ABSTRACT
This paper describes a gas chromatographic method for the determination of combined residues of prochloraz and its metabolites in various plant materials, including vegetables, fruits, seeds, grains and roots. The method is much simpler than previous ones as it does not require steam distillation; it consists of preliminary extraction of the sample, hydrolysis with pyridine hydrochloride in a test tube, extraction of the 2,4,6-trichlorophenol without the aid of steam distillation/continuous extraction, derivatization with diazomethane and gas chromatographic determination using electron-capture detection. The method is very rapid and can be done in a test tube; detection limit is from 0.01 to 0.50 mg/kg; recoveries are dependent on concentration of analyte and sample matrix; the determined values were found in the region of 72-102%.
Subject(s)
Chromatography, Gas/methods , Fruit/chemistry , Fungicides, Industrial/analysis , Imidazoles/analysis , Pesticide Residues/analysis , Triticum/chemistry , Vegetables/chemistry , HydrolysisABSTRACT
A gas chromatographic system for the evaluation of linear temperature-programmed retention indices allowing n-alkanes to be adopted as the reference retention markers for any type of analyte, irrespective of the atoms present in their molecules, is described. It is based on the simultaneous use of two different detectors (a flame ionization detector and a specific detector suitable for the sample components), both connected (in parallel) to the same column outlet. The performance of this system has been tested by measuring the retention indices of fifteen chlorinated pesticides under conditions of linear programming temperature, by adopting an electron-capture detector as the specific detector. The reliability of the retention indices thus determined has been proven by verifying that they can be reproduced under different chromatographic conditions.