Pesticide Analytical Methodology - ACS Publications - American

11 New Technology for Pesticide Residue Cleanup Procedures

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on December 4, 2015 | http://pubs.acs.org Publication Date: October 30, 1980 | doi: 10.1021/bk-1980-0136.ch011

M. E. GETZ and K. R. HILL Analytical Chemistry Laboratory, Agricultural Environmental Quality Institute, Agricultural Research, Science and Education Administration, U.S. Department of Agriculture, Beltsville, MD 20705 Pesticide residue analysis are conducted for three main purposes: [1] Agriculturists and entomologists are interested in how much residual pesticide is needed to control a pest problem. [2] Regulatory agencies and monitoring stations screen for environmental residues and enforce tolerance regulations. [3] Academic researchers and toxicologists are concerned with metabolites and degradated products. Widely used techniques are: GLC, HPLC, and TLC for general identification and quantitation, with mass spectrometry and infrared spectroscopy for specific identification. Before any of these analyses can be performed, the residue has to be extracted from the containing matrix and isolated in a pure enough state for the particular analytical method. This isolation procedure is called cleanup. As this paper deals primarily with cleanup, we shall assume that the solvent or solvents used for extraction are in general use and that they quantitatively extract the residues. Residues and extractives from different environmental matrices exhibit similar physical and chemical properties and can be classified as lipophilic, hydrophilic, or amphophilic (exhibiting a dual nature). The Food and Drug A d m i n i s t r a t i o n [FDA] P e s t i c i d e A n a l y t i c a l Methods Manual Q J and the Environmental P r o t e c t i o n Agency [EPA] Manual f o r Environmental A n a l y s i s (2) d e s c r i b e procedures that have been used f o r many years. Two of the commonly a p p l i e d techniques a r e l i q u i d - l i q u i d p a r t i t i o n i n g and column a d s o r p t i o n chromatography. These approaches a r e used to i s o l a t e l i p o h i l i c and moderately p o l a r r e s i d u e s f o r primary i d e n t i f i c a t i o n and q u a n t i t a t i o n with GLC. An e v a l u a t i o n of the number of p e s t i c i d e residues that were s a t i s f a c t o r i l y analyzed by t h i s approach was published by McMahon and Burke (3). When one looks a t the data i t can be seen that the h i g h l y p o l a r and water s o l u b l e residues do not f i t i n t o the a n a l y t i c a l scheme very w e l l . In an attempt to r e c t i f y t h i s problem, FDA i s modifying the m u l t i r e s i d u e method

This chapter not subject to U.S. copyright. Published 1980 American Chemical Society In Pesticide Analytical Methodology; Harvey, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1980.

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f o r each i n d i v i d u a l compound that does not adapt to the general procedure. These e x t r a methods have become q u i t e numerous. Our l a b o r a t o r y i s developing two approaches f o r m u l t i r e s i d u e determinations i n an attempt to make the analyses encompass a l a r g e r v a r i e t y of r e s i d u e s , One i s q u a n t i t a t i v e TLC by r e f l e c t i v e scanning ( 4 ) , and the other i s an automated continuous flow system that u t i l i z e s l i q u i d - s o l i d a d s o r p t i o n chromatography coupled w i t h s e l e c t i v e detectors ( J 5 ) (6) . Microcolumn

