PESTICIDES J . L. S T . JOHN Stale College of Washington, Pullman, Wash.
I
NTEREST in pesticides and in spraj residue has continued a t a high level for several years. One manifestation of this is the formation in 1949 of the Pesticide Subdivision within the Division CHEJ~ICAL of Agricultural and Food Chemistry of the AMERICAN SOCIETY. Another evidence was the formation of the Association of Economic Poisons Control Officials during the years 1946-1947. This includes regulatory workers and experiment station men from both state and federal governments. Much emphasis has been placed on the need for safety during application of pesticides, and safety of foods which may in some cases unavoidably retain minute residues of pesticides. The use of these chemicals to control pests is generally conceded to be imperative. Some of the newer organic pesticides are highly toxic to man and animals, although they do not have a higher toxicity than some of the older pesticides such as arsenic, and particularly nicotine, which is said by Lehman (81) to be one of the most highly toxic materials known. A clear distinction should be made b e h e e n hazards during use, and food hazards. A vast amount of work has been done by state and federal experiment stations and regulatory agencies, and by industry and private laboratories to reduce any danger to public health to an irreducible minimum. .4n important link in the safety chain is the development of specific and precise analytical methods, both macro and micro, which are adaptable t o determine the quantity of pesticides both in formulations and in foods. Development of such analytical methods has been in active progress during the past three years and is continuing. The determination of the toxicity of these newer pesticides, which is essential as one factor in the evaluation of safety in their use and consuniption, is also receiving much research attention, as is research on effectiveness and other phases of this complex pesticide problem. Official methods have already been developed ( 2 ) for a material number of pesticides, by the association of official agricultural chemists. Many unpublished macromethods are available through the Methods Clearing House of the Association of Economic Poisons Control Officials. Micromethods for spray residue analysis were presented during hearings on spray residue and are available for inspection a t the offices of the Food and Drug Administration. T h a t administration also (SO) refers to newly developed methods for benzene hexachloride, mercury and 1080 (sodium fluoroacetate). Many micromethods were presented in the Symposium on Analysis of Micro Quantities of Pesticides CHEXICALSOCIETYin a t the Boston meeting of the AMERICAN April 1951. RIethods presented a t the San Francisco and Atlantic City meetings of the Society appear in Advances in Chenaistry Series, No. 1. Methods more recently presented in Society symposia will appear shortly in Advances in Chemistry Series, No. 8. Research papers on analytical macro and micro proceduree, including microbioassay methods, published during 1950, 1951, and up to October 1952, are briefly reviewed below. METHODS PRIOR TO 1950
-4number of papers review analytical methods for pesticides published prior to 1950. Haller ( 5 3 , 6 4 )summarized these methods in San Francisco a t the Symposium on Economic Poisons. His paper reviewed methods for chlorinated hydrocarbons, phosphorus compounds, and piperonyl derivatives, including colorimetric and physiochemical methods. Methods for determining composition and purity of commercial grades of pesticides 42
were available, but there weie comparatively few procedures for the analysis of formulations, particularly in the presence of interfering substances Some micromethods were available. Wichmann (128) reviewed the available methods for the microdetermination of spray residue of several metallic elements, DDT, and 1080 in foods. Methods for organic pesticides such as benzene hexachloride and parathion, and for loss of organic insecticides in the canning process, x r e briefly summarized, Specific recommendations were made on analytical methods needed. Bottini and Fantini ( 6 )reviewed methods for the determination of the gamma isomer of benzene heuachloride. Buhrer (11) reviewed the methods for the determination of benzene hexachloride in dusts and other technical products. Ginsburg ( 4 1 ) reviewed and commented on eight chemical methods of different types for the determination of DDT. Krauze and Rzymowska ( 7 7 ) presented a complete review and critical discussion of methods of estimating DDT, particularly for food products. Jakobs and Hong ( 7 0 ) compared different methods for D D T and selected that of Schechter, Solway, Hayes, and Haller as the most accurate. Meyer (88) compared D D T methods for technical mixtures and selected the Schechter-Haller method as best, but recommended the isolation of D D T by chromatographic means. Wasicky (126) reviewed niethods for modern insecticides, including 117 references. Graham (42-44) reported on critical studies of pesticide methods and made recomniendations regarding further study of methods for benzene hexachlaide, rotenone, chlordan, piperonyl butoxide, warfarin [3-(or-acetonylbenzyl)-4-hydroxycoumarin], potassium cyanidr, herbicides, 2,4-D, 2,4,5-T, allethrin, quaternaries, parathion, antu [ 1-(l-naphthyl)-2-thiourea],tetraethyl pyrophosphate, fluorine, arsenic, pythrins I and 11, limesulfur, carbamates, organic thiocyanates, and others. BIOASSAY METHODS
An interesting approach to the measurement of the relative quantity of residue in foods has been the development and adaptation of bioassay methods for the &mation of micro quantities. Hartzell (58) presented data on the toxicity of spray residue of fresh and processed fruits and vegetables a t the San Franscisco (1949) meeting of the Pesticide Subdivision of the AMERICAN CHEMIcAI, SocImY. The bioassay procedure was adapted from the method of Kolan and Wilcoxon (91) for the determination of insecticide residues in fresh and processed fruits and vegetables. The method utilized the fact that benzene extracts of foods are toxic t o certain mosquito larvae. It was found suitable for concentrations of parathion as IOTV as 0.02 p.p.m. The average LDm of parathion, benzene hexachloride, DDT, and toxaphene using the larvae of Aedes a e g y p t i came n-ithin the range of 0.003 to 0.1 p.p.m. Hartzell and Storrs (59) presented further data on about 15 of the newer organic pesticides in processed foods. Various insecticides were readily detected when added to processed foods a t concentrations of 0.5 to 5.0 p.p.m. Hoskins and Messenger ( 6 8 ) presented a bioassay micro niethod for insecticide residues in plant and animal tissues. A chloroform extract of D D T or benzene hexachloride was m s h e d with concentrated sulfuric and an extract of parathion was purified by passage through an absorption column. After evaporation, the common housefly was exposed in an especially designed vial. The LDSO for parathion, benzene hexachloride, and D D T was about 0.56 to 6.7 microgranis per vial. Frawley, Laug,
