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SIS iques: and tis its, io'logy, ces, is post & $13.00 + >F YTICAL 210-J jA CENTURY OF ANALYTICAL EXCELLENCE pesticides, Their Analysis and the AOAC: An Overview of a Century of Progress (1884-1984) MALCOLM C..BOWMAN1 ' M c. Bowman and Associates, Consulting Scientists and Laboratories, PO Box 1302, Pine Bluff, AR 71613 The Early Years (1884-1942) In (bis centennial year ofthe founding ofAOAC, it is almost impossible for us to comprehend just what it was like to.live in the year 1884. Therefore, the reader is asked to digress briefly to reflect on events and conditions in the United States at the time our Association was founded. Such reflections nill emphasize the incredible growth of science and technol ogy as well as the rapid development of the American nation and world civilization. . Visualize the year 1884: The population ofthe United States was about 55 million and the national debt stood at the stag gering figure of 2 billion dollars. Grover Cleveland had just been elected to succeed Chester A. Arthur in the White House, and there were 38 stars in our flag. There was talk about opening up the Oklahoma Territory to settlement, but this would not occur for 5 more years. The Industrial Revo-. lutiOn had gained full momentum), and a modem engineering marvel, the Brooklyn Bridge, Was opened last year. Only-5 years had passed since Alexander Graham Bell had carried on the first telephone conversation, and 13 more years would pass before Marconi could successfully send short-distance radio messages. Although railroads were fully operational, automobiles were still in the experimental stage (Daimler; Benz). Some recent inventions were barbe.d wire (Glidden), the phonograph and incandescent lamp (Edison), electric fan (Wheeler), electric flat iron (Seeley), steamturbine (Parsons), and the fountain pen (Waterman) (1). These developments are mentioned to emphasize the fact that the technology and apparatus required for modem pesticide research were just beginning to emerge; only a very small percentage of the devices currently used in research existed in the year 1884. Broad advances in the areas of chemistry, physics, medicine, communications and information, engineering, and transporation slowly and steadily provided the building blocks for ourpresent capabilities. Also, during the past several decades have seen that requirements for national defense, space coloration, competition among nations for world markets, jwblic demand for an improved quality of life and a safe 'wironment have accelerated the advancement of science, ins" pestic'de formulations were concoctions contain- ne or more of the following ingredients: tobacco, soap, ^Pentine, various oils, kerosene, sulfur, lime, phosphorus, py c"nc cblride, arsenic, hydrocyanic acid, phenol, cresol, turn, and naphthalene (2). Paris green, an aceto-meta'omm fCOpper tCu(CH3C00)2-3Cu(As02)J, had come into bin^j011 UsaSe us an insecticide. Bordeaux mixture, a com?^me and copper sulfate, was discovered to have dt^1 . Properties by Millardet in France in 1883. Borpt0gn mixtUre Paris green could be safely combined to erties L 3 Spray w`[tl both insecticidal and fungicidal proparsenj'te nt*on purple, a mixture of calcium arsenate, calcium r 'and other products including a small amount of dye, 0Iumended as a substitute for Paris green. The name ^lul rCtor' division of Chemistry, Food and Drug Administration, r *or Toxicological Research, Jefferson, AR; retired 1981. "London purple" was given to the material because it was originally an arsenical by-product ofthe magenta dye industry in London (2). Oddly enough, DDT had been synthesized by Zeidler in Germany in 1874 but its insecticidal properties would not be discovered until 1939. This list of pesticides appears completely inadequate when compared with the many products, available to us today. However, if we begin with the earliest records of pesticides found on stone tablets which described the use of red squill (dried bulbs of the lily family) as a rat poison, include Homer's description of the use of sulfur for fumigation and other forms of pest control in about 1000 BC, and all other discoveries up to the use ofturpentine to repel and kill insects in 1787 (2), it becomes obvious that more progress was made during the'nineteenth century than in all previously recorded history. In the year 1984, even a cursory view of the history of pesticides shows that the knowledge, development,.and usage oi'these substances are increasing exponentially with time. . Conditions which led to the organization ofthe Association of Official'Agricultural Chemists (AOAC) centered around the new chemical fertilizer industry which had begun to fluorish late in the nineteenth century. Several states passed leg islation which required that the N-P-K content be placed in. each bag. Consequently, chemists from government and-' industry made three separate attempts in 1880 and 1881 to coordinate their work; however, all failed'because ofdisputes over the choice of methods. In 1884, J. T. Henderson, Com missioner of Agriculture, State of Georgia, called a confer ence in Atlanta to organize an association to adopt uniform analytical procedures. This group wrote a constitution which allowed only.regulatory chemists to vote on