Search results for "Gas chromatography–mass spectrometry"
showing 10 items of 199 documents
Effect of simulated gastrointestinal digestion on plant sterols and their oxides in enriched beverages
2013
Abstract This study evaluates the bioaccessibility (percentage of soluble compound available for absorption) of plant sterols (PS) and their oxides (phytosterol oxidation products, POPs) after simulated gastrointestinal digestion in fruit (Fb), milk (M) and fruit-based milk beverages with (FbM a ) or without (FbM b ) tangerine juice. In beverages and their bioaccessible fraction (BF), campesterol, campestanol, stigmasterol, β-sitosterol and sitostanol were detected. Bioaccessibility of total PS ranged between 2.62 and 6.48%, FbM b yielding the highest value, followed by FbM a > Fb > M. Campesterol/campestanol were the most bioaccessible PS. Only oxides of β-sitosterol were detected in beve…
Development of microextraction techniques in combination with GC-MS/MS for the determination of mycotoxins and metabolites in human urine.
2017
Simple and highly efficient sample preparation procedures, namely, dispersive liquid–liquid microextraction and salting-out liquid–liquid extraction for the analysis of ten Fusarium mycotoxins and metabolites in human urine were compared. Various parameters affecting extraction efficiency were carefully evaluated. Under optimal extraction conditions, salting-out liquid–liquid extraction showed a better accuracy (84–96%) and precision (<14%) than dispersive liquid–liquid microextraction. Hence, a multibiomarker method based on salting-out liquid–liquid extraction followed by gas chromatography with tandem mass spectrometry was proposed. Satisfactory results in terms of validation were achiev…
Development of a GC–MS/MS strategy to determine 15 mycotoxins and metabolites in human urine
2014
The widespread mycotoxins contamination of food commodities has made the monitoring of their levels essential. To overcome the disadvantages of the indirect approach by food analysis, detection of mycotoxin as biomarkers in urine provides a useful and specific data for exposure assessment to these food contaminants. In this work, a sensitive, rapid and accurate method based on gas chromatography-tandem mass spectrometry procedure to determine 15 mycotoxins and metabolites in human urine was optimized and validated taking into consideration the guidelines specified in Commission Decision 2002/657/EC and 401/2006/EC. A salting-out assisted acetonitrile-based extraction was used for sample pre…
Multi-mycotoxin analysis in wheat semolina using an acetonitrile-based extraction procedure and gas chromatography–tandem mass spectrometry
2012
A new analytical method for the rapid and simultaneous determination of ten mycotoxins including patulin, zearalenone and eight trichothecenes (nivalenol, fusarenon-X, diacetoxyscirpenol, 3-acetyl-deoxynivalenol, neosolaniol, deoxynivalenol, T-2 and HT-2) in wheat semolina has been developed and optimized. Sample extraction and purification were performed with a modified QuEChERS-based (acronym of Quick, Easy, Cheap, Effective, Rugged and Safe) procedure and determined by gas chromatography (GC) coupled to triple quadrupole instrument (QqQ). This is the first paper on the application of GC-QqQ-MS/MS to analysis of mycotoxins. Careful optimization of the gas chromatography-tandem mass spectr…
Application of headspace solid phase dynamic extraction gas chromatography/mass spectrometry (HS-SPDE-GC/MS) for biomonitoring of n-heptane and its m…
2011
Abstract Solid phase dynamic extraction (SPDE) is an innovative sample preparation and enrichment technique in connection with gas chromatography (GC). Using SPDE, we developed a method for simultaneous determination of n-heptane and its mono-oxygenated metabolites heptane-4-one, 3-one, 2-one, 4-ol, 3-ol, 2-ol, and 1-ol in blood. After adjustment of various extraction and desorption parameters, method validation resulted in limits of detection (LOD) between 0.006 (heptane-4-one) and 0.021 mg/L (heptane-1-ol). Intra-assay coefficients of variation ranged between 4.8% and 20.8% while relative recovery ranged between 100% and 117% (spiked concentration 0.128 mg/L, n = 8). The method was appli…
