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Aspects of Analytical Toxicology Related to Analysis of Pesticidal Trace Contaminants: An Overview LAWRENCE FISHBEIN Department of Human and Health Services, Food and Drug Administration, National Center for Toxicological Research, Jefferson, AR 72079 We are a l l becoming increasingly aware of the potential adverse effects induced by trace levels of a spectrum of chemicals (primarily pesticides and industrial chemicals) in the environment. For example, the cause for public health concern over Mirex, Kepone, DBCP, HCB, PCBs, PBBs, nitrosamines and the wide spread use of chemicals contaminated with polychlorinated dibenzo-p-dioxins and dibenzofurans are well documented. This of necessity has placed an increasing focus and pressure on both the analytical chemist and toxicologist. There is a primary need for the analytical chemist to develop and refine techniques relating to the detection, determination and confirmation of trace impurities (often at parts-per-billion or lower), in consumer products, in the workplace and in the environment. Toxicologists are increasingly confronted with an equally difficult array of problems relating to the elaboration of techniques and methodologies that will enable them to detect biological and toxicological events at what is increasingly recognized to be the major exposure problem, continuous low-level exposure at the sub parts-per-million or parts-per-billion level of trace impurites or trace levels of the toxicant per se. In the f o r e f r o n t of chemicals of p o t e n t i a l environmental and human t o x i c o l o g i c a l concern are the p e s t i c i d e s both from the spectrum of agent and t h e i r use patterns as w e l l as p o t e n t i a l degree of population exposure. The l a t t e r includes those i n v o l v e d i n the preparation, formulators, a p p l i c a t o r s , p i c k e r s , processors and f i n a l l y the consumers. The major o b j e c t i v e s of t h i s overview are to h i g h l i g h t s e v e r a l of the newer advances i n the a n a l y s i s of t r a c e i m p u r i t i e s i n and of p e s t i c i d e s per s e . D e t e c t i o n by t h e Thermal E n e r g y A n a l y z e r chemical Detection It i s recognized increasing recognition

(TEA) and E l e c t r o -

t h a t o t h e r newer a r e a s t h a t i n p e s t i c i d e and t r a c e a n a l y s i s

This chapter not subject to U.S. copyright. Published 1981 American Chemical Society

Bandal et al.; The Pesticide Chemist and Modern Toxicology ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

deserve include:

