Analysis of Pesticide Residues by Chemical Derivatization. II. N-Methylcarbamates in Natural Water and Soils

1976 ◽  
Vol 59 (1) ◽  
pp. 188-196
Author(s):  
John A Coburn ◽  
Brian D Ripley ◽  
Alfred S Y Chau
Keyword(s):  
Potassium Hydroxide ◽  
Natural Waters ◽  
Extraction Procedure ◽  
Potassium Hydroxide Solution ◽  
Gas Liquid Chromatography ◽  
Chemical Derivatization ◽  
Hydrolysis Products ◽  
Acid Esters ◽  
Phthalate Acid Esters

Abstract A method for the quantitative determination of several N-methylcarbamates in natural waters and the applicability of the derivative to soil samples using a previously published extraction procedure are described. After extraction of the carbamates from the substrate, the carbamates are hydrolyzed in a 10% methanol-potassium hydroxide solution to form the phenolic hydrolysis products, which are isolated and derivatized with pentafluorobenzyl (PFB) bromide to produce the PFB ether derivatives. The PFB derivatives are cleaned up and fractionated on a silica gel microcolumn and determined by electron capture gas-liquid chromatography (GLC). Eight organophosphate pesticides and 2 phthalate acid esters that hydrolyze to phenols or phthalic acid were evaluated as potential interferences and were found not to interfere with any of the carbamates tested. Quantitative determinations of 0.1 μg carbofuran and 3-ketocarbofuran and 0.5 μg carbaryl, metmercapturon, and Mobam in a 1 L water sample are possible. Propoxur was not determined at levels <1 μg/L due to the short GLC retention time of the derivative and interferences from the reagents at the lower levels.

Confirmation of Pesticide Residue Identity. VIII. Organophosphorus Pesticides

1974 ◽  
Vol 57 (6) ◽  
pp. 1272-1278
Author(s):  
John A Coburn ◽  
Alfred S Y Chau
Keyword(s):  
Liquid Chromatography ◽  
Electron Capture ◽  
Potassium Hydroxide ◽  
Methyl Parathion ◽  
Organophosphorus Pesticides ◽  
Potassium Hydroxide Solution ◽  
Gas Liquid Chromatography ◽  
Flame Photometric Detector ◽  
Hydrolysis Products ◽  
Pentafluorobenzyl Bromide

Abstract A chemical confirmation for 5 organophosphorus pesticides is described. After extraction and quantitation by flame photometric detector gas-liquid chromatography (CLC), the organophosphorus pesticides are hydrolyzed in a 10% methanolic-potassium hydroxide solution, followed by derivatization with pentafluorobenzyl bromide to produce the pentafluorobenzyl (PFB) ethers of the phenolic hydrolysis products. The PFB ethers are subsequently fractionated on a silica gel microcolumn, and analyzed by electron capture GLC. The preliminary chromatographic results of the electron capture GLC analysis of the PFB ethers of the phenolic hydrolysis products of several N-methylcarbamates are also presented. As little as 0.01 ppb ronnel and crufomate and 0.10 ppb parathion, fenitrothion, and methyl parathion in a 1 L water sample can be confirmed.

Determination of phthalate acid esters plasticizers in polyethylene terephthalate bottles and its correlation with some physicochemical properties

2018 ◽  
Vol 68 ◽  
pp. 87-94 ◽  
Author(s):  
Daniel Salazar-Beltrán ◽  
Laura Hinojosa-Reyes ◽  
Carlos Palomino-Cabello ◽  
Gemma Turnes-Palomino ◽  
Aracely Hernández-Ramírez ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Polyethylene Terephthalate ◽  
Polyethylene Terephthalate Bottles ◽  
Acid Esters ◽  
Phthalate Acid Esters

Gas-Liquid Chromatographic Determination of Residues of Chlorpyriphos and Leptophos, Including their Major Metabolites, in Vegetable Tissue

1974 ◽  
Vol 57 (1) ◽  
pp. 182-188 ◽  
Author(s):  
Heinz E Braun
Keyword(s):  
Liquid Chromatography ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Aqueous Sodium ◽  
Hydrolysis Products ◽  
Aqueous Sodium Carbonate ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Hydrolysis Of

Abstract A method is described for the determination of residual chlorpyriphos (O, O-diethyl 0-3,5,6- trichloro- 2 - pyridyl phosphorothioate) and leptophos (O-(4-bromo-2,5-dichlorophenyl) O-methyl phosphonothioate), and their respective oxygen analogs and hydrolytic metabolites, in field-treated vegetables. Samples are extracted by blending with acetonitrile followed by liquid-liquid partitioning between benzene and aqueous sodium carbonate to separate the parent compounds and oxygen analogs from the hydrolytic metabolites. Both fractions are individually cleaned up on silica gel which also serves to fractionate the parent compounds from their oxygen analogs as the result of oncolumn hydrolysis of the oxygen analogs. Chlorpyriphos and leptophos are determined by flame photometric gas-liquid chromatography (GLC); the residual and derived hydrolysis products are derivatized with trimethylsilyl acetamide and determined by electron capture GLC. Overall recoveries from fortified samples averaged 95% for the parent compounds and 85% for the oxygen analogs and hydrolytic metabolites. Detection limits approximated 0.005 ppm for chlorpyriphos and leptophos, 0.002 ppm for the oxygen analogs, and 0.001 ppm for the hydrolytic metabolites.

Comparison of Carr-Price Analysis and Liquid Chromatographic Analysis for Vitamin A in Fortified Milk

1985 ◽  
Vol 68 (1) ◽  
pp. 56-58
Author(s):  
Robert S Mills
Keyword(s):  
Vitamin A ◽  
Potassium Hydroxide ◽  
Extraction Procedure ◽  
Hexane Extraction ◽  
Average Value ◽  
Fortified Milk ◽  
Liquid Chromatographic Analysis ◽  
Price Analysis ◽  
Liquid Chromatographic

Abstract The determination of the vitamin A concentration in fortified milk was compared using Carr-Price analysis and liquid chromatography (LC). Carr-Price analysis required saponification of the sample with alcoholic potassium hydroxide, extraction with ether, and colorimetry with antimony trichloride in chloroform. LC analysis required hexane extraction of a 71% alcohol-sample solution and centrifugation at 2000 rpm. A 100 μL aliquot of the extract was analyzed on a LiChrosorb Si-60, 5 μm column, using an ethyl ether-hexane (2 + 98) mobile phase and detection at 313 nm. Each method was statistically evaluated for precision and sample-to-sample reproducibility. The LC extraction procedure was examined for efficiency. Each LC value was divided by the Carr-Price value obtained for the same sample; an average value of 0.975 with a coefficient of variation of 6.90% was obtained. It was concluded that the procedures were statistically equivalent.

Determination of phthalate acid esters (PAEs) in carbonated soft drinks with MSPE/GC–MS method

Toxin Reviews ◽  
2017 ◽  
Vol 37 (4) ◽  
pp. 319-326 ◽  
Author(s):  
Mojtaba Moazzen ◽  
Amir Hossein Mahvi ◽  
Nabi Shariatifar ◽  
Gholamreza Jahed Khaniki ◽  
Shahrokh Nazmara ◽  
...  
Keyword(s):  
Soft Drinks ◽  
Carbonated Soft Drinks ◽  
Acid Esters ◽  
Phthalate Acid Esters
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