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V O L U M E 25, NO. 1, J A N U A R Y 1 9 5 3 and Fit'zhugh (34) described a procedure for the bioassul- of insecticides by oral administration t,o flies. An ether extract of a food sample is evaporated to dryness over sugar and a water solution is then fed t o flies previously fasted for 24 hours. The method is sensitive in the range of 3 to 15 micrograms of parathion, lindane, E P N (ethyl-p-nitrophenyl thionobenzenephosphorete), and DDT. The same authors (56) utilized the parathion of cholinesterase as the basis for estimation of micro quantities of organic phosphate insecticides. Flies fed the water solution are blended with a Waring Blendor and the cholinesterase activity of an extract is measured. This method is sensitive in the range of 0.5 t o 2.0 micrograms of parathion and EPS. Fleming, Coles, and hIairies (32) studied a bioassal- method for r e d u e s of D D T and chlordan in soil. Bushland (13, attempted to utilize mosquito larvae in a bioassay method for determining insecticide residues i n animal products. D D T , T D E [l,l-dichloro-2,2-bis(p-chlorophenyl)ethane~,methosychlor, lindane, chlordan, and toxaphene were determined in meat, milk, and butter. Sun and Sun (120, 121) critically evaluated essential factors in bioassaj- methods. They discussed the principles, precautions in sampling, procedures, and several types of microbiologic>almethods. They also considered sensitivity and interferences. The!- pointed out that some chemical methods as well as bioasha!. methods lack speciticity, and presented the advantages of iuicrohioassay methods for certain types of problems. RESIDUES I 3 FOODS
The isolation of organic insecticides from plant and animal tissues is one of the most difficult analytical problems. An interesting contribution to this problem was made by Jones and Riddick ( 7 2 ) utilizing an organic solvent and a differential solubility method with immiscible solvents. Such a method should find application ivith dilan, methoxychlor, parathion, chlordan, lindane, and D D T . n-Hexane and acetonitrile were used. These pesticides hnve been separated in milligram and and microgram quantities. The authors obtained a recovery in general of 90 t o loo%, with accurscy within 5To0 T h e method is rapid and convenient, and should be adaptable t o recover)of a large variety of organic compounds from plant and animal tissues. There has been much discussion but few data regarding the consumption of pesticide residues by the public. The available data were coordinated and summarized by St. John (lid), who emphasized the need for many added data to demonstrate the true situation. No known cases of difficulty from consumption of permitted quantities of residue in foods appear to be recorded. Utilizing methods such as those of Jones and Riddick (72j, Hartzell (58), Hoskins and hlessenger (68), Frawley et al. (341, and Sun (120) it should be possible to obtain adequate data on the quantity generally consumed, in order t o demonstrate B health hazard if any exists.
corn. T h e Schechter-Haller procedure was found accurate and precise but not well adapted t o routine analysis. The Stiff-Castillo method was found to be the most rapid and nearly equal in precision and accuracy to the Schechter-Haller procedure. The organic chlorine method is adaptable to routine analysis but is less accurate, less precise, and not as specific as the other tvvo methods. The authors described a modification of the Stiff-Castillo colorimetric procedure. Ginsburg ( 4 1 ) compared eight methods for D D T . Guha ( 4 6 ) described a modification t,o adapt the British Pharmacopoeia method to climatic conditions in India. Gunther and ;LIiller (60) devised equipment to increase the efficiency of anslysis. Jakobs and Hong ( 7 0 ) compared methods and found that of Schechter, Solomy, Haynes, and Haller the most accurate. hlann and Carter (85) improved the procedure for extraction of D D T from milk. hleyer (88) compared methods on technical D D T mixtures. For traces of D D T in foods they found the Schechter-Hsller colorimetric method best, but D D T should first be isolated by chromatographical means. Xorton and Schmalzriedt (92) proposed a method by percolation through alumina to remove interfering extractives in the colorimet'ric method of SchechterHaller. Prickett, Kunze, and Laug (101,10R) presented a rapid method for determination of D D T and methoxychlor in animal tissues and modified the Schechter method for D D T in biological materials by saponification and petroleum ether extraction. This does not differentiate between methoxychlor and the isomers of D D T . Fleck (31j reported on collaborative studies. Schechter ( 1 1 4 ) stated a correction or modification of previous methods. Davidow ( 2 1 ) presented what is judged to be a good method for the isolation of D D T from fats by use of a chromatographic column using carbon tetrachloride. Tamamushi and Tanaka (122) presented a polarographic method for the determination of lindane and D D T in their mixtures. The isomers of D D T are not distinguished. Pag&n and Hageman (95, 96) described a method for the determination of D D T by bioassay, using fish to determine D D T residues on vegetables. I t was not applicable to milk. hLIellini (87) described a new method for D D T based on refluxing the sample with alcoholic potassium hydroxide and titration of the excess. Harris (55) has applied partition chromatography in the analysis of insecticide formulations. He described a procedure for the determination of benzene hexachloride and D D T in formulations also containing sulfur. The procedure has also been applied t o the analysis of technical methoxychlor. Results reported indicate that partition chromatography may find other applications in the analysis of insecticide formulations. -4 certain degree of specificity appears to be characteristic. Carter, Selson, and Gersdorff ( 1 4 ) showed a general agreement between the insecticidal level calculated from organic chlorine determinations and the data obtained by fly mortality procedures. Such agreement was found for toxaphene, benzene hexachloride, and D D T on alfalfa and in animal fat.
