Search results for "Gas Chromatography"
showing 10 items of 750 documents
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…
Exposure assessment of fruits contaminated with pesticide residues from Valencia, 2001– 03
2006
A total of 634 samples of oranges, tangerines, peaches, nectarines, khakis and watermelons were collected from an Agricultural Valencia Community Cooperative during the May 2001 to April 2003 campaigns and they were analysed for 15 pesticides among those recommended for pest treatment. A conventional multiresidue analytical procedure based on ethyl acetate extraction was used followed by gas chromatography coupled to a nitrogen phosphorus detector for routine analysis; and mass spectrometry was performed for confirmation. Recovery studies with spiked samples at 0.5 mg kg-1 for each pesticide ranged from 52% for acephate to 87% for fenthion with a standard deviation20%. Limits of quantificat…
Multi-occurrence of twenty mycotoxinsin pasta and a risk assessment in the moroccan population
2018
In the present study, the multi-occurrence of twenty (20) mycotoxins in pasta samples consumed in Morocco was assessed. For this, a modified Quick, Easy, Cheap Effective, Rugged, and Safe method was validated. The mycotoxins studied were identified and quantified by liquid chromatography&ndash
Risk assessment of benzene in food samples of Iran's market
2018
Abstract The concentration of benzene in ninety-eight collected food and drink samples (carbonated beverage, fruit juice, pickle, lime juice, mayonnaise and salad dressing, 16 samples from each) from Iran local markets were investigated using gas chromatography equipped with flame ionization detector (GC-FID). Moreover, the correlation of benzene concentration with sodium benzoate and ascorbic acid concentrations was assessed. Benzene concentration in carbonated beverages, fruit juices, pickle, lime juices, mayonnaise and salad dressing were 3.57 ± 1.70, 5.17 ± 3.63, 4.37 ± 2.24, 4.99 ± 0.54, 1.38 ± 0.87 and 1.47 ± 0.83 μg/L, respectively, being in all cases below the acceptable limit (10 μ…
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…
A new approach to examine the relationships between sensory and gas chromatography-olfactometry data using generalized procrustes analysis applied to…
2003
Six French Chardonnay wines were submitted to both sensory and combined headspace/gas chromatography-olfactometry analyses. The detection frequencies allowed five hierarchical levels to be distinguished: P25, the odorant areas (OAs) having a detection frequencyor =25% (the complete olfactogram without the odor noise); P40,or =40%; P55,or =55%; P70,or =70%; and P85,or =85%. Moreover, the detection frequencies were analyzed to distinguish 21 discriminative OAs. Wines tested by sensory analysis and the headspace samples analyzed by gas chromatography-olfactometry (GC-O) were described by a heterogeneous vocabulary distributed into nine overall classes of descriptors. The new statistical treatm…
Development and validation of a reliable method for studying the distribution pattern for opiates metabolites in brain
2012
Abstract Brain distribution pattern of “street” heroin metabolites (morphine and codeine) was investigated in two fatalities due to “acute narcotism”. A suitable sample pretreatment prior to solid-phase-extraction was developed to achieve a good recovery of the analytes and to eliminate the interfering species. After derivatization with MSTFA, samples were analyzed by GC/MS. Specificity, accuracy, precision and linearity of the method were evaluated; LOD and LOQ were, respectively, 10 ng/25 ng for morphine and 5 ng/10 ng for codeine. This method was applied to the analysis of six brain areas (hippocampus, frontal lobe, occipital lobe, nuclei, bulb and pons) coming from two cases of heroin-r…
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…
Serum concentrations of persistent organic pollutants (POPs) in the inhabitants of a Sicilian city.
2012
Polychlorinated biphenyls (PCBs) and organochlorine pesticides are common environmental contaminants that have been associated with human health problems. OBJECTIVES: To assess serum concentrations of several organochlorine contaminants in general population living in a city with an ancient agricultural tradition and to identify possible exposure sources in Sicily. METHODS: A cross-sectional study was conducted on 101 individuals. Each participant answered a face-to-face questionnaire submitted by well-trained personnel and provided a serum sample which was analyzed for the concentrations of PCBs, HCB, HCHs and DDTs by using gas-chromatography coupled with mass spectrometry. RESULTS: HCB, p…