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Chromatographic scince series - Cazes J.

Cazes J. Chromatographic scince series - Marcel Dekker, 1996. - 1098 p.
ISBN 0-8247-9454-0
Download (direct link): сhromatography1996.pdf
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6
7
766 Fodor-Csorba
Gardona
DDT
HCH
Chlorophos
Dimethoate
Dimethoate oxygen analog Dioxathion Disulfoton Fonofos Fonofos oxygen analog Oxydemethon methyl Diazinon OP compounds
OP compounds
OP compounds Dichrotophos
Ethion
Fcnsulfothion Oxydemetonmethyl Phosmet T richlorfon
Silufol UV254 CHCI,-acetone
(AgNO, impr.)
Silica gel F (I) 2.2.4-trimethylpentane-
(Eastman-Kodak) methylcyclohexane-i-amyl
alcohol-paraffin oil-acetone (4:2:2:.': 1 (
(2) n-heptane-xylene-benzene: toluene:cyclohexane-methylcyclohexane 11.1:1:1 1)
Silica gel F254 or R.
containing 5% Ti02 Silica gel R Alumina R (neutral)
Silica gel G impregnated with salts or phenol Silica gel IB (Baker-flex)
Petroleum ether-benzene-EtOAc (50: 15:5)
Petroleum ether-benzene-EtOAc (65 : 30: 5); temperature-programmed gradient elution Hexane-xylene-EtOAc-acetone (50: 15 :5 : 18)
2,2.4-trimethylpentane-methylcyclohexane-hexyl alcohol-acetone (18:9:9:9)
0.1
[mg/kg]
(1) (2)
AgNO,-NH4OH 33
12
68
75 49
56
61
7
74
Pynacryptol yellow
Thioacridon 0.1 - I
Water
I2 vapor
Table 3 (continued)
Compound Stationary phase Mobile phase Detection Limit of Sample Ref.
detection
R, x 100 (/xg)
Phospholan
Metaphos Silica gel-gypsum-Zn Hexane-acetone p-dimethylaminoben- Vegetables 8
(4:1) zaldehyde-AcOH
Hexane-ether (1:1) Dry fruit
Phosphamide Silica gel-starch Hexane-acetone (1:1) PdCL
Chlorophos Silica gel-,
Chlorpyrifosmethyl Silica gel 60 CH2C1, 65
I' 254
Tetramethrin
Piperoxylbutoxide
Pesticides
769
Ethion and the very toxic phorate can be separated in the presence of six other OP insecticides with the 2,2,4-trimethylpentane-hexane-chloroform (18:18:12) system (64) (Table 3). OP content of vegetables and dried food samples was investigated on the appropriate plates. Silica gel-gypsum-zinc powder support was used for methafos, and silica gel-starch or silica gel-aluminum oxide coating for chlorofos and phosphamide determination. These results were compared with gas chromatography
(8) (Table 3). Chloropyrifos methyl, tetramethrin, and piperoxyl butoxide were determined as active ingredients of a pesticide product (65) (Table 3).
Several reviews summarized the recently published methods for the OP insecticides and their metabolites in food, feed, and environmental samples (25a-e).
Tabun, Sarin, Soman, DFP, and VX, organophosphorus warfare compounds, were detected and determined by OPLC in the presence of 20 different types of pesticides such as , OP, carbamates, and carbamides. The determination of these compounds was disturbed by the structurally related OP insecticides. The chromatographic separation was studied by two dimensional TLC. The multicomponent eluent system was optimized by the PRISMA model.
The mobile phase diisopropyl ether-benzene-tetrahydrofurane-n-hexane (10:7:5:11) was used in one direction and tetrahydrofurane-w-hexane (2:3) in the other direction on silica gel 60 plates without fluorescence indicator. Visualization was based on enzyme inhibition with cholinesterase, with butyrylthiocholine iodide serving as the substrate. After spraying with cobalt chloride, the enzyme inhibiting substances appeared as blue spots against a white background. The limit of detection was between 15-100 pg. (65a).
The degradation of isazofos was studied in soil samples under field and laboratory conditions. After incubation, l4C labeled isazofos residues were extracted with acetone-methanol (1:1) and acetone-methanol-dichloromethane (1:1:1). The extracts were chromatographed on silica gel plates developed with chloroform-ethyl acetate-hexane-acetic acid (12:12:6:1). The original isazofos was observed at Rf 0.89 and 5-chloro-l-isopropyl-3-triazolol at Rf 0.49. The pH of the soil had a great influence on the degradation of isazofos (65b).
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