Cleanup

This approach u t i l i z e s microcolumns of adsorbents to cleanup samples of 10g or l e s s . Various l e n g t h g l a s s columns of 0.5 to 1.0 cm ID can be used. They should have l u e r t i p s and can be obtained with caps to allow low pressure to be a p p l i e d or solvent to be pumped through. F i g u r e 1. Hypodermic needles were used f o r keeping the flow r a t e u n i form. The columns were f i t t e d with 1 1/2" 25 guage needles when the eluant was c o l l e c t e d f o r c o n c e n t r a t i o n , and 1 1/2" 29 guage needles when the eluant was spotted d i r e c t l y onto the t h i n l a y e r plates. The adsorbents evaluated were: alumina [Woelm, n e u t r a l , 105°C f o r 1 h r . ] ; F l o r i s i l R [130°C a c t i v a t i o n ] ; and c h a r c o a l [Darco G-60, 12 χ 20, or Nuchar +30]. When d i r e c t s p o t t i n g onto a TLC p l a t e was used, the columns were packed with 0.5g i n o r g a n i c adsorbent or 0.25g c h a r c o a l between g l a s s wool p l u g s . The adsorbent was compacted by gentle s u c t i o n , and 4 ml of e l u t i n g s o l v e n t was used. A sample s i z e no greater than 2g should be used. I f a l a r g e r s i z e sample i s to be cleaned-up f o r c o l l e c t i o n , the sample weight i s used as a f a c t o r f o r determining the amount of adsorbent necessary, i . e . , 10g sample, (0.5 χ 10) = 5g adsor bent. The e l u t i n g volume i s determined by adding 0.5 to the weight f a c t o r , i . e . , 10g sample (4 χ 10.5) = 42 ml e l u t i n g s o l vent necessary f o r q u a n t i t a t i v e recovery. When d i r e c t s p o t t i n g onto a t h i n l a y e r p l a t e i s used, an automatic s p o t t e r i s necessary £7}. I t u t i l i z e s s i x tubes which t r a n s f e r the e l u t i n g s o l v e n t i n a dropwise manner to the o r i g i n . The s i z e of the spot i s c o n t r o l l e d by the flow of an i n e r t gas from a m a n i f o l d . Three standards and three unknowns are spotted onto a 20 χ 20 cm p l a t e . When the sample i s t r a n s f e r r e d to the cleanup column, i t should be d i s s o l v e d i n the same solvent used f o r e l u t i o n or one of l e s s e r p o l a r i t y . The volume should be no greater than 1 ml. If necessary l a r g e r s i z e samples can be t r a n s f e r r e d i n volumes up to 2 ml. The sample i s p i p e t t e d onto the g l a s s wood p l u g i n a dropwise manner and allowed to soak i n . The s i d e s are then r i n s e d down with 0.5 ml of e l u t i n g s o l v e n t and allowed to s i n k i n . The column i s then e l u t e d with the determined volume of s o l v e n t .

In Pesticide Analytical Methodology; Harvey, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1980.

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When the eluants are c o l l e c t e d , they a r e concentrated and can be analyzed by GLC, HPLC or TLC. For q u a n t i t a t i o n of the TLC scan, the areas of the curves of the standards are p l o t t e d versus c o n c e n t r a t i o n and then the unknown concentrations are determined from t h i s standard curve.


TLC R e s u l t s Organothiophosphates recovered from 0.5g alumina or 0.5g F l o r i s i l R when e l u t e d with 4 ml 20% e t h y l acetate i n 2,2,4trimethylpentane. Pesticide S e n s i t i v i t y ng/g Detection TCQ Azinphosmethyl 100 Azinphosmethyl 0-analog 100 Azinphosethyl 100 Azinphosethyl 0-analog 100 Imidan 100 Malathion 100 Malaoxon 200 Phorate 100 Phorate s u l f o n e 200 Phorate t h i o l 100 Disulfoton 100 Disulfoton sulfone 200 Disulfoton t h i o l 100 Dicapthon 200 Zinophos 200 Coumaphos 200 Methyl p a r a t h i o n 200 Ethyl parathion 200 Zytron 100 Diazinon 200 Carbamates recovered from 0.5g alumina when e l u t e d with 4 ml 20% e t h y l a c e t a t e i n 2,2,4-trimethylpentane. Pesticide Detection S e n s i t i v i t y ng/g Carbaryl TCQ 100 Aldicarb 100 Carbofuran 100 3-Hydroxy carbofuran 100 3-Keto carbofuran 200 Mesurol 100 Landrin 100 Organophosphates q u a n t i t a t i v e l y e l u t e d from 0.25g c h a r c o a l with 4 ml acetone. Pesticide S e n s i t i v i t y ng/g Detection Dimethoate 100 TCQ Malathion 100 Malaoxon 200 "