the adoption of methods; however, others.couli participate in discussions and investigations. The fertilizer industry subsequently rec ognized the urgent need for uniform methods and recom mended that the constitution be adopted (3). Thus, AOAC was bom later that same year at Philadelphia. From this simple beginning, AOAC (known as the Association of Offi cial Analytical Chemists since 1965) has grown to encompass the development and adoption of uniform methods for vir tually every field of the analytical sciences pertaining to agri culture, public health and safety, consumer protection, and quality of the environment. The Association has quickly out grown its present name and is no longerjust an organization for chemists but is truly an Association of all analytical sci entists. . Prior to writing this article, the author searched the archives ofAOAC at Arlington, VA, and found that the early activities of the Association were published as proceedings by the U. S. Department of Agriculture. Although nothing pertaining to the analysis ofpesticides could be found before 1899, some of the entomology reports were quite interesting and should be briefly shared with the reader. An extensive report was presented in 1886 concerning the production and use of the insect powder "Buhach" (4). The product was produced at Stockton, CA, from dried flowers ofPyrethrum cinerariafolium grown on 300 acres in Merced County, CA; and sold wholesale for 45 to 50 cents a pound. The application of the HARTOLDMON0030331 ,?06 BOWMAN: J. ASSOC. OFF. ANAL. CHEM. (VOL. 67, NO. 2, 1984) material as a powder, tea, or tincture was vividly described along with its insecticidal'effects. Several testimonials were presented concerning its low mammalian toxicity as follows: 1) "Workmen in the manufacturingplant continuously breathed the fine dust for several hours at a time and never suffered adverse effects,' ' 2) ` `One teaspoonful ofthe alcoholic extract of Buhach was. administered to a certain person afflicted with tape-worm; the dose was repeated each hour for ten consec utive hours, with the effect of removing the tape-worm with out in the least degree injuring the patient'' 3) At the stable ofthe Buhach plantation several tons of the dried stems were fed to the horses; "the latter appeared to relish it very much" and no injury could be discovered. Although these testimo nials were useful in 1886 and contained many basic elements of modem toxicology, they .would hardly be admissable by regulatory agencies as good laboratory practice experiments in 1984. ' In entomology reports of 1886 (5), the blister beetle (Can- tharis nuttalli Say) was reported to cause great damage to bean crops in North Dakota; the remedy was to drive them into windrows of straw which were then burned. In another report, the wooly aphis (Schizoneura lanigera) was causing extensive damage to apple trees in California; the remedy was to spray with a mixture containing one-half pound of tobacco and one-half pound of whale oil soap per gallon of water. The mixture was to be applied at about 130F and the process repeated in about one week. A comparison of these remedies with current practices will emphasize the progress that has been made in pest control during the past century. Atthe 15th Annual Convention of-the AOAC in 189B, the president of the Association recognized' that the value of products such as tobacco powder and extracts, which were coming into extensive use, was chiefly'dependent on. the nicotine content and called for methods to determine this ingredient. Furthermore, methods for arsenical powders and fungicides were also needed; therefore, he- called for the appointment of a referee to investigate methods for the valu able ingredients in these products' (6). Thus, the following, year (1899), the first AOAC report on fungicides and insec ticides was presented to the convention,by Referee L. A. Voorhees. This report included methods for determining nicotine, arsenic, cyanogen, copper, and formaldehyde which specified volumetric or gravimetric techniques after various chemical reactions and manipulations (7)1 With this modest beginning, a continuous effort has been sustained by AOAC to obtain, develop, validate, and adopt analyticalprocedur.es for pesticides that are legally and mutually acceptable to both government and industry. These methods were initially pub lished annually in the Proceedings ofthe Annual Meeting of the AOAC and subsequently in the Journal of the AOAC. which succeeded it in 1915 and has appeared continuously since its inception. The Journal began accepting contributed articles in 1923, and since 1920, AOAC has also published Official Methods of Analysis every 5 years. Through the years, these publications have been invaluable as references to accepted procedures for pesticide analysis; the Journal has also provided for the rapid publication of new methods not yet subjected to the rigorous evaluation required for offi cial adoption. - From the turn of the century until the. beginning of the synthetic organic pesticide era in 1942, many new products and ideas were advanced for pest control.'Various new com pounds ofarsenic came into use and new fumigants included p-dichlorobenzene, ethylene oxide, ethylehe dichloride, and ' methyl bromide. Geraniol was found to atyfact the