350

THE

PESTICIDE

CHEMIST

A N D

M O D E R N

TOXICOLOGY

J A

P - F o u r i e r Transform NMRM, radioimmunoassay, pulse-polarography and low and room temperature phosphorescence a n a l y s i s . Eight d i s t i n c t steps a r e recognized i n trace organic a n a l y s i s . These are: (a) c o l l e c t i o n , (b) storage, (c) e x t r a c t i o n , (d) c o n c e n t r a t i o n , (e) i s o l a t i o n , ( f ) i d e n t i f i c a t i o n , (g) q u a n t i f i c a t i o n , and (h) c o n f i r m a t i o n . The instrumental f a c i l i t i e s f o r c a r r y i n g out the three b a s i c a c t i v i t i e s of a n a l y t i c a l chemistry are s e p a r a t i o n , i d e n t i f i c a t i o n and measurement a r e shown i n Table 1. We a d d i t i o n a l l y recognize the f a c t that the power of a n a l y t i c a l techniques can be increased by combining s e v e r a l a n a l y t i c a l techniques, or what can be r e f e r r e d to as synergism between methods (1,2). Thus we can combine high d i s c r i m i n a t i n g power i n one technique with a high separating power i n the other. For example, gas c h r o m a t o g r a p h y ' s e x c e l l e n t q u a n t i t a t i o n and r e l a t i v e l y poorer q u a l i t a t i o n can be w e l l matched to the good q u a l i t a t i o n and r e l a t i v e l y poorer q u a n t i t a t i o n of i n f r a r e d or mass spectrometry. Table 2 i l l u s t r a t e s the synergism and the strengths and weaknesses of a n a l y t i c a l techniques which can be achieved between GLC, LC, TLC and MS and F o u r i e r NMR. The v a r i o u s a n a l y t i c a l systems can be ranked i n the order of t h e i r u s e f u l n e s s for trace organic a n a l y s i s . Mass spectrometry provides s u f f i c i e n t s e n s i t i v i t y f o r t r a c e a n a l y s i s and i s e a s i l y i n t e r f a c e d t o a gas chromatograph. I t i s g e n e r a l l y acknowledged that combined GC/MS i s c u r r e n t l y the most powerful and u s e f u l technique f o r the i d e n t i f i c a t i o n of t r a c e l e v e l s of organic compounds. I t can provide q u a l i t a t i v e i n f o r m a t i o n with nanogram q u a n t i t i e s of s i n g l e compounds present i n the sample and i n a d d i t i o n i t provides a mass spectrum of each peak e l u t i n g from the GC. Hence, the GC/MS data can be p l o t t e d i n the form of mass chromatograms as an a d d i t i o n a l i n t e r p r e t i v e a i d ( 3 ) . While gas chromatography i s s t i l l the most widely u t i l i z e d technique i n trace organic a n a l y s i s , i t should be recognized that recent advances i n HPLC have made HPLC comparable to GC i n speed, convenience and e f f i c i e n c y (3-6). LC o r HPLC with detectors such as MS, e l e c t r o c h e m i c a l , UV, and f l u o r e s c e n c e i s hence of i n c r e a s i n g u t i l i t y . Coupled to the various^ d e t e c t o r s , the minimal detectable q u a n t i t i e s f o r L ^ a r e : UV, 10 g; e l e c t r o chemical, 10 g; and f l u o r e s c e n c e , 10 g. Sample s i z e s must be i n the sub-ppm range (4_). The UV detector i s almost u n i v e r s a l f o r organics while the e l e c t r o c h e m i c a l detector i s s e l e c t i v e and the fluorescence detector i s even more s e l e c t i v e (3,4). For example, with f l u o r e s c e n c e spectroscopy i t i s p o s s i b l e to vary both the e x c i t a t i o n wavelength and the wavelength a t which the emission i s observed thus p r o v i d i n g a d d i t i o n a l spectrometric information ( 3 ) . Chemiluminescent Detectors Nitrosamine A n a l y s i s

(Thermal

Energy

Analyzers) i n

It i s w e l l recognized that humans may be exposed to N - n i t r o s o compounds i n a v a r i e t y of ways, v i z . , (1) formation i n the environment with subsequent absorption from a i r , water, food


22.

FiSHBEiN

Pesticidal

Trace

351

Contaminants

TABLE 1 The Three Pillars of Analytical Chemistry (1) Separation

Identification

Dependent on physical properties: Fluorescence, Nmr, Thermal analysis, Ir/Raman, Microscopy Ms and gc-ms, Sedimentation, Uv, UV absorbance, Comparison with properties of a standard Atomic absorption, Nmr

Instrumental separation by discriminating detection: Nmr (by chemical shift dispersion), Selective potentiometry, Ms (by single or multiple ion detection)

Physical Methods;

Physical separation:

Chemical methods:

Phase extraction, Chemical separation, Chromatography (Ictlcgc)

Measurement

Dependent on chemical properties: Functional group analysis, Polarography, Spot tests, Potentiometric titration Elemental analysis, Radiochemistry, Atomic absorption Gc-ms


352

T H E

PESTICIDE

CHEMIST

A N D

M O D E R N

TOXICOLOGY

TABLE 2 Synergism of Analytical Techniques (1) Gc (volatiles only) separation

Le

·

sensitivity

separation

·

·

sensitivity

quantification ·

·

quantification

identification

ο ο

identification

Tic

•· •· •·

separation

·

sensitivity

·

quantification ο

ο ο

identification

ο ο

Mass spectrometry Fourier NMR U

C separation sensitivity

Gc-ms (volatiles only) · separation

ο ο

sensitivity

quantification · identification ·

·

· ·

·

quantification ·

·

identification ·

·

3H separation ο sensitivity

Ms

·

quantification · identification ·

·

separation

ο ο

sensitivity

·

·

quantificationo ο identification · • = Strength

·

o = Weakness


22.