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Phorate Phorate s u l f o x i d e Phorate s u l f o n e Phorate t h i o l Phorate t h i o l s u l f o x i d e Phorate t h i o l s u l f o n e Disulfoton Disulfoton sulfoxide Disulfoton sulfone Disulfoton thiol Disulfoton t h i o l sulfoxide D i s u l f o t o n t h i o l sulfone Diazinon Crufornate Dicrotophos Dichlorvos Mevinphos Dimethoate 0-analog Trichlorfon Bomyl Crotoxyphos Naled Phosphamidon

Residue

100 200 200 100 200 200 100 200 200 100 200 200 200 100 100 100 100 200 100 100 100 100 100

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TCQ II II It tt II It It tl II tt It tl NBP II It 11 TCQ NBP tt tt tl tt

The organophosphates c o n t a i n i n g s u l f u r were detected w i t h TCQ reagent under a c i d c o n d i t i o n s ( 8 ) . The organophosphates without s u l f u r were detected with nitrobenzylpyridine (9). The carbamates were detected with TCQ under a l k a l i n e con ditions. Recoveries ranged from 75 t o 105%. Each a n a l y s t should determine the optimum e l u t i o n volumes f o r q u a n t i t a t i v e recovery under t h e i r l a b o r a t o r y c o n d i t i o n s . A l l new adsorbents or batches should be checked f o r recovery. the

Continuous Flow

Cleanup

A f i r s t attempt a t t h i s approach was made by adapting the g r a d i e n t e l u t i o n system o f Bowman and Beroza (10) to a c o n t i n uous flow apparatus. H i l l and Jones (5j m o d i f i e d a Pye t r a v e l ing wire d e t e c t o r by s u b s t i t u t i n g a flame photometric d e t e c t o r f o r the c o n v e n t i o n a l flame i o n i z a t i o n one so that i t would be s e l e c t i v e f o r s u l f u r and phosphorus c o n t a i n i n g p e s t i c i d e s . This d e t e c t o r was used f o r m o n i t o r i n g the cleanup e f f i c i e n c y and r e s o l v i n g powers of d i f f e r e n t adsorbents. F i g u r e 2 i s a sche matic diagram of the columns and apparatus used f o r t h i s i n i t i a l study. A g l a s s column 6.3 mm ID χ 24 cm was packed w i t h C o r a s i l I I g l a s s beads. Standard s o l u t i o n s of malathion i n c o n c e n t r a t i o n ranges of 0.1 to 1.0 yg/ml were eleuted from the column with


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Figure 3.



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methylene c h l o r i d e + 2-propanol (80 + 20) with a flow r a t e of 4 ml/min. F i g u r e 3 shows the l i n e a r response obtained. One hundred grams of s t o r e bought s t r i n g beans e x t r a c t e d with methylene c h l o r i d e , were concentrated to 10 ml, and 0.5 ml e q u i v a l e n t to 5g of beans was p l a c e d on the g l a s s bead column and e l u t e d with methylene-chloride+2-propanol s o l u t i o n . This e x t r a c t showed a peak corresponding to 1.5 ng of malathion. When the same e x t r a c t was f o r t i f i e d with a 5 ng e q u i v a l e n t of malathion the r e s u l t i n g response was 6.5 ng malathion. Figure 4 shows the r e s u l t s of these comparisons. A second column was packed with 5g of s i l i c a g e l (Baker 3405). A standard s o l u t i o n of phorate and i t s f i v e m e t a b o l i t e s was p l a c e d on the column and s e q u e n t i a l l y e l u t e d w i t h benzene, 2.5% acetone i n benzene, 10% acetone, and 100% acetone. Figure 5 shows the r e s u l t s obtained. Two hundred grams of B e l t s v i l l e sandy loam were f o r t i f i e d with the i n s e c t i c i d e f e n s u l f o t h i o n and i t s three m e t a b o l i t e s . The i n s e c t i c i d e s were e x t r a c t e d and 0.5 ml of e x t r a c t e q u i v a l e n t to 10g of sample was placed on the column and e l u t e d with the above stepwise g r a d i e n t . The r e s u l t s a r e represented by F i g u r e 6. Two hundred grams of a l f a l f a from a f i e l d t r e a t e d with oxamyl were e x t r a c t e d and d e c o l o r i z e d with c h a r c o a l . A 10g a l i q u o t was placed on the column and e l u t e d with the acetonebenzene g r a d i e n t . The r e s u l t s are shown i n F i g u r e 7. A p p l i c a t i o n of Macroporous S i l i c a