Japanese beetle, and alkyl phthalates to repel insects. Cubd was being tested as an insecticide, and sesame oil \yas discovered synergize pyretbrum. The airplane was first .used at T lo lMy compounds of thi: ,,ial use- These che, OH, to distribute insecticides in 1921. The age of synth^' organic pesticides was beginning to dawn with the comm " cial production of pentachlorophenol in 1936 and the disc ery of hexachlorobenzene in 1941 (2). The development \ blooded animals and le: 1 i9J0s, another clast carbamates came into u new analytical chemical techniques during this period o ' ceeded at a snail's pace; only the electrolytic determinati^ -ounds soon developed. ^Concurrent with th< of copper was added to the conventional volumetric aj ^phosphorus, and. gravimetric methods for pesticide analysis. cfherbicides were also t On the regulatory scene, an arsenic poisoning incident involving some 6000 persons in England who had consumed contaminated beerresulted in about 70deaths. This prompted the British to establish a tolerance of 0.01 gr (grains) A'S,(U lb of solid food (1 ppm = 0.007 gr/lb) in 1903. A Federal Pure Food and Drug Act was passed in 1906; however, proof that an adulterated food was a potential health hazard was required prior to corrective action. The Federal Insecticide Act was passed in 1910, and in 1927, the Food and Drug Administra tion established a tolerance of0.025 gr AsjOj/Ib for fruits and vegetables in interstate commerce. Later, in 1923, accurate methods for low levels of lead became available and a toler ance of 01025 gr Pb/lb of commodity was also set because of the widespread use of lead arsenate. The Food, Drug and Cosmetic Act of 1938 provided more extensive protection to the consumerthan the previous act of1906, because provision was made to establish safe tolerances for deleterious sub-, stances added to foods (2). It should be pointed out that Harvey W. Wiley was a key figure in the founding and development ofAOAC. Dr. Wiley, supported by the.official methods of AOAC, was primarily responsible for the'passage of the Pure Food and Drug Act of 1906. As the first administrator of this Act, he came under severe pressure from industry; however, even after his retire ment from the Department of Agriculture in 1912, he contin ued to speak out for consumer protection until his death in 1930(3). ' -pnatedphenoxy acids, phenols, dinitroanilines, crs. Doting this same j other compounds of pi rodenticides, repellants, icides, .nematocides, -1 synergists, defoliants, . tides, mulloscicides, etc to those already in use p compounds available for therewas an exponential chemical procedures wh for determining residue: their admixtures. . As we entered the er 1942, the development o notkept pace with the re theaddition of several hu during the 1940s and IS enlists seemed almost area ofresidue analysis Instrumentation for absorption spectrometr ' the 1940s and was very formulations. Polarogra cations. However, thest the analysis of residue: As we entered World War II and the era of synthetic organic pesticides, most of the analytical chemical procedures were still confined to the analysis of formulations except for the As and Pb residue determinations previously mentioned. Analytical technology required for trace-level analyses was. simply not available to keep pace with our . knowledge of chemistry and the development of pesticides. samples. The most wide! were based on the force by a spectrophotometrii visible portion of the s; classical Schechter-Hali cll-Norris method for pa developed during this-p today, is the enzymatic i bition (10). This metho The Era of Synthetic Organic Pesticides (1942-Present) change in pH, coloiime DDT is probably the most widely known, used, and abused for the determination o: pesticide in all recorded history. Although first synthesized to measure the extent o in 1874, it was- not tested as an insecticide until 1939. A small to such compounds. amount of the compound was brought into the United States - Wost analyses for res in 1942 and tests soon revealed its outstanding insecticidal sleP process involving, properties. -The author has-selected this event as the begin ning of the era, of. synthetic organic pesticides. Production substrate, 2). separatior (known as cleanup), ai was begun almost immediately and essentially the entire ofl- nsidues. Considerable j put was used by the armed forces to control body lice, t"0*' quitoes, and other pests during World War II. Large quanti, ^Ps during the 1940s a^diments of chromatog ties of the pesticide swere produced for post-war use, * soon an entire family of synthetic organochlorine compd"1^ was in widespread use. In addition to DDT, this class chemicals included chlordane, toxaphene, lindane, metho i eP would prove to b ttsidues in the future. ' "oans color (12), is usu T.'jhromatography. His chlor, aldrin, dieldrin, heptachlor, and others. Residues many ofthese compounds were highly persistent in the en *be separation of s plating them throu; ronment. Then in about 1946, synthetic organophospb . j*d plant pigments -I^ds by a kind of liqu insecticides such as parathion and TEPP, produced by f man research, were also introduced into the United Sta j| *phy. Whether Tsv HARTOLDMON0030332 BOWMAN: J. ASSOC. OFF. ANAL. CHEM. (VOL. 67, NO. 2, 1984) 207 ie oil ^as discovered ^ was first used at Troy 21. The age of synthei* dawn with the comm*,, il in 1936 and the discov. 