DDT
BENZENE HEX4CHLORIDE
The literature for 1950, 1951, arid 1952 carries more papers on analytical methods for D D T than for any other pesticide. A number of these are revievs or a comparison of two or more methods. Krauze and Rzymowka ( 7 7 ) reported a comprehensive and critical discussion based on experience with D D T methods, especially in foods Carter (13) reported the collaborative study of D D T bj- two methods which proved about equally accurate but of questionable accuracy for small quantities of D D T . Davidova ( 2 0 ) reported a procedure for a determination of D D T in commercial preparations in the presence of pyrethrin and coloring matter. Downing and Norton ( 2 3 ) studied a modification of the Schechter method to increase the speed of determining D D T residues. Fahey and Rusk (29) compared three methods for residues on
Considerable attention has tieen given t o methods for benzene hexachloride. Bowen ( 7 ) ieviewed methods available preceding 1950. He brieflj- discussed methods for total and hydrolyzable chlorine, turbidimetric methods, and ultraviolet adsorption of the dehydrochlorinated product. He also reviewed methods for determining the gamma isomer, including fractional eytraction and selective precipitation, use of an infrared spectrometer which mas the first practical method employed, and chromatographic, cryoscopic, polarographic, mass-isotope dilution, and chemical methods. Bowen reported a comparison of the partition chromatographic method and the infrared spectrometer method and recommended that these be adopted asofficial alternative methods for the determination of the gamma isomer in technical benzene hexachloride. Both methods give consistent re-
ANALYTICAL CHEMISTRY
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sults with known synthetic mistures and unknown samples. He also recommended t'hat' the chromatographic method be adopted as official for the gamma isomer in wettable powder and dust formulations. Buhrer ( 11 ) reviewed methods for benzene hesachloride in dusts. Bottini and Fantini (6) revien-ed niethods and presented a method for the determination of the gamma isomer by fractional solution. Arceneaus ( 1 ) described a microscopic method for t,he qualitative and quantitative determination of the gamma isomer of benzene hesachloride. After crystallization, depression of melting point times a factor gives purity m-ith a precision within 1% in a 90 to 100yo gamma isomer product. The method may be applicable to other isomers and other organic crystalline material. Granger and Zwilling ( 4 6 ) described a chromatographic method. Harris (65) presented a chromatographic method for the determination of lindane in formulations, which gives results vithin 2% but is time-consuming. This method may be applicable to other pesticides. Hasselbach and Schwabe (60),Monnier, Roesgen, and Monnier (go), and Tamamushi and Tanaka (122) described polarographic methods for benzene hesachloride. Luther, Lampke, Goubeau, and Rodewild ( 8 4 ) gave a method for the detection and determination of isomers of benzene hexachloride by means of a Raman spectrograph. Schechter and Hornstein (116) presented a colorimetric method and Toops and Riddick (124) a cryoscopic method for benzene hesachloride and lindane. Fossum and Riddick (33) described a met,hod designed originally for drugs. Dalma and Garzon ( 1 7 ) and Roth (111 ) presented gravimetric methods for determining the gamma isomer. Hoskins and Messenger ( 6 8 ) described a microbioassay method for insecticide residues in plant and animal tissues, using flies, and applicable t o several pesticides. Tuft's, Darling, and Kimball (126) discussed the application of the Davidow and JVoodard method for the determination of the gamma isomer in milk and beef fat. It appears satisfactory for animal tissue but not specific. Hoskins, Wtt, and Erwin ( 6 9 ) discussed and improved a bioassay method for lindane and considered procedures for standardizing the processes. ORGANIC PHOSPHORUS COMPOUNDS
I n 1948 ilverell and Korris ( 3 ) published a colorimetric method for the microdetermination of parat'hion. Bowen and Edwards ( 8 , 9 ) developed a polarographic method for parathion, in w-hich an accuracy within 1% is obtained. The colorimetric procedure of Averell and Yorris is not suitable for application to the analyses of technical materials. O'Keeffe and Averell ( 9 4 ) described a method in which parathion is titrated with sodium nitrite in an ether solution. The method is not specific, but there is no evidence that the interfering compounds would be present in significant amounts in parathion. T h e method is applicable to technical parathion and dust formulations. Gage ( 3 7 )modified this method. I n 1950 Edwards (26-27) summarized colorimetric, polarographic, ultraviolet, and distillation and titration methods for the determination of parathion and their application to the analysis of formulations. He emphasized that Averell and Xorris had stated that the colorimetric method was not applicable to dusts and wett'able powders. I n 1952 he reported on a comparison of the polarographic and sodium nitrite methods. He recommended that the nitrite method be adopted as official for technical parathion and dust formulations. Simmons and Robertson (118) presented an osidation method for determination of organic phosphates, with completion by titration. Precision was within a few tenths of 1%. Ketelaar and Hellingnian ( 7 5 ) described a method for parathion in technical preparations and formulations, based on saponification followed by colorimetric determination. The accuracy on synthetic mixtures is within 0.3%. Kolan and \I-ilcoxon ( 9 1 ) presented a bioassaj- method for parathion in plant material.