Gels

The Merck Company produces a s e r i e s of s i l i c a g e l s c a l l e d F r a c t o s i l which come i n pore s i z e s from 200 to 25,000 nm. Conv e n t i o n a l s i l i c a g e l used f o r a d s o r p t i o n columns u s u a l l y have pore s i z e s of 40 to 80 nm. These F r a c t o s i l g e l s can be used f o r g e l permeation, a d s o r p t i o n and p a r t i t i o n . The e l e c t r o n microscope scan of F r a c t o s i l 200 compared with conventional s i l i c a g e l appears to be i n the shape of uniform b r e a k f a s t food f l a k e s , Figure 8. The adsorbent i s very r i g i d and can be packed dry. Although the s u r f a c e area i s not v e r y g r e a t , the g e l appears to separate molecules according to p o l a r i t y (12). Hexane with i n c r e a s i n g strengths of acetone can separate many p e s t i c i d e s of v a r y i n g p o l a r i t i e s . Hundreds of food ext r a c t i v e s were run through one column before i t s s e p a r a t i o n e f f e c t i v e n e s s was impaired. F r a c t o s i l 200 i s completely r e cyclable. I t was regenerated by b o i l i n g with 10% HC1, washing and drying a t 110°C. An a d j u s t a b l e g l a s s column of 9mm ID, packed with 5g of F r a c t o s i l 200 was connected to a Spectra Physics pump connected to s o l v e n t r e s e r v o i r s with a s i x way r o t a r y switch. The sample was i n j e c t e d onto the column with a r o t a r y loop sampler. The e f f l u e n t from the column was c o l l e c t e d with an Isco f r a c t i o n c o l l e c t o r s e t so that 10 ml of e l u a t e was c o l l e c t e d f o r each


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STR- BEAN EXTRACT 5 GMS+ 5 N G S 7 0 S Q CM

120

5 4 SQ CM


98 PEAK HEIGHT STR* BEAN EXTRACT 5 GMS 2 0 SQ CM 1-6 SQ CM

IN (mm)

32 0 9 SQ CM

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300

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Figure 5.


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PYROLYSIS OVEN TEMPERATURE k460*O|*-520 C »fi 660 C e

CHROMATOGRAM OF STANDARD SOLUTION OF DASANIT AND ITS METABOLITES

DASANIT SULFONE

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ELUTION TIME-MINUTES -COLUMN ELUANT-BENZ£NEf>2.5% A C E T 0 N E * | « - I 0 % ACETONE-

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PYROLYSIS OVEN T E M P E R A T U R E -460 C*H rf520#c * 660 C CHROMATOGRAM OF EXTRACT OF 10 GRAMS OF SOIL FORTIFIED WITH DASANIT AND ITS METABOLITES e

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ELUTION TIME - MINUTES -COLUMN E L U A N T - Β Ε Ν Ζ Ε Ν Ε ψ - 2 . 5 % ACETONE^ION ACETONE-

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Figure 6.



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OF O X A M Y L

IN

ALFALFA

ACETONEEXTRACT OF TREATED ALFALFA 0.5 ml • · 10 gram*

'40

H 1

BENZENE COLUMN

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1

Figure 7.