2). The developmeni of i during this period pt^. lectrolytic determinatio, entional volumetric ay lalysis. ;enic poisoning incideg '.land who had consumed 70 deaths. This prompted of 0.01 gr (grains) As,0/ ) in 1903. A Federal Pun 906; however, proof(fy ealth hazard was required eral Insecticide Act was od and Drug Administiagr AsjOj/lb forfruits aid Later, in 1923, accurate me available and a tolerj was also set because d te. The Food, Drug and e extensive protection b >f 1906, because provision ices for deleterious auts Many compounds of this general class also quickly came into neral use. These chemicals differed from organochlorine compQUuds in that they were generally more toxic to warm blooded animals and less persistent in the environment. In the 1956s > another class of synthetic insecticides known as carbamates came into use, and a large family of these com pounds soon developed. , * Concurrent with the development of organochlorine, organophosphorus, and carbamate insecticides, many classes of herbicides were also being produced. These included chlo rinated phenoxy acids, S-triazines, phenylureas, carbamates, phenols, dinitroanilines, chlorinated benzoic acids, and oth ers. During this same period of about two decades, many other compounds of pesticidal activity came into use as rodenticide's, repellants, attractants, sexual sterilants, fung icides, nematocides, acaricides, bactericides, miticides, synergists, defoliants, fumigants, growth regulators, algi- cides, mulloscicides, etc. All of these chemicals, when added to those already in use prior to 1942, constitute a plethora of compounds available for pesticidal evaluation and use. Hence, there was an exponential increase in the demand for analytical chemical procedures which were both specific and sensitive for determining residues of these individualichemicals and. their admixtures. As we entered the era of synthetic organic pesticides in 1942, the development of analytical chemical technology had not kept pace with the requirements for it. Furthermore, with the addition of several hundred new pesticides ofmany classes v ey W. Wiley was a key ent.of AOAC. Dr. Wiley, of AOAC, was primarily during the- 1940s and 1950s, problems facing analytical sci entists seemed almost insurmountable, particularly in the area ofresidue analysis for regulatory purposes. Pure Food and Drug Ad fthis Act, he came unde aver, even after his retire ulture in 1912, he contmtection until his death ie ,. ie era of synthetic organ# hemical procedures were mulations except for s previously mentioned. ' trace-level analyses wa : with our knowledge pesticides. sticides (1942-Preseat) * known, used, and abus^ Instrumentation for infrared, visible, and ultravioletabsorption spectrometry became generally available during the 1940s and was very, useful-for the analysis of pesticide formulations. Polarography was also used in limited appli cations. However, these methods were not easily adapted to the analysis of residues in food, feed, and environmental samples. The most widely used residue methods ofthis period were based on the formation of a colored product followed by a spectrophotometric measurement of its intensity in- the visible portion of the spectrum. Examples of these are the classical Schechter-Haller method for DDT (8) and the Avercll-Norris method forparathion (9). Anotheruseful procedure developed during this period, which remains equally useful today, is the'enzymatic method based on chlolinesterase inhi- jtion (10). This method, which may now be quantified by 5 ane `n PH, colorimetrically or manometrically, is useM ! r "e determination of organophosphorus insecticides and Jthough first synthes^ sticide until 1939. A so1 ght into the United StaW measure the extent of any exposure of humans or animals 0 such compounds. a ^ost analyses for residues of pesticides consist of a three- > outstanding in?ecUCV, i this event as the ic pesticides. Produ ; essentially the eotift sub fTMCeSS involving, 1) the extraction of residues from the ft* rale> 2) separation of the residues from coextractives lesid*11 ^ c^eanuP)> and 3) measurement of the extracted s(e ^'.Considerable progress was made in allthree ofthese ,o control body lice> J .rid War n. Large 9"^ >d for post-war use, - rganochlorine com|r ^ mi w DDT, Uns-eJJ^ niditne*11TM8 and 1950s; however, experiments with Sle nts chromatography primarily for use in the cleanup fesidu U-k* prove t0 be the key to successful analyses of means'* T the future` Tswett (U). whose name in Russian as chmC r 's usuaDy credited with the process known phene, lindane, me Wish t[)l'latoSraphy. His experiments, reported in 1906, dealt and others. ^ J| perco] (.5eparatin solutions of colored plant pigments by ;hly persistent in > ciored^em throu8h columns of solid adsorbents. The .theticorganopho^l; hands h ^lant- P'ments were separated into distinct colored TEPP, produced Wg | lraPhv liquid-solid or liquid-adsorption chroma- :d into the United y. whether Tswett's coining of the term chromatog raphy (color writing) alluded to the colored bands on the column or to his own writings is not known. As early as 1512,.Brunschwig (13) had described aprima- tive form pf.gas