They macerated in Fater tvith a Waring Blendor, extracted with benzene, and esposed the larvae of Aedes aegypti for 40 hours. The LD60was determined by comparison n-ith a standard mortality curve; 0.02 p.p.m. of parathion may be measured. Gunther and Blinn ( 4 8 ) outli'ned an adaptation of the Averell and Norris (3) method for the qualitative detection of parathion in orange and lemon oils. Hirt and Gisclard (66) described a method for the determination of parathion in air samples by ultraviolet spectroscopj-. This is designed for control during manufacturing and packing operations. It may also be adapted to the determination of parathion in wettable powders or dusts. Blinn and Gunther (5) discussed a method for the prevention of interference by methyl ant,hranilate. Ripper, Greenslade, and Hartley (107') described a test for the presence of the systemic insecticide, octamethyl pyrophosphoramide, and Hall, Stohlman, and Schechter (52) described a colorimetric determination of this compound. They used chloroform estraction and acid hydrolysis, and completed the procedure with a photoelectric colorimeter. Giang and Hall (40) published an enzymatic method for the determination of organic phosphorus utilizing cholinesterase. Parathion is first converted to paraoxon (diethyl p-nitrophenj-1 ester of phosphoric acid), which is a strong inhibitor. They detected parathion to hundredths of a microgram. The method is not specific, but may be utilized with a number of phosphorus insecticides. It is thus applicable to Systox. Hall (61)reported on TEPP and recommended that the method of Wreath and Zickefoose be adopted for technical grades and formulations of TEPP. Gunther and Blinn ( 4 7 ) described procedures to adapt the Averell and Norris (3)method to the mass est'imation of parathion residues on certain fruits and vegetables and miscellaneous substrates. ALDRIN AND DIELDRIN
Danish and Lidov (18, 19) designed a colorimetric method for the estimation of small amounts of aldrin utilizing a spectrophotometer; 10 t o 40 micrograms are readily determined. Commonly used insecticides such as chlordan, DDT, methosychlor, benzene hexachloride, toxaphene, and dieldrin do not interfere. The method is believed adaptable to dusts or n-ettable powders. Garhart, Witmer, and Tajima ( 3 9 )described an infrared method for the microdetermination of aldrin and dieldrin, which has a sensitivity of 0.0005 and 0.0007% for aldrin and dieldrin, respectively, with a probable error of 0.001%. The absorption peak is 8.48 and for dieldrin is 10.98 microns. Sun and Sun (120, 121) critically studied bioassay methods for the microdetermination of pesticides, particularly aldrin and dieldrin. They utilized the same revised procedure in determining T E P P , parathion, and aldrin. A bulletin (117 ) critically review methods for the determination of aldrin. I t considers bioassay, total chlorine, colorimetric, infrared, ultraviolet, and polarographic methods and concludes that the most sensitive and specific method for aldrin is the infrared method, but that suitable apparatus is not available a t present for the satisfactory utilization of this method. The colorimetric, ultraviolet, and polarographic methods are not believed to have real utility for the determination of trace amounts of aldrin. I\-hile not specific for aldrin, the bioassay and the total chlorine methods appear t o be the most generally applicable of those considered. CHLORDAN, TOXAPHENE, HEPTACHLOR, AND METHOXYCHLOR
Davidow ( 2 2 ) proposed a spectrophotometric for the quantitative estimation of technical chlordan. He gave structural formulas for some of the constituents of chlordan. Romano (108) described a titration method for chlordan. Harris (56, 6 7 ) discussed the Davidow and a proposed Hzrris method, m d reported on a study of these methods. h method for technical
V O L U M E 25, NO. 1, J A N U A R Y 1 9 5 3 chlordan and formulations is available from one of the manufacturers. Methods for methoxychlor ( 2 4 ) are summarized by one of the manufacturers. One of these methods was introduced into the Food and Drug Administration spray residue hearingi. Harris (56, 57) reported on toxaphene and concluded that no specific method is yet available for its determination. Kenyon (74) reported an infrared method for its quantitative estimation. Polen and Silverman (100) described a photometric method for the microdetermination of heptachlor, which can be determined a t 3- to 5-microgram levels with a relative precision of 1.5 to 2.0%. Other common insecticides except technical chlordan do not interfere. The method is applicable to residues on foods and detects residues a t a level of 0.01 p.p.ni. ROTENONE
Hornstein ( 6 6 ) outlined a method for the determination of rotenone bj- the use of mercuric acetate, which appears as accurate as the gravimetric method. The liberated acetic acid is titrated with sodium hydroxide. Hornstein (67) also published a method for the determination of rotenone as an impurity. L-p to 10% may be found in dihydrorotenone. The end point is measured with a photometer. Rotenone results are accurate to 0.5%. Payfer ( 9 9 ) reported on rotenone methods. Cupples ( 1 6 ) described an infrared method of determining rotenone in materials using a carbon disulfide solution in a single-beam infrared spectrophotometer. The accuracy is 2%. CARBAMATES
