Rapid Fluorimetric Method to Detect Total Plasma Malondialdehyde with Mild Derivatization Conditions

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Volatile Norisoprenoids as markers of botanical origin of Sardinian Strawberry-Tree (Arbutus unedo L.) Honey: Characterisation of Aroma Compounds by Dynamic Headspace Extraction and Gas Chromatography-Mass Spectrometry

In order to characterize and authenticate the aromatic profile of strawberry-tree (Arbutus unedo L.) honey, a dynamic headspace (DHS) extraction, followed by gas chromatography–mass spectrometry (GC–MS) analysis, was performed on 10 Sardinian strawberry-tree (Arbutus unedo L.) honey samples. A total of 28 aroma compounds were identified, but only norisoprenoid compounds such as a-isophorone, b-isophorone and 4-oxoisophorone, were recognized as specific floral origin markers of the strawberry- tree honey. The a-isophorone/b-isophorone ratio varied from 4 to 8, whereas the a-isophorone/4-oxoisophorone ratio was found to range from 11 to 20. The DHS extraction method was proposed as a valid alternative to pollen analysis for floral source detection, especially for products like strawberry-tree honey, characterized by a low pollen content

Development and validation of a solid phase micro-extraction-gas chromatography-mass spectrometry method for the determination of furan in baby food

An efficient and simple method for the determination of furan in baby-food (vegetables and fruits) by solid phase micro-extraction-gas chromatography-mass spectrometry (SPME-GC-MS) was developed and validated. Experimental design was used to investigate the effects of temperature and time of extraction. The calculated regression model was used to find the experimental conditions providing the optimal SPME extraction yield. Validation was carried out in terms of limit of detection (LOD), limit of quantitation (LOQ), linearity, precision and trueness. LOD and LOQ values in the low ng kg(-1) were achieved, whereas linearity was established over two order of magnitude. Good precision was obtained both in terms of intra-day repeatability and between-day precision on two concentration levels (RSD% lower than 3.6%). Recovery values of 91.5 +/- 6.2% and of 96.1 +/- 1.3% (n = 3) were calculated at 75 ng kg(-1) and 75 ng kg(-1) level. Finally, the applicability of the method to the determination of furan in a number of commercial and home-made baby-food samples was demonstrated

Use of experimental design for the purge-and-trap-gas chromatography-mass spectrometry determination of methyl tert-butyl ether, tert-butyl alcohol and BTEX in groundwater at trace level

An efficient method for the simultaneous determination of methyl tert.-butyl ether, tert.-butyl alcohol, benzene, toluene, ethylbenzene and xylene isomers in groundwater by purge-and-trap-gas chromatography-mass spectrometry was developed and validated. Experimental design was used to investigate the effects of temperature of extraction, time of extraction and percentage of salt added to the water samples. Regression models and desirability functions were applied to find the experimental conditions providing the highest global extraction yield. Validation was carried out in terms of limits of detection (LOD), limits of quantitation (LOQ), linearity and precision. LOD values ranging from 2.6 to 23 ng l(-1) were achieved, whereas linearity was statistically verified over two orders of magnitude for each compound. Precision was evaluated testing two concentration levels. Good results were obtained both in terms of intra-day repeatability and intermediate precision: RSD% lower than 4.5% at the highest concentration and lower than 13% at the lowest one were calculated for intra-day repeatability. A groundwater sample suspected of contamination by leaking underground petroleum storage tanks was analysed and some of the analytes were detected and quantitated

Improved determination of chlorophenols in water by solid-phase microextraction followed by benzoylation and gas chromatography with electron capture detection

A rapid method for the determination of chlorophenols in drinking water by solid-phase microextraction and gas chromatography with electron capture detection was developed and validated. A fused silica fiber coated with a 65 pm thick stationary phase of poly (dimethylsiloxane)/divinylbenzene was used to extract chlorophenols after performing in situ derivatisation with pentafluorobenzoyl chloride in the polymeric coating. Validation was carried out in terms of limits of detection (LOD), limits of quantitation (LOQ), linearity and precision. In situ derivatisation and the choice of a fiber with more affinity towards the derivatised analytes gave LODs in the 0.005 - 0.8 mug L-1 range which are lower values than those reported in previous work using poly(dimethylsiloxane) or poly(acrylate) fibers. Linearity was statistically verified over one order of magnitude for each compound. The production of chlorophenols as disinfection by-products in the treatment of drinking water with chlorine was studied over a period of eight days: mono-, di- and trichlorophenols were detected and quantitated

Development and validation of novel DH-GC-ITMS methods for the determination of Freon F-141b in formulated polyol and rigid polyurethane foam

Two efficient methods for the determination of 1,1-dichloro-1-fluoroethane (Freon F-141b) in formulated polyol and rigid polyurethane foam by dynamic-headspace-gas chromatographyion trap-mass spectrometry were developed and validated. Rigid polyurethane foam was efficiently dissolved in dimethylformamide by beating at the temperature of 60 degreesC for 2 h. Validation was carried out in terms of limits of detection (LOD), limits of quantitation (LOQ), linearity, precision and recovery. LOD values of 4.00 mug kg(-1) for rigid polyurethane foam and 0.73 mug kg(-1) for formulated polyol were achieved, whereas linearity was statistically verified over one order of magnitude. Precision was evaluated testing two concentration levels. Good results were obtained both in terms of intra-day repeatability and between-day precision: RSD % lower than 4% (n = 6) at the concentration of 15 mug kg(-1) were calculated for intra-day repeatability. Extraction recoveries up to 92.6+/-1.6% (n = 3) were also calculated by the addition of Freon F-141b to the samples analysed. Both the methods were applied for the analysis of a number of formulated polyol and rigid polyurethane foam samples