chromatography for purifying ethyl alcohol (14,15). Also, in this very brief review of chromatography, the author is compelled to cite instructions on this subject given by the Supreme.Sciemist erfthe Universe, in about 1491 BC; "So-Moses brought Israel from the Red Sea, and they went out into the Wilderness of Shur; and they went three days in the wilderness, and found no'water. And when they came to Marah, they could not drink of the waters of Marah, for they were- bitter; therefore the name of it was called Marah. And the people murmured against Moses, saying `What shall we drink'? And he cried unto the Lord; and the Lord shewed him a tree, which when he had cast into the waters, the waters were made sweet: there he made for them a statute and an ordinance, and there he proved them' ' (16). Regardless of where the reader chooses to put the origin of the chromatographic process, it is clear that the concept, as applied to analytical chemistry, was dormant until the mid- 1940s when adsorptioH columns came into use for separating pesticide-residues from coextractives which interfered with the analysis. Liquid-liquid chromatography, described in 1941 (17), was later developed into paper chromatography (18). An early application of paper chromatography to pesticide analysis was that of Metcalfand March (19) forparathion and related phosphate esters. Although Martin and Synge (18) had presented the basic principles of gas chromatography (GO in their 1948 paper, little was done to develop the pro cedure before the work ofJames arid Martin (20) in 1952. GC then developed very rapidly and became one ofthe outstand ing methods for analysis. Its usefulness for the analysis of pesticides was limited to formulations because the detectors were not specific; however, a combustion furnace, titration cell, and coulometer were soon placed .in tandem with the gas chromatograph for the analysis of pesticides which con tained chlorine or sulfur (21). In brief summary of the events during the 20-year period leading into the 1960s, hundreds of synthetic organic pesti cides of many chemical classes became available for use; sensitive and specific methods were required for -their anal ysis, particularly from the residue aspect. -Infrared, visible, and ultraviolet spectrometry became common, and many colorimetric methods were developed. Outstanding progress was made in the area of separation science with the devel opment of liquid-solid column chromatography, paper chro matography, and gas-liquid chromatography. Sensitivity for analyzing residues was brought from the milligram to the microgram level. A popular guide to the analysis of such residues during that period was the classical textbook of Gunther and Blinn (22). In reviewing the archives for this period at AOAC, the author found that the names of the Associate Referees would literally constitute a Who's Who in pesticide analysis. AOAC had indeed been hard at work, and many procedures based on new technology had appeared in the Official Methods ofAnalysis of the AOAC by 1960. It was also noted that the old section heading "Insecticides and Fungicides" was replaced by "Economic Poisons" in 1950. However, this term was short-lived and, in 1955, under the editorship of William Horwitz, the present category "Pesti cides" was adopted. The Journal of the AOAC and meetings and workshops of the Association continued to provide for ums for the development of analytical procedures for pesti cides. ' . By the mid 1960s, several events had occurred which would change the future of pesticide analysis. First, a highly sensi- HARTOLDMON0030333 U XMh L' \ ft \l- BOWMAN: J. ASSOC. OFF. ANAL. I live detector based on the ability ofcertain functional groups, such as halogens, nitro groups, peroxides, and others, to capture low energy electrons was reported by Lovelock and Lipsky (23). The detector was almost immediately coupled with a gas chromatograph and used for the analysis of chlo rinated pesticides (24, '25). This system, known as electron capture gas chromatography (EC-GC), was shown to increase the sensitivity for analyzing halogenated pesticides by a fac tor of 10,000, making the detection of picogram amounts possible. Second, Rachel L. Carson, an American biologist and science writer, published her book Silent Spring in 1962, which aroused public and government concern about the adverse effects of environmental pollutants. Susequently, large sums of public funds were made available for research, monitoring, and regulation of such materials which included pesticides. These two events more than any others set the scene for extensive work in the area of pesticide analysis. In the 1950s, thin layer chromatography (TLC),' which combines desirable features of liquid-solid column chroma tography with paper chromatography, was introduced as an analytical procedure. At first, the method was considered only qualitative or semiquantitative at best. However, pioneering work by Beroza et al. (26) and others has brought the technique to acceptable levels of accuracy and precision for quantitative analysis. The method is also well suited for confirmatory tests, Also, beginning in 1965, Bowman and Beroza published a series of papers which described the usefulness of partition values (p-valuesj in selecting solvents forpesticide extraction, cleanup, and'confinnation ofidentity of the residues (27-29). The EC-GC system previously described for halogenated pesticides responded poorly to the general class of organophosphorus pesticides which were widely used.