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2.5 minutes. Each of the s i x solvent r e s e r v o i r s contained 100% hexane, 10% acetone i n hexane, 20% acetone i n hexane, 40% ace tone i n hexane, 100% acetone and 100% methanol. When the sample was i n j e c t e d onto the column, the pump was s t a r t e d and the f i r s t 10 ml e l u a t e c o l l e c t e d . The pump was then stopped and the solvent v a l v e turned t o the next g r a d i e n t . This procedure was repeated u n t i l the 100% acetone e l u a t e was c o l l e c t e d . A f t e r a second 10 ml e l u a t e of acetone was taken, the column was ready f o r r e c y c l i n g . The column was r e c y c l e d by pumping through s u c c e s s i v e volumes of 25 ml methanol, 50 ml acetone, and 25 ml hexane. F o r t i f i c a t i o n Studies The f o l l o w i n g matrices were f o r t i f i e d f o r the e v a l u a t i o n s t u d i e s of F r a c t o s i l 200: tomatoes, c a r r o t s , green apples, animal f a t , m i l k and greenhouse s o i l . Endosulfans A, Β and the s u l f a t e were q u a n t i t a t i v e l y r e covered at c o n c e n t r a t i o n l e v e l s of 0.2 and 2.0 ppm. A l i q u o t s r e p r e s e n t i n g 2g of the o r i g i n a l sample were i n j e c t e d onto columns f o r clean-up. The cleaned-up e l u a t e s were analyzed by GLC and e l e c t r o n capture d e t e c t i o n to see i f any i n t e r f e r e n c e s or a r t i f a c t s would show up under the c o n d i t i o n s necessary to measure 0.2 ppm of endosulfan and i t s m e t a b o l i t e . Colored e l u a t e s were observed i n the 10% f r a c t i o n s from tomatoes, c a r r o t s , green apples, and green house s o i l . Another pigment, seen as a t i g h t band on top of the column, was not e l u t e d u n t i l methanol passed through during the f i r s t stage of r e c y c l i n g . No c o l o r i n any f r a c t i o n was observed from f a t or m i l k samples. However, when the e l u a t e s were evaporated down to dryness a volume of o i l y m a t e r i a l appeared i n the bottom of the tubes c o n t a i n i n g the 10% e l u a t e . When GLC and e l e c t r o n capture d e t e c t i o n were used with the PAM GC columns Q J f o r organoc h l o r i n e s , except f o r the 10% f r a c t i o n from the animal f a t , no a r t i f a c t s or base l i n e e f f e c t s were noted. F i g u r e 9 i l l u s t r a t e s a t y p i c a l chromatogram obtained from a 10 μ ΐ i n j e c t i o n of a 10 ml a l i q u o t concentrated to 1 ml. F i g u r e 10 shows the r i s i n g base l i n e and peak obtained from the 10% acetone e l u a t e of the animal f a t e x t r a c t . A l l samples of beef f a t e x h i b i t e d t h i s peak. The same m a t r i c e s as d e s c r i b e d above were f o r t i f i e d with phorate and i t s m e t a b o l i t e s , and t h i o l demeton and i t s metab olites. % p e s t i c i d e i n each e l u a t e . 10% 20% Pesticide Hexane Acetone Acetone Endosulfan A 40% 60% Endosulfan Β Endosulfan SO4

40% Acetone

Acetone

96% 92%


Acetone

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% p e s t i c i d e i n each e l u a t e .


10%

Pesticide Hexane Phorate 80% Phoratoxon Phoratoxon SO Phoratoxon SO2 Demeton t h i o l Demeton t h i o l SO Demeton t h i o l S02

Acetone

(Continued) 40% Acetone Acetone

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20%

Acetone

Acetone

10% 10%

90% 90%

10% 10%

90% 90%

20%

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90%

A g e l permeation column used i n c o n j u n c t i o n w i t h an Autoprep 1001 was removed and replaced w i t h a 1 cm ID a d j u s t a b l e g l a s s column packed with a 15 cm length of F r a c t o s i l 200. A system f o r p r o v i d i n g step gradient s o l v e n t programming was installed. Step gradient f o r t e s t i n g F r a c t o s i l 200 i n c o n j u n c t i o n w i t h the Autoprep 1001. _ _ Solvent Volume, ml Methanol 25 Acetone 50 50 Hexane 10 5% acetone/hexane 10 10% acetone/hexane 10 20% acetone/hexane 20 Acetone Rapid c y c l e Methanol The use of the F r a c t o s i l 200 produced a f l a t almost n o i s e f r e e b a s e l i n e w i t h the flame photometric d e t e c t o r . System t e s t i n g was begun by e s t a b l i s h i n g response and r e t e n t i o n times f o r a d j u s t i n g the s o l v e n t Program. This was accomplished by i n j e c t i n g samples of phorate s u l f o x i d e and chlorpyrifos. Chromatograms w i t h narrow w e l l shaped peaks as shown i n F i g u r e 11 were obtained. Two d i f f e r e n t s o l v e n t programs were used:

