DDT degradation during enhanced solid-liquid extractions. A consideration.

Analysis of p,p'-DDT in solid environmental samples, like soil or sediment, requires monitoring the breakdown of this insecticide during sample preparation and measurement, which produces mainly p,p'-DDD and p,p'-DDE. The occurrence of matrix-enhanced p,p'-DDT degradation during GC injection is a well-known phenomenon; careful cleaning and pre-treatment of the GC injection port enables for an overcoming of this problem. Modern solid-liquid extraction methods apply high temperatures and/or pressures to enhance the extraction kinetics and diffusion rates of the target compounds from the solid matrix.

Comparative study of turbulent solid-liquid extraction methods for the determination of organochlorine pesticides.

The aim of any extraction method in analytical chemistry is to effectively separate the analytes from the matrix with minimal solvent and time required. In this study, a comparison of the classical Soxhlet extraction and some new turbulent solid-liquid extraction techniques, such as fluidized-bed extraction (FBE), modified dive-in fluidized-bed extraction (dive-in FBE), modified dive-in Soxhlet extraction (dive-in SE) and dive-in thimble extraction (dive-in TE) for the determination of organochlorine pesticides (OCPs) was carried out. The turbulent extraction methods were performed by using the fexIKA vario control series extractor and by modification of the extraction system to dive-in technique, respectively.

Chemometrical classification of pumpkin seed oils using UV-Vis, NIR and FTIR spectra.

The main outcome of this work is elaboration of classification models for edible oil samples representing the most widespread brands of Austrian pumpkin seed oil. A complete spectral characterisation of the pumpkin seed oil samples by UV-Vis, NIR and FTIR spectra was obtained together with their basic sensorial classification. Chemometrical processing of the measured data enabled the detection of the most important spectral features, which are crucial for categorising the oils into two or three classes according to their sensory quality evaluated by a panel of experts.

Microwave-assisted derivatization of 2,5-hexanedione in urine: evaluation using GC-MS and GC-ECD.

2,5-Hexanedione, the main metabolite of n-hexane, can be responsible for axonal degeneration symptoms via formation of pyrrol-adducts with several amino acids. In order to make it amenable to gas chromatographic analysis, a protocol including microwave assisted derivatization is presented and compared to state-of-the-art technique of urine analysis. The applied methodology includes derivatization with O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine, extraction of the oximes and final analysis using either GC-MS or GC-muECD.

Comparison of different extraction techniques for the determination of chlorinated pesticides in animal feed.

The performances of Soxhlet extraction, dive-in Soxhlet extraction, microwave-assisted extraction (MAE), accelerated solvent extraction (ASE), fluidized-bed extraction (FBE), and ultrasonic extraction (UE) for the analysis of organochlorine pesticides in animal feed have been investigated. ASE and MAE provided significantly better extraction efficiency than Soxhlet extraction. The concentrations were 126.

Occurrence of triazines in surface and drinking water of Liaoning Province in Eastern China.

The Liaoning Province in Eastern China has a prosperous economy and traditional agricultural background. Steadily increasing water demand implies the direct use of surface water for drinking water support and foodstuff production. Due to the extensive use, high persistence, water solubility and relatively weak adsorptivity, the chloro s-triazines contaminate the aquatic environment and are therefore regularly and most frequently detected in ground and surface water.

Optimized extraction of polycyclic aromatic hydrocarbons from contaminated soil samples.

A comparison of Soxhlet extraction and a new extraction technique, fluidized-bed extraction, has been conducted. The extraction of polycyclic aromatic hydrocarbons (PAHs) by this new technique has been optimized considering as experimental variables the variation of the number of extraction cycles and the holding time after reaching the heating temperature by means of a surface response design. The significance of the operational parameters of the fluidized-bed extraction onto the performance characteristics has been investigated.

Triazines in the aquatic systems of the Eastern Chinese Rivers Liao-He and Yangtse.

The results of a one-year monitoring program on the two Eastern Chinese River systems, i.e. the Liao-He and the Yangtse, with special emphasis on the presence of triazine herbicides are presented.