-This gap in methodology was bridged by the development of the alkali flame ionization detector (AFID) of GiuSrida (30) and the flame photometric detector (FPD) of Brody and Chaney (3.1), which .was sensitive and- specific for phosphorus or sulfur. The FPD was extensively evaluated for gas'chromatographic analysis of phosphorus and sulfur- containing pesticides by Bowman and Beroza, and in 1968, they reported an improvement of the detector which simul taneously presented phosphorus- and sulfur-specific chro matograms on separate channels and also provided for an estimation of the molecular P and S content of the gas chro matographic peak (32). Thousands of publications based on gas chromatographic analysis of pesticide residues appeared in the scientific literature during the ensuing decade. Many . of the compounds not directly amenable to gas chromatog raphy were derivatized or otherwise modified prior to anal ysis. : One ofthe major deficiencies in gas chromatographic meth odology for pesticides bad been the absence of detectors sensitive and specific for nitrogen-containing compounds. Coulson (33) addressed this need by placing an electrolytic conductivity cell in tandem with a reduction furnace (nickel catalyst; hydrogen carrier gas) which converted the N-cora- pounds to ammonia. This system was evaluated by Patchett (34) and others and further developed by Hall (35). Although sensitivities to 0.1 ng organic nitrogen with about a 30,000:1 selectivity have been reported (34), operation of the system in the N-mode has not been as popular as the Cl-mode. Another detector useful for the analysis of N-containing com pounds is the "rubidium-sensitized" system which responds to bothN- and P- containing compounds. After experimental use for several years, the detector became sufficiently reliable for routine use after the rubidium salt was placed into an electrically heated bead and the low hydrogen flow (1-3 mL/ min) was precisely controlled (36). Both the electrolytic ^ ductivity and rubidium-sensitized detectors are useful for analysis of residual N-containing pesticides such as carba mates; however, the instability of many of these compound may require derivatization or an alternative means of analy. sis. A comprehensive series of reviews of the state-of-theof pesticide analysis was edited by Bowman in 1975 (37-10!* prides, the synthet becoming widely ac jJUgh quality colum <* , .f resolution and h Sample high): Jdoped isthejsomer # hloro-p-dtoxtn (2,3 ^ negative c Experts in the field dealt with the analytical chemistry ofth pnoted that 22 TCDD h various classes of chemicals, types of methods, samnlin6 p - - such as DDT and alternative means to achieve the desired biological con trol. In writing on the subject of carbamate analysis, which remains one of the most difficult classes, H. W. Dorough said, "One of the most disturbing aspects of carbamate res idues analysis involves what might be referred to as labora Tjjyl ethers, and chlori Lvn to interfere in pre> ij{2,3,7;8-TCDD can be lielow parts-per-frillion jjjjljty of methodology tc tory-specific methods." Dorough went on to explain Hat ,,fresidues imposes an a while the laboratory which developed the method continued tdlogists, i.e.; the task t to report good results, others simply could not make it v/oik This phenomenon was attributed primarily to the omission of a vital point in the residue procedure which, on the surface jjjjrance to humans and $n excellent review of jjipesticides- and their r mightappearinsignificant (40). Most analytical chemists have encountered this problem many times, and its continued pres ence emphasizes the need for wide participation in the inter laboratory activities of AOAC. Because of the extensive col |jjl (46). Pesticide Ass st available at modera fro'tection Agency, Was sow required for pesticic laborative tests among laboratories which are required for the adoption of a procedure, there are no "laboratory-spe cific" official methods of AOAC. The adoption of official lion; therefore, it is anti sisterials will gain appre jibe members and offi methods does take time and, of necessity, lags the.state-ofthe-art; however, this period can be held to a minimum by wide laboratory participation in the process. In this same series of reviews (37-39), the editor empha ij;the accomplishments ctntury.Many ofthe sigi jpalya's previously cite> tktAOAC and/or in th sized two problems that still require our attention (41). First, residues of pesticides in environmental samples cannot be' analyzed by present methods unless they are extracted from the substrate, and the concern for efficient extraction ofsuchresidues has not been commensurate with its importance. Through the years, extraction techniques have progressed from "surface stripping" With nonpolar solvents, through blending with solvents of medium polarity, to exhaustive procedures using more polar mixtures via reflux or Soxhlet were simultaneously be: rialytical sciences. The AOAC will continue to i "tfihods recogriizedby g Continued support of t atJlaiuing members, an Mhe laboratory collate sbility