Solvent Hexane 0.2% acetone/hexane 0.3% acetone/hexane 0.6% acetone/hexane 0.9% acetone/hexane 1.0% acetone/hexane 100% acetone Methanol Acetone Hexane

Program A Time (min.) 3 2 2 2 2 2 20 6 12 6

Solvent Hexane 10% acetone 20% acetone 50% acetone 75% acetone 100% acetone Methanol Acetone Hexane

Program Β Time (min.) 3 2 2 2 2 20 8 16 10



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CHLORPYRIFOS 228 ug i n j t c t « c * d

MIN.

MIN. Figure 11.


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Data A c q u i s i t i o n and A n a l y s i s System At the i n i t i a t i o n of t h i s study, a computer based data s y s tem designed to p l o t data p o i n t s versus time and determine peak areas was made o p e r a t i o n a l . The f o l l o w i n g chromatograms were obtained with the F r a c t o s i l 200 s i l i c a g e l and the Pye moving wire d e t e c t o r as shown i n Figure 2. They were p l o t t e d by the computer. The axes are the response i n m i l l i v o l t s versus time i n seconds. When the computer r e c o n s t r u c t e d the chromatogram, the Y-axis could be magnified from 0 to 520 m i l l i v o l t s . Chromatogram 1 shows an e x t r a c t r e p r e s e n t i n g 5.6g of B e l t s v i l l e sandy loam s o i l , e l u t e d with program Β and detected by the s u l f u r mode. The e l u t i o n flow r a t e was 2 ml/min. Chromatogram 2 represents 6.0g of the same s o i l with s i m i l a r e l u t i o n and flow r a t e . D e t e c t i o n was by the phosphorus mode. Chromatogram 3 i s the response of l.Og of s o i l f o r t i f i e d with 65.4 y g a l d i c a r b . Small responses can be seen at 2 and 3. Chromatogram 4 i s a repeat of 3 but the computer has mag n i f i e d the Y-axis to show that peaks 2 and 3 are r e a l and not due to n o i s e . Chromatogram 5 i s one where 0.56g of f a t e x t r a c t e d w i t h e t h y l acetate has been i n j e c t e d onto the column and e l u t e d w i t h program Β at 2.0 ml/min. with phosphorus d e t e c t i o n . Chromatogram 6 i s 0.30g of f a t that was f o r t i f i e d w i t h 80.6 yg a l d i c a r b s u l f o x i d e e l u t e d with program Β and detected by the s u l f u r mode. The p o l a r i t y of the a l d i c a r b s u l f o x i d e has allowed i t to be separated from i n t e r f e r e n c e s . Chromatogram 7 shows what happens when the oven tube gets d i r t y . T h i s can happen a f t e r many f a t samples have been analyzed. Experience has shown that the F r a c t o s i l 200 s i l i c a g e l i s not v e r y e f f e c t i v e f o r removing f a t i n t e r f e r e n c e s when l i p o p h i l i c compounds are to be analyzed. However, i t ' s v e r y e f f i c i e n t when p o l a r compounds are to be i s o l a t e d . A new s y n t h e t i c carbanaceous r e s i n (Rohm and Haas) (12) has been found to be very e f f e c t i v e f o r h o l d i n g up non p o l a r i n t e r ferences from f a t s and o i l s while a l l o w i n g many l i p o p h i l i c p e s t i c i d e s to be q u a n t i t a t i v e l y e l u t e d . This was adapted to automated e l u t i o n and was found out to a l s o be r e c y c l a b l e . A c e t o n i t r i l e i s used f o r e l u t i n g the p e s t i c i d e s and chloroform i s used f o r r e c y c l i n g the column by d i s p l a c i n g the adsorbed i n t e r f erences. The p r e l i m i n a r y data has shown that the two new adsorbents are a major breakthrough f o r automating the cleanup step, and a l l o w i n g a wider s p e c t r a of p e s t i c i d e s to be analyzed.


11.