FISHBEIN

Pesticidal

Trace

Contaminants

353

and/or i n d u s t r i a l and consumer products; (2) from the consumption or smoking of tobacco; (3) from n a t u r a l l y o c c u r r i n g compounds (considered to be an exceedingly minor c o n t r i b u t i o n ) and (4) formation i n the human body from precursors ingested s e p a r a t e l y i n food, water or a i r . The l a t t e r category i s acknowledged by many to be of i n c r e a s i n g concern but aspects of the p o t e n t i a l r i s k are as yet to be unambiguously d e f i n e d . The c a r c i n o g e n i c i t y , mutag e n i c i t y , and t e r a t o g e n i c i t y of a broad spectrum of nitrosamines has been i n c r e a s i n g l y and exceedingly w e l l documented (7-11). The o c c u r r e n c e of t h e n i t r o s a m i n e s , whether as d i r e c t emissions of N-nitroso compounds or v i a l o c a l i z e d r e l e a s e of l a r g e amounts of precursor compounds (e.g., secondary amines, n i t r o g e n o x i d e s , n i t r a t e , n i t r i t e s ) , e f f l u e n t d i s c h a r g e s from sewage treatment plants or runoff from f e e d l o t s or croplands t r e a t e d with amine p e s t i c i d e s , ammonium f e r t i l i z e r s or nitrogenous organic m a t e r i a l s , or a c c i d e n t a l products i n food processing and use, tobacco smoke, or v i a the body burden c o n t r i b u t e d by i n v i v o n i t r o s a t i o n r e a c t i o n s , has s p a r k e d e v e r i n c r e a s i n g i n t e n s i v e i n v e s t i g a t i o n s as to the o v e r a l l scope of the p o t e n t i a l sources, mechanism of In v i t r o and rn v i v o formation, body burdens as w e l l as to the need to develop a proper s c i e n t i f i c foundation f o r a human h e a l t h r i s k assessment (7-14). In order to best develop a proper s c i e n t i f i c b a s i s f o r the assessment of human r i s k a s s o c i a t e d with p o t e n t i a l nitrosamine exposure, i t i s of course v i t a l that we possess the r e q u i s i t e s e n s i t i v e and s e l e c t i v e a n a l y t i c a l methodologies p r i m a r i l y f o r the d e t e c t i o n and determination of exceedingly low l e v e l s (ppb-ppt) of nitrosamines, p a r t i c u l a r l y i n environmental samples. A s e n s i t i v e and s e l e c t i v e chemiluminescent d e t e c t o r that has made an a p p r e c i a b l e impact on the a n a l y s i s of nitrosamines i n environmental samples i n the l a s t s e v e r a l years i s the thermal energy analyzer or (TEA) (15-19). T h i s d e t e c t o r u t i l i z e s an i n i t i a l p y r o l y s i s r e a c t i o n that cleaves nitrosamines a t the N-NO bond to produce n i t r i c oxide. Although e a r l i e r instrumentation involved the use of a c a t a l y t i c p y r o l y s i s chamber (15,17,19), i n current instruments, p y r o l y s i s takes place i n a heated quartz tube without a c a t a l y s t (20). The n i t r i c oxide i s then detected by i t s chemiluminescent i o n react with ozone. The sequence of r e a c t i o n s can be depicted i n Figure 1. A schematic of the TEA i s shown i n F i g u r e 2 (17). Samples are introduced i n t o the p y r o l y s i s chamber by d i r e c t i n j e c t i o n or by i n t e r f a c i n g the d e t e c t o r with a gas chromatograph (15,17,21,22) or a l i q u i d chromatograph (22-25). Chemiluminescence d e t e c t o r s possess c o n s i d e r a b l e s e l e c t i v i t y for nitrosamines because the l i g h t emitted from the NO-ozone r e a c t i o n i s i n the near i n f r a r e d r e g i o n , whereas other known chemiluminescent r e a c t i o n s with ozone emit l i g h t i n the v i s i b l e or near UV region (17,20,26,27). An o p t i c a l f i l t e r e l i m i n a t e s response to emissions o c c u r r i n g below 600 nanometers. Selectivity i s a d d i t i o n a l l y provided by a c o l d t r a p between the p y r o l y s i s chamber and the NO-ozone r e a c t i o n chamber which removes a l l but