ofreliable and ac ^.sciences in the futui extraction. Recoveries of biologically incorporated orweath- ered residues have increased as techniques improved. How ever, results from tests with radiolabeled pesticides have '' Epilog: A revealed that significant amounts ofthe residual radioactivity remained unextracted even with use of the most rigorous techniques (42, 43). Every effort should be made to develop and use efficient extraction procedures; the nature and toxi cological significance of the bound residues should also hr determined. Second, tentative identification of pesticide res idues in samples of unknown treatment history is often made on the basis of one determinative procedure! It is impede that such identifications be confirmed (or rejected) by several alternative procedures. Many residues reported in the P*st could be erroneous because the analyst failed to perform th* confirmations. Techniques useful for confirmatory tSls 2fC gas chromatography (GC) employing a variety of detector5 and/or columns of different polarities, TLC, p-values, den. vatization, liquid chromatography (LC), GC or LC inst^ Mr faith that humai tofive and work togethe survive and develop, th % members of AOAC Mens to the members WM). The current rap pater science, commun space-age technology ^even imagine what th be a century from vbehighly sophistica kPe that you have acl ost of the problems r ^es and all biologies ments coupled to a mass spectrometer (MS), and others, excellent text which addresses most of the aspects of P5 cide residue analysis is that of Moye published in 1981 (3 r Recent advances in the analysis ofpesticide residues mcl1 increased use ofLC, attempted inclusion ofpolar comP0^ ^ in multiresidue schemes, greater emphasis on analyst metabolites and conjugates, development and use of Gesystems, and methods development for a relatively new c , aMhor expresses J^AC.andthe editc itfcti^Per and for grant - style of its presei HARTOLDMON0030334 BOWMAN: J. ASSOC. OFF. ANAL. CHEM. (VOL. 67, NO. 2, 1984) oth the electrolytic con. tectors are useful for jsticides such as carbj. any of these compounds amative means of analy. 'S of the state-of-the-an owman in 1975 (37-39) alytical chemistry of the of methods, sampling ! desired biological con. hamate analysis, which asses, H. W. Dorougfc pects of carbamate res<e referred to as laboraent on to explain that J the method continued could not make it wort, tarily to the omissionof which, on the surface, malytical chemists have. , and its continued presirticipation in the intertse of the extensive cob which are required for re no "laboratory-spehe adoption of official ssity, lags the state-afheld to a minimum by rocess. 39), the editor emphfc_. ur attention (41). First, .tal samples cannot behey are extracted fromdent extraction of suck ; with its importance.iques have progressed olar solvents, through olarity, to exhaustive s via reflux or Soxhlet incorporated or weatfhiques improved. Howbeled- pesticides haw ; residual radioactivity of the most rigorous Id be made to develop s; the nature and tow sidues should also be cation of pesticide its' t history is often made: edure. It is imperadw or rejected) by seven! s reported in the P t failed to perfonh'^ confirmatory tests a variety of detect0? TLC, p-values, ^ 2), GC or LC ins^ (MS), and others-^ f the aspects of Pff ublished in 1981Q >' iticide residues ind m ofpolar compo?0 jhasis on analys'5/" :nt and use of - ... a relatively netf {pesticides, the synthetic pyrethroids (44). Capillary GC is . References . 'also becoming widely accepted in residue analysis because fthe high quality columns now available which yield a high level of resolution and longevity not previously attainable. An example of the highly .sophisticated methods now being (1) Lane, H. U. (Ed.) (3983) The WorldAlmanac & Book ofFacts. Newspaper Enterprise Association, Inc., New York, NY (2) Shepard, H. H. (1951) The Chemistry andAction oflnsecticides, McGraw-Hill Book Co., Inc., New York, NY (3) Handbookfor AOAC Members (1982) 5th Ed., Association of developed is the isomer-specific determination of 2,3,7,8leuachloro-p-dioxin (2,3,7,8-TCDD) by capillary GC/atmospbericpressure negative chemical ionization/MS (45). It should 5e noted that 22 TCDD isomers are possible and many other chemicals such as DDT, DDE, PCBs, toxaphene, benzyl Official Analytical Chemists, Arlington,''/A (4) Coquillett, D. W. (1886) "Production and Manufacture of Buhacb," U. S. Dept, of Agric. Special Report, Washington, DC . ' (5) Riiey, C. V. (1886) "Entomology Notes.of the Year," U. S. Dept of Agric. Special Report, Washington, DC phenyl ethers, and chlorinated methoxybiphenyls have been hnown to interfere in previous methods; yet in this procedure ihe 2,3,7,8-TCDD can be specifically determined.in tissue at the low parts-per-trillion level. On the other hand, the avail (6) Wiley, H. W. (Ed.) (1899) "Proceedings of the 15th Annual Convention of the AOAC," U. S. Dept of Agric. Bulletin, No. 56, Washington, DC (7) Wiley, H. W. (Ed.) (1900) `^Proceedings of the 16th Annual Convention ofthe AOAC," U. S. Dept ofAgric-. Bulletin, Wash- ability of methodology to determine such infinitesimal levels ington, DC . ' of residues imposes an almost insurmountable task on toxi cologists, i.e., the task to determine their