GETZ

Pesticide Residue

A N D HILL

225

Cleanup

5XC ' 4 50 —f

4-00

3.66. SOIL

H

S- FILTER


>3·50

(0 3.00 '

I w

250 —I

uj

2.00 —I .50

3O0

3ÔÔ I2ÔÔ

600 TIME ( S E C )

ÏÎÔO

Chromatogram 1.

5.00

-ι

450 -η &0G. SOIL 4.00

"I Ρ-FIL Τ E R

^ >

3 50-

3O0* Ο α.

2.00-t

1.50

Ο

300

Too 600 900 1200 TIME (SBC)

ιίοο

Chromatogram 2.


226

PESTICIDE

ANALYTICAL

METHODOLOGY


LOG SOIL Plus 65.4ng ALDICARB S-FILTER

ioo tfoo Mbo SET

300

TIME ( S C O Chromatogram 3.

ALDCARB

EXPANDED Y-AXIS

300

*O0

00 (9K)

Too TIME

-

1900

I

Chromatogram 4.


11.

GETZ

Pesticide

A N D HILL

4.90.

Residue

a N i

FAT P-FILTER

4.004


227

Cleanup

3.50

ο a: 3-00·

1

300

C

ι 600

I 1 900 1200 TIME (SEC)

ι 1500

1 1 1800 2100

Chromatogram 5.

0 30 G FAT plus 8 0 6 · g A LOÏC ARB SO (Ο S-RLTER ~ 350" ft 3.00jg 2.502.00-

—ι 0

300

1 1 1 600 900 1200 TIME (SEC)

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Chromatogram 6.



228

PESTICIDE

ANALYTICAL

METHODOLOGY

Chromatogram 7.


11.

GETZ

A N D HILL

Pesticide Residue

Cleanup

229

Acknowledgments We wish t o thank Glenn Hanes of t h i s l a b o r a t o r y f o r h i s data c o l l e c t i n g and development of a u s e f u l computer program.


References (1) Pesticide Analytical Manual. Vols. I, II, and III. U.S. Department of Health Education and Welfare. Food and Drug Administration. Washington, D.C. (2) Manual for Analytical Quality Control for Pesticides and Related Compounds in Human and Environmental Samples. U.S. Environmental Protection Agency. Health Effects Research Laboratory. Research Triangle Park, North Carolina. (3) McMahon, B., and Burke, J. Α., J. Assoc. Offic. Anal. Chem. 61 640 (1978). (4) Getz, M. E. Methods in Residue Analysis. Vol. IV, pg. 43. Ed. A. S. Tahori., Gordon and Breach, New York, Ν. Y. (1972). (5) Hill, K. R. and Jones, W. M. Adaptation of the Flame Photometric Detector to Liquid Chromatography of Pesticides. 3rd International Conference of Pesticide Chemistry, Helsinki, Finland, July 3-9, 1974. (6) Hill, K. R., J. Chromatogr. Sci. 17, 395 (1979). (7) Getz, M. E . , J. Assoc. Offic. Anal. Chem. 54, 982 (1971). (8) Beroza, M., Hill, K. R., and Norris, Κ. Η., Anal. Chem. 40, 1608 (1968). (9) Getz, M. E. and Wheeler, H. G., J. Assoc. Offic. Anal. Chem. 51, 1101 (1968). (10) Bowman, M. C. and Beroza, M. J., Agr. Food. Chem. 16, 399 (1968). (11) Getz, M. E . , Talanta 22, 395 (1975). (12) Getz, M. E . , Hanes, G. W., and Hill, K. R. Trace Organic Analysis, New Frontier in Analytical Chemistry, pgs. 345-53. NBS Special Publication 519. Eds. Hertz, H. S. and Chesler, S. N. (1979). Chromatograms 1-7 were obtained as part of an interagency agreement (EPA-IAG-D6-0741) with the Chemistry Branch, Pesticide and Toxics Substances Effects Laboratory, Health Effects Labora tory, Office of Research and Development, Environmental Protec tion Agency, Research Triangle Park, North Carolina. The views expressed herein are those of the investigators and do, not necessarily reflect the official viewpoint of the Department of Agriculture or the Environmental Protection Agency. RECEIVED March 6, 1980.


Pesticide Analytical Methodology - ACS Publications - American

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