Patterson ( 9 7 ) explored methods for the determination of dithiocarbamates and selected the carbon disulfide method for continued study, measuring end points colorimetrically or iodometrically. Lowen ( 8 6 ) presented a micromethod for the determination of food residues by an electrophotometric determination of carbon disulfide. Clarke, Baum, Stanley, and Hester (16) utilized a n iodine titration and adapted this to both macro and semimicrodeterminations of dithiocarbamates. The procedure was also adapted t o the microdetermination of residues on fruits and vegetables by a modification of the methods of absorbing arid measuring the carbon disulfide. T h e end point x a s determined spectrophotometrically. The methods are those suitable for the determination of dithiocarbamates, for the analysis of dust or spray formulation, and for the determination of spray residues. Patterson ( 9 8 ) studied the latter method and found that collaborators secured a fairly high recovery on commercial samples of carbamates. This study is being continued. HERBICIDES
Isopropyl A'-phenyIcarbamate ( I P C j has been used for selective weed control. Gard (38) developed an analytical method by measuring the carbon dioxide liberated on acid hydrolysis. Results show an accuracy of 99% and a precision within 0.2%. The method offers an advantage over nitrogen determinations, as a smaller factor is required. The carbon dioxide is determined by titration. The chief impurity encountered is diethyl urea. The method may also be applied t o commercial mixtures such as wettable poivders and to carbamate esters. Bissinger and Fredenburg ( 4 ) presented a method for the determination of micro quantities of I P C which detected the residue in quantities as low as 0.16 p.p.m. The sample !\-as macerated in a Waring Hlendor and after extraction, separation, and hydrolysis, the final ineasurement was made colorimetrically. Interfering substances n w e not eiicountered. Heagy (61-5'3) reported on collaborative studies of macromethods for 2,4-D and recommended certain changes in previous procedure and continued study. He also reported on a procedure for potassium cyanate. Fromm (36) reported a biological method for the quantitative evaluation of herbicides by action
45 on duckweed (Lernna minor). His procedure utilized sodium chlorate, ammonium thiocyanate, ammonium sulfamate, and 2,4-D. A "phytocidal index" was proposed. Marquardt and Luce ( 8 6 )developed a colorimetric method for the determination of small amounts of 2,4-D in milk, using a spectrophotometer. Concentrations of less than 0.2 p.p.m. can be determined. KOinterferences were encountered. Lowen and Baker ( 8 3 ) present methods for the macro and micro colorimetric determination of CMU weed killer. Quantities as lon- as 0.05 p.p.m. of residual 3-(p-chlorophenyl )-1,l-dimethylurea, its active ingredient, have been determined in soils. ORGARIC THIOCYANATES
Rooney (109, 110) collaboratively studied an earlier procedure for organic thiocyanate and recommended revisions in the procedure for use on livestock and in fly spray. PYRETHRINS
Kelsey (73) modified the official SOSC method to improve the yield and reduce the time required for analysis. Edwards and Cueto ( 2 8 )developed a procedure for the colorimetric estimation of pyrethrins on coated paper bags utilized for control in manufacture and for determining the stability of pyrethrins during storage. Schreiber and NcClellan (116)developed a method to reduce the interference of fatty acids for the determination of insecticide residues found in flour from pyrethrin-treated bags. 1080, ANTU, AIYD WARFARIN
Ramsey and Clifford (103, 105) presented a method for the determination of monofluoroacetic acid in foods and biological materials. The prepared sample is ether-extracted and alkaliwashed, and the 1080 is separated by chromatography and converted t o inorganic fluoride, which is determined by established technique. A critical step is the chromatographic separation of monofluoroacetic acid from inorganic fluorine acids. The method is highly specific in the presence of inorganic fluorine and gives quantitative results with concentrations as low as 0.2 p.p.m. Ramsey (104)developed a chromatographic method for the separation of monofluoroacetic from other acetic acids. Ramsey and Patterson (106) designed a qualitative test t o confirm the presence of 1080, based on the formation of thioindigo, for use in conjunction with the Ramsey and Clifford (105) quantitative method. This test is suitable for foods and biological materials containing 1080 a t a level as low as 1 p.p.m. LaClair (78, 7 9 ) studied and slightly revised the AOXC method for the determination of antu. LaClair ( 8 0 ) presented modifications of the JVisconsin Research Foundation procedure for warfarin. The three procedures are based on ether or ethylene dichloride extraction and final measurement with spectrophotometer. Satisfactory results are obtained n-ith levels of 0.025yo rarfarin. PIPEROYYL BUTOXIDE
