A method was developed that offers a rapid, simple and accurate technique for the determination of chlorophenols at trace levels in aqueous samples with very limited volumes of organic solvents. These compounds were acetylated, then preliminarily extracted with n-hexane. The enriched chlorophenols were directly analyzed using gas chromatography with an electron-capture detector. The detection l...

Long-term antibiotic therapy is one of the main risk factors for mycosis. The urinary D-arabinitol/L-arabinitol (D-/L-ARA) ratio (a biomarker of several Candida species) was determined by gas chromatography with an electron capture detector in samples from 51 infants undergoing long-term antibiotic therapy. Although 47 of these children had higher D-/L-ARA ratios than healthy controls (P<0.0003...

A gas-liquid chromatographic method for the determination of T-2 toxin in plasma is described. The toxin is extracted with benzene, washed with aqueous sodium hydroxide, and chromatographed on a small Florisil column; the heptafluorobutyryl derivative is prepared by reaction with heptafluorobutyrylimidazole. The T-2 HFB derivative is chromatographed on OV-1 at 230 degrees C and measured with an...

In this paper a kinetic study is made of the biodegradability of Aroclor 1242 in sandy soil employing a mixed culture of acclimatized bacteria. The assays were done in stirred tank reactors, and the biodegradation process was monitored by High Resolution Gas Chromatography (HRGC) with Electron Capture Detector. These results are supported by other indirect measurements and indicators of the exi...

Soft tissues of species of marine fauna; crabs (Crustacea), oysters (Pelecypoda, Bivalvia), sea stars (Asterroidea), sea urchin (Echinoidea) and bony fishes (Osteichtyes) sampled along the Kenya-Mombasa coastal region were analyzed to determine the levels of organochlorine pesticides (OCPs). Analysis was done using gas chromatography with an electron capture detector. This study showed that mar...

In this study, the efficiency of a clean-up method by gel permeation chromatography (GPC) for the separation of pesticides from lanolin is analyzed. The pesticides analyzed belong to two different families, organophosphorous and synthetic pyrethroids. Lanolin, a standard mixture of the pesticides, and a lanolin-pesticides mixture are injected in a GPC column. The recoveries and elution times fr...

A headspace solid-phase microextraction method has been developed for the determination of 8 pesticides in vegetables and fruits by using gas chromatography with an electron capture detector. Two types of fibers (polyacrylate, 85 microm and polydimethylsiloxane, 100 microm) have been assayed and compared. The main factors: extraction and desorption parameters, ionic strength, and the effects of...

Scanning electron microscopes (SEMs) are usually equipped with two types of detectors: secondary and backscattered electron detectors. The former produces secondary electron images (SEI) rich in topographic information[1, 2], whereas the latter produces backscattered electron images (BEI) rich in composition information[3]. Recently, however, a few other detectors have been installed in additio...