Cocaine abuse determination by ion mobility spectrometry using molecular imprinting
2016
A cocaine-based molecular imprinted polymer (MIP) has been produced by bulk polymerization and employed as selective solid-phase extraction support for the determination of cocaine in saliva samples by ion mobility spectrometry (IMS). The most appropriate conditions for washing and elution of cocaine from MIPs were studied and MIPs were characterized in terms of analyte binding capacity, reusability in water and saliva analysis, imprinting factor and selectivity were established and compared with non-imprinted polymers. The proposed MIP-IMS method provided a LOD of 18μgL-1 and quantitative recoveries for blank saliva samples spiked from 75 to 500μgL-1 cocaine. Oral fluid samples were collec…
Comparison of Urinary On-Site Immunoassay Screening and Gas Chromatography-Mass Spectrometry Results of 111 Patients With Suspected Poisoning Present…
2007
On-site tests based on immunoassay techniques are widely used for toxicologic screening analysis in patients with suspected poisoning. However, such assays usually have been validated using urine samples with known concentrations of the investigated substances. In the present investigation, on-site screening results were evaluated in a clinical setting. This was a retrospective study of patients with suspected poisoning from January to December 2003 in the emergency department of a tertiary urban hospital. Urine samples were analyzed using the Triage 8 panel and gas chromatography-mass spectrometry (GC-MS). A total of 111 patients were included (54 female, 57 male; average age 37.8 +/- 19.7…
Detection of gamma-hydroxybutyrate in hair: Validation of GC–MS and LC–MS/MS methods and application to a real case
2012
A gas chromatography-mass spectrometry (GC-MS) and a liquid chromatography tandem mass spectrometry (LC-MS/MS) method were validated for quantifying endogenous and exogenous hair concentrations of gamma-hydroxybutyrate (GHB). The GC-MS method is based on overnight extraction of 25 mg hair in NaOH at 56 °C, liquid/liquid extraction in ethylacetate and trimethylsylil derivatization; analysis is by electron ionization and single ion monitoring of three ions. The LC-MS/MS method entails a rapid digestion of 25 mg hair with NaOH at 75 °C for 40 min, liquid/liquid extraction in ethylacetate and reconstitution of the extract in the LC mobile phase; negative ion electrospray ionization and multiple…
Concentrations of 9-Tetrahydrocannabinol and 11-Nor-9-Carboxytetrahydrocannabinol in Blood and Urine After Passive Exposure to Cannabis Smoke in a C…
2010
Cannabinoid concentrations in blood and urine after passive exposure to cannabis smoke under real-life conditions were investigated in this study. Eight healthy volunteers were exposed to cannabis smoke for 3 h in a well-attended coffee shop in Maastricht, Netherlands. An initial blood and urine sample was taken from each volunteer before exposure. Blood samples were taken 1.5, 3.5, 6, and 14 h after start of initial exposure, and urine samples were taken after 3.5, 6, 14, 36, 60, and 84 h. The samples were subjected to immunoassay screening for cannabinoids and analyzed using gas chromatography-mass spectrometry (GC-MS) for Delta(9)-tetrahydrocannabinol (THC), 11-nor-hydroxy-Delta(9)-tetra…
In vitro production of GHB in blood and serum samples under various storage conditions
2011
Abstract The in vitro production of GHB was observed in freshly collected, untreated whole blood samples using glass BD-Vacutainers and polypropylene S-monovettes. GHB concentrations were determined daily over a period of one week and after 3, 6 and 9 weeks again. Furthermore, the GHB concentration in 40 untreated random whole blood samples stored at 4 °C for a longer period of time (10 samples 12 month, 10 samples 24 month and 20 samples 36 month) was also determined. For comparison, the in vitro production of GHB in freshly collected and prepared serum samples was observed. GHB serum concentrations were determined three times over a period of one week and once again after six weeks. Sampl…