Jones, dckermann, and Kebster ( 7 1 ) developed a colorimetric method for the determination of piperonyl butoxide. The color reaction appears to be specific. .A spectrophotometer may be used at a wave length of about 630 m l . The method has been applied successfully t o oil solutions containing pyrethrins as well as t o dusts, paper coatings, and other materials. I t s precision is within about 370 a t a level of 5 to 75 micrograms of piperonyl butovide per 0.1-ml. aliquot. Samuel (113) studied the above and the Harris methods. ARAMITE AND GLYOXALIDINE
Gunther, Blinn, Kolbezen, and Barkley ( 4 9 )designed a method for the determination of aramite residues, based on the quantitative liberation of ethylene oxide and the spectrophotometric
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ANALYTICAL CHEMISTRY
determination of the color produced with lepidine. Transmittance is measured at 610 mp. Results are obtained in the range to 10 to 500 micrograms and spray residue is determined a t levels of less than 1 p.p.m. Hillenbrand, Sutherland, and Hogsett ( 6 4 ) developed a method for the determination of glyoxalidine residues, which involves a titration of the glyoxalidine and the hydrolysis products. It is accurate and reproducible to 2 p.p.m., and has been used in the range of 10 to 20 p.p.ni. QUATERNARY AMMONIUM COMPOUNDS
Tillson, Eisenberg, and Wilson (133) prepared the Reineckate salts of two ammonium compounds and determined the optical crystallographic properties which may be employed in the identification of the salts. Wilson (129) published a method for the quantitative determination of two ammonium compounds by preparation of the Reineckate salts. Recoveries at the 50- and 100-mg. levels were good, with a maximum range from about 91 t o 107%. Recovery at the 10-mg. level was good for many of the salts, but in some cases ranged down to around 70 or 80%. COPPER, MERCURY, AND ARSENIC
Stammer (119) discussed the status of micromethods for the determination of copper in foods. hliller, Polley, and Gould (89) adapted the diphenylthiocarbazone method to the microdetermination of mercury compounds for utilization in determining the stability of some fungicides in the presence of soil and plant material. The end point was determined with the photoelectric colorimeter. One to 150 micrograms may be determined in presence of many metal ions. including inorganic mercury. The accuracy is within approyimately 2%. Odencrantz and Rieman (93) proposed a method for total arsenic which involves the oxidation of arsenic to the quinquevalent state, separation from interfering ions by use of hydrogen ion exchange column, and titration of the arsenic with thiosulfate. This method eliminates the lengthy AOAC distillation. Kingsley and Schaffert (76) believe that the most satisfactory method for the determination of arsenic in biological materials is the combination of wet ashing, oxidation t o quinquevalent arsenic, and development of the blue color by using ammonium molybdate and hydrazine sulfate. T h e method was designed t o determine micro quantities of arsenic in samples containing less than 0.1 microgram of arsenic with a sensitivity of 0.01 microgram for use with body tissues. T h e end point was determined with a spectrophotometer at a wave length of 830 to 865 mp. Bricker and Bweetser ( I O ) presented a method for the photometric determination of micro quantities of arsenic. They titrated with ceric sulfate and determined the end point with a spectrophotometer a t 320 m&. ht this wave length, cerium and arsenious ions do not absorb. This appears t o be the initial use of the ultraviolet region of the spectrum for the determination of photometric end points. SUMMARY
Because this is the initial review on pesticides, methods published during 1950, 1951, and 1952 are briefly reviewed, as well as some other reviews just preceding this. The objective wm to cover all methods for pesticides, including insecticides, fungicides, herbicides, and rodenticides, and t o cover determination of the chemicals, formulations, and spray residues. Notification regarding any papers on such analytical methods t h a t have been omitted will be appreciated, as n-ill also notification of papers published during 1953. REFERENCES
(1) Arceneaux, C. J., A x . 4 ~ CHEM., . 23, 906-11 (1951). (2) Assoc. Offic. Agr. Chemists, “Official Methods of Analysis.” 7th ed., 1950.