354

THE

N-N

PESTICIDE

CHEMIST

• N

NO* + 0

• N 0

3

N0 *

• N 0

2

A N D M O D E R N

+ NO*

2

2

*

+

0

2

+ hv

l u m i n e s c e n c e in n e a r

Figure 1.

TOXICOLOGY

infrared

Basis of chemuluminescent detection with a TEA

SAMPLE INLET PHOTOMULTIPLIER TUBE

O P T I C A L ^ " COOLED CHAMBER FILTER (-20°C) ΓΊ PRESSURE LJREGULATOR OZONATOR POWER SUPPLY

o

I CHARCOAL CATALYST VACUUM

2

Analytical Chemistry Figure 2.

Schematic of the TEA (11)


22.

FISHBEIN

Pesticidal

Trace

355

Contaminants

the most v o l a t i l e compounds e l u t i n g from the p y r o l y s i s chamber (20). The TEA analyzer i s s e n s i t i v e to picogram q u a n t i t i e s of N-nitroso compounds (15,16,22-26) with a l i n e a r response extending over f i v e orders of magnitude. W h i l e the c h e m i l u m i n e s c e n c e d e t e c t o r s have c o n s i d e r a b l e s e l e c t i v i t y f o r nitrosamines i t must a l s o be recognized that the p o s s i b i l i t y e x i s t s that any compound that can produce NO during p y r o l y s i s w i l l produce a s i g n a l (20). For example, TEA responses have been observed from organic n i t r i t e s , C - n i t r o and C - n i t r o s o compounds (17,28) and nitramines (29). In the r o u t i n e a n a l y s i s of N-nitroso compounds, p o s s i b l e TEA analyzer responses to compounds other than N-nitroso d e r i v a t i v e s normally do not represent a problem s i n c e the the i d e n t i t y of a compound can be r e a d i l y e s t a b l i s h e d by c o - e l u t i o n with known standards on GC-TEA and/or HPLC-TEA systems ( 3 0 - 3 4 ) . A d d i t i o n a l c o n f i r m a t i o n c o u l d be provided when the sample can be chromatographed on both GC-TEA and HPLC-TEA (30,33). The technique accepted as the most r e l i a b l e f o r the c o n f i r m a t i o n of N-nitrosamines i s based on mass spectrometry (22,35,36). Low-resolution mass spectrometry i s s a t i s f a c t o r y f o r the a n a l y s i s of r e l a t i v e l y simple mixtures and i n those i n s t a n c e s i n w h i c h e x t e n s i v e c l e a n - u p of samples has been p e r f o r m e d . However, complex samples r e q u i r e more s o p h i s t i c a t e d GC and MS procedures (e.g., high resolution-MS). F a r r e l l i et a l (37) described the determination of v o l a t i l e N-nitrosamines as p e s t i c i d e contaminants u t i l i z i n g gas chromatograph-mass fragmentography. Q u a n t i t a t i o n was accomplished by a GC/MS (Finnigan Model 300) equipped with a programmed, m u l t i p l e i o n d e t e c t i o n system used i n the E . I . mode. T r i f l u r a l i n was found to c o n t a i n 34 ppm of d i p r o p y l n i t r o s a m i n e by t h i s technique. Figure 3 shows a mass fragmentogram obtained by a n a l y z i n g a s o l u t i o n of t r i f l u r a l i n where a peak at m/e 130 can be observed with the same r e t e n t i o n time as d i p r o p y l n i t r o s a m i n e (DPN). The presence of DPN i n the t r i f l u r a l i n sample was confirmed t a k i n g a f u l l mass spectrum of the contaminant (Figure 4 ) . K r u l l et a l (30) r e c e n t l y described r a p i d and reliable confirmatory methods f o r the thermal energy determination of N-nitroso compounds at trace l e v e l s . These approaches u t i l i z e minor m o d i f i c a t i o n s i n the normal operation of the a n a l y z e r , GC and HPLC i n t e r f a c e d with the a n a l y z e r , UV i r r a d i a t i o n of the sample and wet chemical procedures. Comparisons were made between t h e s e a n a l y z e r a s s o c i a t e d methods of c o n f i r m a t i o n and o t h e r approaches f o r the determination of N-nitroso compounds at t r a c e levels. Figure 5 i l l u s t r a t e s the a n a l y s i s scheme by K r u l l et a l (30) to d i s t i n g u i s h N-NO compounds from C-NO, 0-NO, N-N0 , C-N0 , and O-NO^ compounds u t i l i z i n g the TEA a n a l y z e r . There i s recognized widespread concern about the p o s s i b i l i t y of both f a l s e p o s i t i v e and f a l s e negative f i n d i n g s at low ppm to low ppb c o n c e n t r a t i o n l e v e l s of the N-nitrosamines generally reported. Such a r t i f a c t s could a r i s e during sample p r e p a r a t i o n , e x t r a c t i o n and/or subsequent chromatographic a n a l y s i s (38). The 2


