Pesticide residues in fruit and vegetables were determined by gas chromatography/tandem mass spectrometry (GC/MS/MS). Electron impact (EI)/MS/MS and chemical ionization (CI)/MS/MS were developed for 80 compounds, including organochlorine, organophosphorus, organonitrogen, and pyrethroids, providing unambiguous spectral confirmation for these complex matrixes. Residues were extracted from samples with acetone followed by a mixture of dichloromethane–petroleum ether. Two injections per sample were required for analysis of the entire pesticide list by EI/MS/MS and CI/MS/MS.Initial steps involving cleanup and concentration of extracts were eliminated. The excellent selectivity and good linearity allowed quantification and identification of low levels of pesticides in the most difficult matrixes. The method has been used for routine analysis of many vegetables.

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The bioconcentration of fenitrothion in the brain of the european eel (Anguilla anguilla) and its posterior elimination have been studied. Animals were exposed to a sublethal concentration of fenitrothion (0.04 mg/L) for 96 hours in a flow-through test system. After this pesticide exposure, animals were transferred to clean water for 72 hours more. Bioconcentration and elimination processes of fenitrothion were studied in blood and brain. This insecticide showed a strong tendency to bioconcentrate into selected tissues. A steady-state was observed in blood in few hours. Highest accumulation was detected in brain, where any steady-state could be observed. Elimination started rapidly from both tissues when a recovery period was allowed. Elimination kinetics were adjusted to one-compartment model. K2 of 0.015 and 0.044 hr-1 were calculated for fenitrothion in blood and brain. These K2 values were related with a relatively short half-live of fenitrothion in the analyzed tissues; probably due to the low biotransformation rate of this toxicant in the european eel. That fact would protect the animals against many biotransformation products even more toxic than the parent fenitrothion.

АннотацияКлючевые слова . В мировой практике используют различное лабораторное оборудование для подготовки проб, с помощью которого реализуется пробоподготовка. Установки для проведения пробоподготовки, принцип действия которых основан на методе вакуумной сепарации, производятся в США, Германии и др. Выпускается пре-имущественно автоматизированное оборудование, способное подготовить боль-шое количество проб за одну процедуру пробоподготовки [4]. В качестве выделя-емых высокомолекулярных структур могут выступать ДНК, РНК, различные бел-ковые соединения. Одной из самых важных структур, подвергаемых исследова-нию, является ДНК.Существует ряд причин, препятствующих массовому использованию обо-рудования для пробоподготовки. Главная из них -отсутствие равномерного прохождения растворов ДНК через рабочие ячейки [5]. Неравномерность про-хождения жидкости через ячейки при полной автоматизации процесса может привести к тому, что часть исходного раствора останется в одной или несколь-ких рабочих ячейках, тем самым не позволит провести очистку раствора и по-лучить пробу, удовлетворяющую условиям проведения молекулярно-биологических исследований.