1 )

PREPARATION OP THE POTASSIUM SALT OFO,O-DIMETHYL PHOSPHORODITHIOIC ACID

B-1. REAGENTS

8-1.1 Phosphora. Peat.sulphlde - A.R.

8-1.2 Diethyl Ether

8-1.3 Metbaaol

8-1.4 Ethaaol - anhydrous.

8-1.5 BeDzeDe - free of thiophene.

8-1.6 Metha.olic Pot•••iam H)'droside - 3 N. Dissolve 168 g ofKOH in 1 litre of methanol.

B-2. PROCEDURE

8-2.1 Make a suspension of 222 g of phosphorus pen tasulphide in 100 mlof benzene and add, under cooling, J28 g of methanol. After thereaction has finished, neutralize to pH not below 4, with 600-700 mlof 3 N metbanolic potassium hydroxide, using a pH meter and coolingin ice so that the temperature does not exceed 20°C_

8-2.2 Filter the reaction mixture and add 1000 ml of diethyl ether toprecipitate the potassium salt. Filter off the precipitate, wash withdiethyl ether, and dry, Recrystallize once from methanol and twicefrom ethanol, preparing saturated solutions by short boiling andprecipitating by cooling to O°C. Finally, dry the salt in a vacuumdesiccator.

B-3. DETERMINATION OF PURITY

B-3.1 Dissolve 0-300 g of the salt in 25 ml of glacial acetic acid andtitrate with 0·1 N perchloric acid; 1-00 rnl of 0-1 N perchloric acid isequivalent to 0'019 3 g of the pure potassium salt.

8-3.2 Calculate the percentage purity. The purity obtained by thismethod is greater than 99 percent.

12

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