2

356

THE

PESTICIDE

CHEMIST

A N D M O D E R N

TOXICOLOGY

Trifluralin

m/e 8 4

r"'*W»

m/e 130 m/e 102

m/e 7 4 ΙΙ Ο min

5

0 Analytical Letters

Figure 3.

Mass fragmentogram of trifluralin (31)

43

lOO-r

70

I

CH -CH -CH ^

60+

3

2

2

N-NO

CH -CH -CH '

Φ > ο Φ

MW130

DPN

80 +

3

40 1

2

2

30

20+ 130

30

—ι— 50

70

90

110 m/e

130

150

170 Analytical Letters

Figure 4.

MS of ^-dipropylnitrosamine (31)



Figure 5.

. Loss of TEA · Response

• Loss of TEA · Response

Unsaturated Organics

Most Organics

C-NO O-NO

N-NO C-NO

Loss of TEA Response

UV Irradiation Test

N-NO. C-NO

TEA Response Unchanged

I HOAc Test}

N-NO


HBr/HOAc Test

TEA Signal Unchanged


.TEA Response Unchanged

2

and

Analytical Chemistry

C-NO

lO-NO

N-N02. 0-N02 C-N02

Chemical confirmatory techniques

N-NO. C-NO. O-NO N-NO2. C-NO2. O-NO2

Part 2

Analysis scheme to distinguish N-NO compounds from C-NO, O-NO, C-N0 , O-NO2 compounds using the TEA (30)


