Journal of chromatography. A
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The objective of this paper is to investigate the potential of multiple headspace-solid-phase microextraction (MHS-SPME) for the determination of volatile compounds in complex matrix samples. A method based on MHS-SPME for the determination of around 20 volatile compounds, responsible of tomato flavour and aroma has been developed and validated, using gas chromatography with mass spectrometry (ion trap analyser) for analysis. For this purpose, the experimental beta parameter, resulting from the MHS-SPME theoretical development, has been obtained from real sample analysis (in triplicate) for each identified compound, carrying out up to 5 consecutive extractions. ⋯ Limits of detection were in the range of 0.25-5 ng/g. MHS-SPME has been proved to be an adequate technique to avoid matrix effects in complex samples quantitation. Its applicability to the determination of volatile tomato components, together with its limitations, is discussed in this article.
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There are a lot of taxonomic classifications of the genus Heracleum, and many authors indicate they need revision. Morphological identification is difficult to perform, as there are only few characteristic differences between each Heracleum species, varieties and forms. Furanocoumarins are characteristic compounds for the Apiaceae family, and they can be found in the whole genus in large quantities. ⋯ The method is characterised by high specificity, precision, reproducibility and stability values. It is for the first time that graft TLC is used for constructing fingerprints of herbs. The complete separation of ten structural analogues, by combining gradient TLC with the unidimensional multiple development technique, has not been reported yet.
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A screening tool was proposed for the rapid detection of eight priority volatile organic pollutants according to European standards in drinking water. The method is based on the direct coupling of a headspace sampler with a mass spectrometer, using a chromatographic column heated to 175 degrees C as an interface. ⋯ An appropriate chemometric treatment of these signals permitted them to be classified, on the basis of their volatile composition, as contaminated or uncontaminated with respect to the legally established concentration levels for these compounds in drinking water, and providing no false negatives. A conventional confirmation method was carried out to analyze positive water samples by using the same instrumental setup as in the screening method, but using an appropriate temperature program in the chromatographic column to separate, identify and quantify each analyte.
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Kaletra is an important antiretroviral drug, which has been developed by Abbott Laboratories. It is composed of lopinavir (low-pin-a-veer) and ritonavir (ri-toe-na-veer). Both have been proved to be human immunodeficiency virus (HIV) protease inhibitors and have substantially reduced the morbidity and mortality associated with HIV-1 infection. ⋯ The relative standard deviation (RSD) were <6% for both lopinavir and ritonavir. Mean accuracies were between the designed limits (+/-15%). The robust and rapid LC/MS/MS assay has been successfully applied for routine assay to support bioavailability, bioequivalence, and pharmacokinetics studies.
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Cigarettes may contain up to 10% by weight additives which are intended to make them more attractive. A fast and rugged method for a cigarette-screening for additives with medium volatility was developed using automatic headspace solid phase microextraction (HS-SPME) with a 65 microm carbowax-divinylbenzene fiber and gas chromatography-mass spectrometry (GC-MS) with standard electron impact ionisation. ⋯ Furthermore, the method was optimized for quantitative determination of 17 frequently occurring additives. The practical applicability of the method was demonstrated for cigarettes from 32 brands.