Averell, P. R., and Norris, hl. V., ANAL.CHEM.,20, 753-6 (1948). Bissinger, U’.E., and Fredenburg, R. H., J . Assoc. Ofic. A g r . Chemists, 34, 812-16 (1951). Blinn, R. C., and Gunther, F. A , ~ N A L .CHEM.,22, 1219 (1950). Bottini, Ettore, and Fantini. Giuseppe, Ann. sper. agrar. ( R o m e ) ,4,453-69 (1950). Bowen, C. V., J . Assoc. Ofic. Agr. Chemists, 33, 774-82 (1950). Bowen, C. V., and Edwards, F. I., Jr., Advances in Chem. Ser.. NO. 1, 198-201 (1950). Bowen, C . V., and Edwards. F. I., Jr., .-irua~.CHEV., 22, 7 0 6 8 (1950). Bricker, C. E., and Sweetser, P. B., Ibid., 24, 409-11 (1952). Buhrer, M. E., Quimica e industria (Sdo Paulo), 16, 169-70 (1948). Bushland, R. C., J . Econ. Entomol., 44,421-3 (1951). Carter, R. H., J . Assoc. Ofic. Agr. Chemists, 33,597-9 (1950). Carter. R. H.. Nelson. R. H.. and Gersdorff. IT. A.. Aduances in Chem. Ser., No. 1,271-3 (1950). Clarke, D. G., Baum, Harry, Stanley, E. L., and Hester, W.F.. AN.AL.CHEM.,23, 1842-6 (1951). Cupples, H. L., Ibid., 24, 1657 (1952). Dalma, G., and Carson, E, T., Anales asoc. puim. Argentina, 38. 164-76 (1950). Dani$h, A. A.; and’lidov, R. E.. Advances i n Chern. Ser., S o . 1, 190-7 (1950). Danish, A, A., and Lidov, R. E., -4y.i~.CHEM.,22, 702-6 (1950). Davidova, Alice, Rend. ist. super. s a n i h , 13,167-74 (1950). Davidow, Bernard, J . Assoc. Ofic. Agr. Chemists, 33, 130-2 (1950). Ibid., pp. 886-94. Downing, George, and Norton, L. B., Ax.4~. CHEM.,23, 1870-1 (1951). du Pont de Nemours & Co., E. I., Bull. 5-51 (1951). Edwards, F. I., Jr., J . Assoc. Ofic. Agr. Chemists, 33, 783-7 (1950). Ibid.. 34. 686-9 (1951). Ibid.: 35; 381-6 (1952). Edwards, F. I., Jr., and Cueto, Cipriano, ASAL. CHEY.,24, 1357-9 (1952). Ibid., 23,1826-9 (1951). Fahey. J. E., and Rusk, H. W., Federal Security .4gency, Washington, Annual Report 1951, pp. 233-4. Fleck, E. E., J . Assoc. Ofic. Agr. Chemists, 33, 760 (1950). J . Econ. Fleming, W. E., Coles, L. TV., and Maines, W.W., Entomol., 44, 310-15 (1951). Fossum, J. H., and Riddick, J. A , , J . A m . Pharm. Assoc., Sci. Ed., 40, 357-8 (1951). Frawles. J. P.. Lam. E. P., and Fitshugh, 0. G., J . dssoc. Ofic.-Agr. Chemists, 35, 741-5 (1952). Ibid., pp. 746-8. Fromm, F., Botan. Gaz., 113,86-90 (1961). Gage, J. C., Analyst, 75, 189 (1950). Gard, L. N., ANAL.CHEM.,23, 1685-6 (1951). Garhart, M. D., Witmer, F. J., and Tajima, Y. A., Ibid., 24, 851-7 (1952). Giang, P. A., and Hall, S. h.,Ihid., 23, 1830-4 (1951). Ginsburg, J. M., J Econ. Entomol., 39, 174-7 (1946). Graham, J. J. T., J . Assoc. Ofic. Agr. Chemists, 33, 755-8 (1950). I b i d . , 34,667-70 (1951). Ihid., 35, 365-6 (1952). Granger, C., and Zwilling, J. P., Bull. SOC. chirn. France, 17V, 873-6 (1950). Guha, S.K., I n d i a n J . Pharm.. 12,261-2 (1950). Gunther, F. A., and Blinn, R. C., Advances in Chem. Ser., NO.1, 72-87 (1950). Gunther, F. A., and Blinn, R. C., AXAL.CHEM.,22, 1460 (1950). Gunther, F. 4.,Blinn, R. C., Kolbesen, M. J., and Barkley, J. H., Ibid., 23, 1835-42 (1961). Gunther, F. A., and Miller, 51. E., Advances in Chem. Ser., KO.1, 88-92 (1950). Hall, S . 4 . , J . Assoc. Ofic. Agr. Chemists, 33, 761-3 (1950). Hall, S. A,, Stohlman, J. W.,and Schechter, M. S., A K ~ L . CHEM.,23, 1866-8 (1951). Haller, H. L., Advances in Chem. Ser., No. 1, 6&71 (1950). Haller, H. L., Soap S a n k Chem., 25 ( 6 ) , 127-9 (1949). Harris. T. H.. Adbances i n Chem. Sei-., No. 1, 266-70 (1950). Harris, T. H., J . Assoc. ODc. Agr. Chemists, 34, 672-4 (1951). 1 Ibid., 35, 376-7 (1952). (58) Hartsell. Albert, Adinnces i n Chem. Ser., S o . 1, 99-101 (1950).
V O L U M E 2 5 , N O . 1, J A N U A R Y 1 9 5 3
41
(59) Hartzell, Albert, and Storrs, E. E., Contrib. Boyce Thompson Inst., 16, 47-53 (1950). (60) Hasselbach, H., and Schwabe, K., Z . anal. Cheni., 132, 94-104 (1951). (61) Heagy, A. B., J . Assoc. O ~ CI g. v . Chemists, 33,764-9 (1950). (62) Ibid.. 34.674-7 119513. lbid.: 35. 377-51 (1952). Hillenbrand, E. F., Sutherland, JT. W., and Hogsett. J. Pi'., A K A L . (?HEM., 23, 626-9 11951). Hirt, R. C., and Gisclard, J. B., Ibzd., 23, 185-7 (1951). Hornstein. Irwin, Ihid 23, 1329-30 (1951). Ibid., pp. 1330-1. Hoskins, W. &I., and Messenger, P. S., Adrances i n Chem. Ser., X o . 1, 93-8 (1950). Hoskins, TV. hI., Witt. J . M., and Erwin, IT, R., .Isa~. CHEM., 24, 555-60 (1952). Jakobs, H., and Hong, 0. Ta., Chem. Weekhlad, 46, 501-4 (1950). Jones, H. A., Ackermann, H. J., and Webster, XI. E., J . dssoc. Ofic. Agr. Chemists, 35, 771-50 (1952). Jones, L. R., and Riddick, J. -I., A N ~ LCHEY., . 24, 569-72 (1952). . Chemists, 35, 368-71 (1952). Kelsey, David, J. Assoc. O ~ CAgr. Kenyon, IT'. C., A i s . h ~CHEY., . 24, 1197-8 (1952). Ketelaar, J. .1.A , , and Hellingman, J. E., Ibid., 23, 646-50 (1951). Iiingsley, G. R., and Schaffert, R. R., Ibid., 23, 914-19 (1951). Krauze, St., and Rzymowska, C. J., Roczniki Panstwowego Zakladu Hig.,1, 439-86 (1950). LaClair, J. B., J . Assoc. Ofic. Agr. Chemists, 33, 758-60 (1950). Ibid., 34, 670-2 (1951). Ibid., 35, 372-6 (1952). Lehman, A. J., Bull. S.Y . I c a d . Med., 25, 382-7 (1949). Lowen, wr.K., A N A L . CHEM., 23,1846-50 (1951). Lowen. TV. K.. and Baker. H. M..Ibid.. 24. 1475-9 11952). Luther, H., Lampke, F., Goubeau, J., and Rodewald, B. W., 2. Naturforsch., Sa, 34-40 (1950). Mann, H. D., and Carter, R. H., ASAL. CHEY.,23, 929-30 (1951). hfarquardt, R. P., and Luce, E. N., Ibid., 23,1484-6 (1951). Mellini, Franco, Chimica (Milan),5,335-7 (1950). Mever. R.. Mitt.Gebiete Lebensm. Huo.. 38. 151-60 (1947). hlifler,'V. L., Polley, Dorothy, and G%ld,'C. J., AN'.~L.CHEM., 23, 1286-8 (1951). Monnier, D., Roesgen, L., and Nonnier, R., A n a l . Chim. rlcta, 4, 309-15 (1950). Xolan, Kenneth, and Vilcoxon, Frank, Agr. Chem., 5 (11, 53-74 (1950). Korton, L. B., and Schmalzriedt, Barbara, A K ~ LCHEM., . 22, 1451 (1950). Odencrantz, J. T., and Rieman, William, Ibid., 22, 1066-7 (1950).