Cold Trap Plus Tenax-GC In-Line Trap

Unsaturated Organics N-NO C-NO O-NO N-NO? C-NO2 O-NO2


l-150°C TEA Cold Trap h

Organics. Unsaturated Organics N-NO. C-NO. O-NO N-NO?. C-NO2. O-NO2I

Part 1. TEA analyzer parameters

358

THE

PESTICIDE

CHEMIST

A N D

M O D E R N

TOXICOLOGY

source of n i t r o s a t i n g agent which could be r e s p o n s i b l e f o r a p o s i t i v e a r t i f a c t , has i n c l u d e d n i t r i t e contamination of the sample i t s e l f , open column chromatography on n i t r i t e contaminated packing m a t e r i a l s f o r GC and LC columns, a b s o r p t i o n of n i t r o g e n oxides from ambient a i r , and nitrosamine contaminated d e i o n i z e d water and organic s o l v e n t s . Precautions are a l s o r e q u i r e d to prevent the a c c i d e n t a l d e s t r u c t i o n of N-nitroso compounds which can occur i n s u n l i g h t and even under conventional f l u o r e s c e n t l i g h t i n g s (37). N-nitroso compounds can be destroyed during GC or HPLC. I t i s p o s s i b l e , as i n the case of N-nitroso compounds with f r e e OH groups such as N-nitrosodiethanolamine and N-nitrosamino acids that these compounds may give a sub-molar response by TEA detection. While the u t i l i t y of the thermal energy analyzer f o r the estimation of nitrosamines i n a i r and water has been p r e v i o u s l y demonstrated by Fine and h i s co-workers (15-19,23-26), i t i s particularly r e l e v a n t to c o n s i d e r i t s u t i l i z a t i o n i n the determination of nitrosamines as t r a c e i m p u r i t i e s i n p e s t i c i d e s as w e l l as n i t r o s a t e d pesticides. There are two major r a t h e r d i s t i n c t problem areas that can lead to human exposure i n t h i s area and hence p o t e n t i a l r i s k to c o n s i d e r . One area focuses on the concern that c e r t a i n n i t r o g e n - c o n t a i n i n g p e s t i c i d e s (e.g., carbamates, ureas, t r i a z i n e s , amides, a n i l i d e s ) , as residues i n s o i l , water, p l a n t s , e t c . , may be n i t r o s a t e d by exogenous n i t r i t e or by o t h e r n i t r o s a t i n g a g e n t s , e.g., n i t r o g e n o x i d e s from automobile, t r a c t o r or truck exhausts or other f u e l consumption. The o t h e r a r e a c o n c e r n s the p o s s i b i l i t y t h a t a v a r i e t y of p e s t i c i d e s which are a p p l i e d to s o i l and p l a n t s may contain n i t r o s o compounds as i m p u r i t i e s (39). These i m p u r i t i e s may a r i s e from the three most probable routes of N-nitroso contamination, e.g., (a) formation i n the manufacturing process; (b) formation during storage and (c) contamination of amines used i n the manufacturing process (39-47). I t was i n i t i a l l y reported by Fan et a l i n 1976 that f o u r of seven h e r b i c i d e s p u r c h a s e d i n r e t a i l o u t l e t s had c o n t a i n e d measurable concentrations of nitrosamines as detected with a thermal energy analyzer (43). Three of the h e r b i c i d e s c o n s i s t e d of p o l y c h l o r o b e n z o i c a c i d s formulated as dimethylamine s a l t s and contained dimethylnitrosamine as a contaminant i n concentrations ranging from 0.3 to 640 ppm. I t was postulated that n i t r i t e used as a c o r r o s i o n i n h i b i t o r i n the metal containers reacted with dimethylamine during storage. The fourth herbicide i s a formulation c o n t a i n i n g t r i f l u r a l i n ( ,
α

3

m ο S tn

5

Ο

H

m m

X

H

to

22.

Pesticidal

FISHBEIN

Trace

363

Contaminants

INSTRUMENT OPERATING PARAMETERS Column

T°C

Flow Rate 30 ml/min 30 ml/min

GLC-TEA

14 ft-1/8" 10% Carbowax-20M & 005% KOH on Chromosorb WHP-80/100

175

GLC-HALL DETECTOR

6 ft-1/4" 3% Carbowax-20M on Chromosorb W-80/100

120

HPLC-TEA HPLC-UV (254 nm)

2 - 3.9 mm ID χ 30 cm ii Porasil connected in Tandem

1.5 ml/min

HPLC Solvent Systems HPLC-UV Volatile Nitrosamines

15% Isopropanol in Iso-Octane

Non-Volatile Nitrosamines in: Triazine Herbicides Prowl Butralin

3% Dimethoxyethane in Iso-Octane plus 0 02% 75/25 (IsopropanolWater)

Diethanolamine Salts

50% Dimethoxyethane in Iso-Octane plus 0.02% 75/25 (Isopropanol Water)

HPLC-TEA Volatile Nitrosamines Non-Volatile Nitrosamines

10% Acetone in Iso-Octane

Diethanolamine Salts

40/60 Acetone Iso-Octane

Journal of Agricultural and Food Chemistry Figure 6.

