A study of large-volume on-column injection GC-ECD for the ultratrace analysis of organochlorine pesticides in water.

In this work, a large-volume on-column injection method for the analysis of 21 organochlorine pesticides, including HCH isomers, DDT derivatives and cyclodiene derivatives, was optimized. The solvent selected to carry out the study was ethyl acetate and the injection volume was 100 microl. Some factors were introduced in a Plackett-Burman design to determine their influence in the vaporization efficiency.

Determination of organic anions in atmospheric aerosol samples by capillary electrophoresis after reversed pre-electrophoresis.

This work presents the determination of low-molecular-mass (LMM) organic acids by CE after extraction with MeOH and preconcentration by evaporation. The interference arising from the simultaneous concentration of fast mobile anions (chloride, nitrate, and sulfate) at levels 200 times higher than those of LMM organic acids was reduced by the application of reversed pre-electrophoresis (RPE) as clean-up technique. This methodology allows for an effective elimination of high levels of fast mobile anions from the capillary before the separation has taken place, although analytes are also partially eliminated according to their electrophoretic velocities.

Pressurized liquid extraction of organochlorine pesticides from certified solid materials.

In order to propose a versatile method to use in laboratories devoted to environmental analysis, a scheme for the determination of organochlorine pesticides from different solid matrices is evaluated. Pressurized liquid extraction is chosen as the sample preparation technique, followed by the purification of the extract by means of solid-phase extraction with Envi-carb cartridge (100 m(2)/g). Finally, the extracts are analyzed by programmed temperature vaporization (PTV)-gas chromatography (GC)-electron-capture detection and PTV-GC-mass spectrometry.

Capillary electrophoretic method for the determination of inorganic and organic anions in real samples. Strategies for improving repeatability and reproducibility.

Selectivity and robustness of the pyromellitic acid (PMA) based background electrolyte was improved in order to increase its applicability for routine analysis of inorganic and organic anions in real samples. An electrolyte composed of 6.75 mM PMA, 0.

Evaluation of HCH isomers and metabolites in soils, leachates, river water and sediments of a highly contaminated area.

In this work we evaluate the contamination caused by HCH residues in the soil, leachates, river water and sediments of an industrial estate of the NW of Spain. We study the distribution of the isomers in the different matrices, analysing 37 soil samples, collected in eight points at several depths, six natural leachates, four river water samples and three river sediments. Soil and leachate samples present very high levels of HCH isomers, higher than the established by legislation, and some pesticides were also detected in the analysed river water whereas no pesticides were detected in the river sediments.