Persistence of selected pesticides and their phenolic transformation products in natural waters using off-line liquid solid extraction followed by liquid chromatographic techniques

Determination of impurities in pesticides and their degradation products formed during the wine-making process by solid-phase extraction and gas chromatography with detection by electron impact mass spectrometry. I. Vinclozoline, procymidone and fenitrothion

The presence of degradation products of vinclozoline, procymidone and fenitrothion, and of impurities from their commercial formulations, was studied in white and red wines elaborated from spiked must. After solid-phase extraction the nature of the residues was established by gas chromatography with mass spectrometric detection. The structures of several degradation products and impurities are discussed and elucidated on the basis of their electron impact spectra. In elaborated wines the concentrations of the degradation products and impurities are lower than those of the original active ingredients. Aminofenitrothion and acetylamino-formyl-fenitrothion-oxon are the main residues of fenitrothion in wine. For dicarboximides, an alcohol derivative of vinclozoline was found in addition to 3,5-dichloroaniline.

Determination of impurities in pesticides and their degradation products formed during the wine-making process by solid-phase extraction and gas chromatography with detection by electron ionization mass spectrometry. II. Bromopropylate, trichlorphon, parathion-methyl and tebuconazole

The presence of degradation products of bromopropylate, trichlorphon, parathion-methyl and tebuconazole in white and red wines elaborated from musts spiked with commercial formulations of the pesticides was studied. Must and wine were subjected to solid-phase extraction followed by gas chromatography with electron ionization mass spectrometric detection. Alpha-bromophenylphenylmethanol, aminoparathion, acetylaminoparathion-oxon and dichlorvos have been identified as degradation products of bromopropylate, parathion-methyl and trichlorphon in wines, respectively. Moreover, the presence of additives and impurities of the formulations in elaborated wines has also been found.

Study of nitrophenols preconcentration using quinolin-8-ol immobilized on controlled-pore glass in the presence of iron(III). Chromatographic determination of dinoseb in lemon juice

The efficiency of an adsorbent consisting of quinolin-8-ol immobilized on controlled-pore glass which was packed in a minicolumn to preconcentrate nitrophenols in the presence of iron(III) has been established. Retention was carried out at acidic pH in the presence of 20 mM iron(III). Methanol-30 mM formic acid-sodium formate aqueous solution (pH 4.2) (65:35) was used in a one-step elution. Determinations were carried out by using liquid chromatography with detection at 350 nm. Determination of trace amounts of dinoseb in lemon juice was carried out with a minimum sample preparation. Recoveries were between 89 and 100% at 200-33 micrograms l-1. The maximum admissible concentration in fruit juice dictated by the Spanish and European Community legislation can be measured.