Analysis of impurities in seized MDMA tablets can be used to determine the synthesis method used and to identify links among exhibits. However, no standardized method exists to generate impurity profiles, limiting comparisons among different laboratories. This research investigated the effect of extraction procedure and gas chromatography temperature program on the resulting impurity profiles. ...

Investigations were carried out to determine whether flavor compounds characteristic for fresh cucumbers could be rapidly determined using a solid-phase microextraction (SPME) dynamic headspace sampling method combined with gas chromatography and flame ionization detection. Cucumbers were sampled, during blending, for fresh cucumber flavor compounds (E,Z)-2,6-nonadienal and (E)-2-nonenal. The G...

As part of a program aiming at the selection of yeast strains which might be of interest as sources of natural flavours and fragrances, the bioreduction of (4R)-(-)-carvone and (1R)-(-)-myrtenal by whole-cells of non-conventional yeasts (NCYs) belonging to the genera Candida, Cryptococcus, Debaryomyces, Hanseniaspora, Kazachstania, Kluyveromyces, Lindnera, Nakaseomyces, Vanderwaltozyma and Wick...

Solid phase microextraction (SPME) has been optimized and applied to the determination of the volatile halogenated compounds (VHCs) and semi-volatile halogenated compounds (SVHCs). Three types of SPME fiber coated with different stationary phases (PDMS-100 mum, CAR/PDMS-75 mum, PDMS/DVB-65 mum) were used to examine their extraction efficiencies for the compounds tested. Experimental parameters ...

285 Premium wine quality can be achieved only through a favorable balance between fruit, fermentation, and processingderived aromas and flavors. The 3-alkyl-2-methoxypyrazines produce vegetative odors characteristic of green bell peppers and peas. The olfactory threshold at which these compounds are sensed is extraordinarily low: 1 to 10 ng/L in water. These compounds, 3-isobutyl-2-methoxypyraz...

BACKGROUND The microbiological diagnosis of infectious diarrhoea may take several days using conventional techniques. In order to determine whether flatus can be used to make a rapid diagnosis, the volatile organic compounds associated with diarrhoea were analysed. METHODS Stool samples were collected from 35 patients with infectious diarrhoea and from six healthy controls. Gaseous compounds ...

A simple, rapid, and reliable method to detect residual levels of tert-butanol in liposomes using sec-butanol as an internal standard has been developed. Solid-phase microextraction (SPME) followed by gas chromatographic analysis was used to quantify the amount of residual tert-butanol in freeze-dried liposome material. Only 1 min was necessary for reproducible amounts of analyte to absorb onto...

Lung cancer is a leading cause of deaths in cancer. Hence, developing early-stage diagnostic tests that are non-invasive, highly sensitive, and specific is crucial. In this study, we investigated to determine whether biomarkers derived from urinary volatile organic compounds (VOCs) can be used to discriminate between lung cancer patients and normal control patients. The VOCs were extracted from...

Application of the headspace solid-phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC/MS) technique as an analytical tool to monitoring the degradation of phenolic compounds and the formation of by-products in produced water by UV photolysis and UV/peroxide is proposed. All of the experimental conditions for the degradation tests were carried out according to the respons...

This investigation is based on the automated solid phase microextraction GC-MS analysis of the volatile fraction of a variety of coffee bean matrices. Volatile analytes were extracted by headspace (HS)-SPME which was achieved with the support of automated instrumentation. The research was directed towards various important aspects relating to coffee aroma analysis: monitoring of the volatile fr...