toxicological sig nificance to humans and the environment. An excellent review ofgovernmental regulations pertaining (8) Schechter, M. S., Soloway, S. B., Hayes, R. A., & Haller, H. L. (1945) bid. Eng., Chem. Anal. Ed. 17, 704-709 (9) Averell, P. R., & Norris, M. V. (1948) Anal. Chem. 20, 753 ' 756 ' (10) Giang, P. A., & Hall, S. A. (1951) Anal. Chem. 23, 1830-1834 In pesticides and their residues was presented by Leng in (11) Tswett M. (1906) Ber. deut. botan. Ges. 24,316,384 ' 1981 (46). Pesticide Assessment Guidelines revised in 1982 (12) Purnell, H. (1962) Gas Chromatography, John Wiley and Sons, are available at moderate cost through the Environmental . Inc., New York, NY (13) Brunschwig, H. (1512) Liber de arte distfllandi ' Protection Agency, Washington, DC. Extensive research is (14) Bittel, A. (1957) Thesis, University of Tubingen now required forpesticides before consideration for registra (15) Bayer,E. (1961) Gas Chromatography, ElsevierPublishing Co., tion; therefore, it is anticipated that only effective and safe materials will gain approval in the future. The members and officials of AOAC can take great pride in the accomplishments of the Association during the past New York, NY ' (16) The Holy Bible, King James Version, Exodus 15:22-25 ' (17) . Martin, A. J.P., & Synge, R. L. M. (1941) Biochem. J. 35,1358 (18) Consden, R., Gordon, A. H., & Martin, A. J. P. (1944)Biochem. J. 38, 224 century. Many ofthe significant accomplishments in pesticide (19) Metcalf, R. L., & March, R..B. (1953) Science 117,527-528 analysis previously cited were first reported as meetings of the AOAC and/or in the Journal. Similar accomplishments. were simultaneously being made in many other areas of the analytical sciences. The Official Methods ofAnalysis ofthe (20) James, A. T., & Martin, A. J. P. (1952) Biochem. J. SO, 679 (21) Coulson, D. M., Cavanagh, L. A., De Vries, J. E., & Walther, B. (I960) 7. Agric. Food Chem, 8, 399 '. (22) Gunther, F. A., & Blinn, R. C. (1955) Analysis oflnsecticides andAcaricides, Interscience-Publishers, Inc., New York, NY AOAC will continue to provide a source of tried and proven' methods recognized by government, industry, and the courts. Continued support of the Association by its members and sustaining members, and an even more active participation in the laboratory collaborative process, will ensure the avail (23) Lovelock, J. E., & Lipsky, S. R. (1960)7. Am. Chem. Soc. 82, 431 . (24) Goodwin, E. S., Goulden.R., &. Reynolds, J. G. (1961) Analyst 86,697-709 ' (25) Watts, J. O., & Klein, A. K. (1962) J. Assoc.- Off. Agric. Chem. 45, 102-108 ability of reliable and accepted methods for all of the analyt ical sciences in the future. (26) Beroza, M., Hill, K. R., & Norris, K. H. (1968) Anal. Chem. 40,1611 (27) Beroza, M., & Bowman, M. C..(1965) J. Assoc. Off. Agric. Chem. 48, 358-370 .' Epilog: A Time Capsule for 2084 (28) Bowman, M. C., & Beroza, M. (1965) J. Assoc. Off. Agric. Chem. 48, 943-952 Wth faith that humankind will somehow gain the wisdom (29) Bowman,, M. C., & Beroza, M. (1966) Anal. Chem. 38, 1427 1428 to uye and work together in peace to allow our civilization to' tuwive and develop, the author of this centennial paper and ,J. memhers of AOAC (1984) send greetings and congratu- (30) Giuflnda, L. (1965) J. Assoc. Off. Agric. Chem. 47, 193 ` (31) Brody, S. A., & Chaney, J. E. (1960) J. Gas Chromatogr. 4, 42-46 (32) Bowman, M. C., & Beroza, M. (1968) Anal. Chem. 40, 1448 mem'3ers f AOAC in their bicentennial year put CUrrent raP1i development of electronics, com er science, communication and information systems, and loev6"^6 technolo8y 'n general, makes it impossible for us will .en.TMa8ine what the state-of-the-art in pesticide science 1452 .. (33) Coujson, D. M, (1965) J. Gas Chromatogr. 3, 134 (34) Patchett, G. G. (1970)7. Chromatogr. Sci. 8, 155-158 (35) Hall, R. c. (1974)7. Chromatogr. Sci. 12, 152 (36) Moye, H. A. (Ed.) (1981) Analysis ofPesticide Residues, John Wiley & Sons, New York, NY, p. 291 willb 6,*centUry frm now- Undoubtedly, your technology V S0P^*st'cated compared with ours. We sincerely mQsl atyou have achieved a high quality of life, and that kidts TM Prklenls related to the analysis and use of pess ad all biologically active substances are solved. (37) Bowman, M. C. (Ed.) (1975) J. Chromatogr. Sci. 13, 201-252 (38) Bowman, M. C. (Ed.) (1975) 7. Chromatogr. Sci. 13, 255-300 (39) Bowman, M. G. (Ed.) (1975)7. Chromatogr, Sci. 13, 301-336 (40) Dorough, H. W., & Thorstenson, J. H. (1975). J. Chromatogr. Sci. 13, 212-224 (41) Bowman, M. C. (1975) 7. Chromatogr. Sci. 13, 255 (42) Nash. R. G., & BeaJl, M. L. (1970) 7. Assoc. Off. Anal. Chem. S3,1058 . (43) Wheller, W. B., Thompson, N. P., Edelstein, R. L., Litlell, R. Acknowledgment The = expresses his appreciation to the Editorial Board this paD ' ad editorial staff, for the invitation to prepare in ih, *r.anci for granting the author a wide editorial latitude 8tyle f its presentation. C., & Krause,.R. J. (1979) Abstracts ofthe 93rd Annual Meeting- of AOAC, No. 97 (44) . Sherma, J,, & Zweig, G. (1981) Anal. Chem. S3, 77R-88R (45) Mitchum, R. K., Korfmacher, W. A., & Moler, G. F. (1982) Anal. Chem. 54,719-722 . .' (46) Leng, M. L. (198J) Analysis ofPesticide Residues (Moye, H. A., Ed.) Chapter 10, pp. 395-448, John Wiley & Sons, New York, NY HARTOLDMON0030335