Typical instrument operating parameters for GLC and LC analysis for nitrosamines (40)


THE

364

PESTICIDE

CHEMIST

A N DM O D E R N

TOXICOLOGY

Table 6 MISCELLANEOUS HERBICIDES SCREENED FOR NITROSAMINE . CONTAMINATION; OTHER PESTICIDES SCREENED FOR NITROSAMINE CONTAMINATION (40) t

Sample

GLCTEA. PPm

Ingredient

LC-TEA, ppm

LC-UV,ppm

233 DELNA*-

217 DELNA

Miscellaneous Herbicides N-19 N-68» N-70 N-81 N-86 N-88 N-89 N-41 N-60 N-76 N-77 N-84 N-7

3.6-dichloro-o-anisic acid diethanolamine salt of 2-sec-butyl-4.6-dinitrophenol 2-sec-butyl-4,6-dinitrophenol 3-(3.4-dichlorophenyl)-1.1-dimethylurea 3-(3.4-dichlorophenyl)-1.1-dimethylurea 2-ethoxy-2.3-dihydro-3.3-dimethyl-5-benzofuranyl methanesulfonate same as N-88 Other Pesticides

neg* 9 9 ™9 9

n e

n e

n e

n e

bis(dimethylthio)carbamoyl)disulfide diphenylamine sodium [4-(dimethylamino)phenyl]diazene sulfonate same as N-76 bis(dimethylthiocarbamoyl) disulfide 2.3.5-triiodobenzoic acid

9

neg neg neg neg neg neg

'Presumed to be diethanolamine salt. £ Less than 1 ppm. *Diethanolnitrosamine £ A blank indicates that the sample was not analyzed by that method.

Table

7

Alkyl Amines Used in Manufacturing Screened for Nitrosamine Contamination ( 4 0 )

Sample

Ingredient

N-28

dimethylamine dimethylamine triethanolamine diethanolamine dimethylamine

N-31 N-67 N-69 N-85

^Less than 1 ppm. that method.

GLCTEA, ppm

34 DMNA 28 DMNA

LCTEA, ppm

U

LCUV, ppm

GLCHall, ppm

26 DMNA 29 DMNA

neg^ neg 4 DMNA

6 DMNA

i*A blank indicates that the sample was not analyzed by


GLC-Hall, ppm

22.

FiSHBEiN

Pesticidal

Trace

365

Contaminants

I Sample | 100% Acetone f — Negative —

i

1

—

» Positive

.

\

INo Nitrosamines I '

1

«

5 0 % Acetone I Positive

10% Acetone

N-Nitrosodiethanol Amine

1 \

,

}

Negative

Positive

L_

.

[Other Non-Vol. Nitrosamines!

Journal of Agricultural and Food Chemistry

Figure 7.

Procedure for screening and identifying nonvolatile nitrosamines on LC-TEA showing the different solvent systems used (40)



Sample

Table 8

GC-TEA HPLC-TEA GC-TEA HPLC-TEA GC-TEA HPLC-TEA GC-MS

195 640 154

NDMA NDMA NDPA

352-250AA 264-92AA

acid as as

2.3.6-Trichloroben/oic DMA salt

2.3.6-Trichlorobenzoic DMA salt

'ND

α

m ο Χ m

Ο

Ο

Η

m C/î

M

Η

X

22.

FISHBEIN

Pesîicidal

Trace

Contaminants

367

detectable l e v e l s (,.~ re ο o r α) ω

Ο

CO

-Sf

CL

°i Ë 2 < LU

^ ce = ! ι— r—

The Pesticide Chemist and Modern Toxicology - ACS Publications

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