(94) O'Keeffe, Kathryn, and .4verell. P. R., Ibid., 23, 1167-9 (1951). (95) PagBn, C., and Hageman, R. H., J . Council Sci. I n d . Research, 18,121-3 (1950). (96) PagBn, C., and Hageman, R. H., Science, 112, 222 (1950). (97) Patterson, J. D., J . Assoc. Ofic. Agr. Chemists, 33, 788-90 (1950). (98) Ibid., 35,388-91 (1952). (99) Payfer, R., Ibid., 35,371-2 (1952). (100) Polen, P. B., and Silverman, Paul, h l u . 4 ~ . CHEM., 24, 733-5 (1952). \----,-
(101) Prickett, C. S., Kunae, F. >I.,and Laug, E. P., Fed. Amer. S O ~ . E r p t l . Biol. Fed. Proc., 9 (1, Pt. l ) ,309 (1950). (102) Prickett. C . S., Kunze, F. XI., and Laug, E. P., J . dasoc. Ofic.
Agr. Chemists, 33,880-6 (1950). (103) Ramsey, L. L., Ibid., 33, 608-610 (1950). (104) Ibid., pp. 1010-16. (105) Ramsey, L. L., and Clifford, P. A,, Ibid., 32,788-97 (1949). (106) Ramsey, L. L., and Patterson, W'. I., Ihzd., 34,527-31 (1951). (107) Ripper, W.E., Greenslade, R. >I,, and Hartley, G. S., Brdl. Entomol. Research, 40 (Part 4), 481-501 (1950). (105) Romano, E., Ann. stat. chim.-agrar. sper. R o m a , Ser. 3, No. 26, 12 (1950). (109) Rooney, H:A., J. Assoc. Ofic.S g r . Chemists, 34, 677-80 (1951). (110) Ibid., 35, 386-7 (1952). (111) Roth,H., 2 , a n a l . Chem., 131,347-55 (1950). (112) St. John, J. L., Advances i n Chem. Ser., S o . 8 (1952). 1113) Samuel. B. L.. J . Assoc. Offic. Agr. Chemists, 35,391-2 (1952). (114) Schechter, M. S., ANAL.C H E M . , ~538 ~ , (1951). (115) Schechter, Xl. S.,and Hornstein, Irwin, Ibid., 24, 544-8 (1952). and McClellan, D. B., Ibid., 24, 1194-5 (1952). (116) Schreiber, .4.&4., (117) Shell Chemical Corp. and Julius Hyman & Co., Bull. 1-146 (1952). (118) Simmons, W. R.. and Robertson, J. H., I h i d . , 22, 294-6 (1950). (119) Stammer, W. C., J . Assoc. Ofic. -4gr. Chemists, 33, 607-8 (1950). (120) Sun, Y.-P., J. Econ. Entomol., 43,45-53 (1950). (121) Sun, Y.-P., and Sun, J.-Y., Ibid., 45,26-37 (1952). (122) Tamamushi, R., and Tanaka, N.,Repts. Radiation C h i m Research I n s t . Tokyo Unia., 5,41-3 (1950). (123) Tillson, A. H., Eisenberg, W. V., and Wilson, J. B., J . Assoc. Ofic. Agr. Chemists, 35,459-65 (1952). (124) Toops, E. E., Jr., and Riddick, J. -I., AN.iL. CHEY.,23, 1106-10 (1951). (125) Tufts, L. E., Darling, 0. W.,and Kimball, R. H., J .4ssoc. Ofic. Agr. Chemists, 33, 976-86 (1950). (126) Wasicky, Richard, A n a i s fuc. f a r m . e odontol., univ. Sad Paulo, 7,263-96 (1949). (127) Weber, Edgar, 2. anal. Chem., 132, 26-33 (1951). (125) Wichmann, H. J., J . ds.soc. Ofic. Agr. Chemists, 33, 585-91 (1950). (129) Wilson, John B., Ihid., 35,455-8 (1952).
PETROLEUM HARRY LEVIN The Texas Co.,Beacon,
A
d C A S be seen in the four previous annual reviews and generally in the field of analytical chemistry, the adaptation of instrumental methods to the solution of various problems continues t o be the major trend in the analytical phase of petroleum technologr. This is apparent again in the following review, which covers the literature for a period of one year from that covered in the previous reviex (98). CRUDE OIL
.4n apparatus and procedure for determining water in wateroil emulsions, based on their dielectric constants, were described by Robinson and Ebertz ( 1 3 7 ) . Schuldiner (147) established the source of harbor pollution from the contour and fluorescence of the spots formed in paper chromatography of crude oil and its products. Lockwood et al. (101) assayed crude oil in new e q u i p ment comprising a spinning band column for atmospheric and vacuum distillations, a spinning auger still for molecular distillation, and a n all-glass equilibrium flash vaporization unit. A laboratory recirculating equilibrium still for flash vaporization
1%.'
Y
of petroleum crude oil or its fractions was described by Othnier et al. (120), who evaluated its characteristics at and below atmospheric pressure and temperatures to 357 ' C. 645
Hall ( 5 7 ) determined dissolved oxygen in petroleum fractions polarographically by measuring the diffusion current at - 1.6 volts; the precision was &2 mg. per liter of sample in an elapsed time of 15 minutes. Luft (102) determined the oxygen content of gases by passing them through tubes kept in magnetic fields of different intensities, voltage being proportional t o the oxygen concentration of the sample. Cipriano and Riggs (23) determined oxygen in flue gas from a catalytic cracking unit regenerator, by instrumentation employing the paramagnetic properties of oxygen for the measurement. MeArthur (105) determined low concentrations of oxygen in gases by the change in chromous ion concentration of dilute solutions of chromous chloride through which measured volumes of gas sample were passed. Taylor and .4lexander (16%) compared the results for oxygen in buta-
