Search results for " Analytical Chemistry"

Magnetic molecularly imprinted polymers for the selective determination of cocaine by ion mobility spectrometry

2018

Abstract Magnetic molecularly imprinted polymers (MMIPs) were prepared for cocaine recognition by bulk polymerization in the presence of magnetic nanoparticles (MNPs). Two reagents (polyethylene glycol (PEG) and 3-(trimethoxysilyl)propyl methacrylate (V)) were used for MNPs modification. MMIPs were characterized and compared in terms of loading capacity, reusability, accuracy and precision for the extraction of cocaine from saliva samples. It was observed that V-MMIPs gave higher physical stability than PEG-MMIPs. Thus, V-MMIP were used for the analysis of cocaine users saliva. The developed procedure based on ion mobility spectrometry (IMS) provided limits of detection and quantification o…

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…

Polychlorinated diphenyl ethers, dibenzo-p-dioxins and dibenzofurans in finnish human tissues compared to environmental samples

1995

Finnish human samples from the Helsinki area and Arctic cod samples from Vestertana Fjord (Norway) were analyzed for polychlorinated diphenyl ethers (PCDE) and 2,3,7,8-chloro substituted dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF). The PCDE, PCDD and PCDF contents in human and animal samples from Finland and elsewhere were briefly reviewed. PCDEs were non-detectable in human liver and testis, but some PCDE congeners were identified in human adipose tissue and fat of boiled Arctic cod liver composite. The contents of PCDEs in Finnish human samples were similar to those reported in the literature for human tissues from North America. The estimated concentrations of PCDEs 99, 147 + 153 (…

Urinary levels of enniatin B and its phase I metabolites: First human pilot biomonitoring study

2018

Abstract Enniatins (Enns) are mycotoxins produced by Fusarium spp. and are widely distributed contaminants of cereals and derivate products. Among the different identified enniatins, Enn B is the most relevant analogue in cereals in Europe. Therefore, the aim of this study was to investigate for the first time the occurrence of Enn B and Enn B phase I metabolites in 300 human urine samples throughout an ultrahigh-performance liquid chromatography-high resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) methodology. Three different sample preparation procedures were evaluated and salting-out liquid-liquid extraction showed satisfactory validation results. Enn B was quantified in 83.7% of sa…

Urinary excretion of heptanones, heptanoles and 2,5-heptanedione after controlled acute exposure of volunteers to n-heptane.

2018

A lack of well-established parameters and assessment values currently impairs biomonitoring of n-heptane exposure. Using controlled inhalation experiments, we collected information on urinary n-heptane metabolite concentrations and the time course of metabolite excretion. Relationships between external and internal exposure were analysed to investigate the suitability of selected metabolites to reflect n-heptane uptake. Twenty healthy, non-smoking males (aged 19-38 years, median 25.5) were exposed for 3 h to 167, 333 and 500 ppm n-heptane, each. Spot urine samples of the volunteers, collected before exposure and during the following 24 h, were analysed for heptane-2-one, 3-one, 4-one, 2,5-d…

Mycotoxin Dietary Exposure Assessment through Fruit Juices Consumption in Children and Adult Population

2019

Consumption of fruit juice is becoming trendy for consumers seeking freshness and high vitamin and low caloric intake. Mycotoxigenic moulds may infect fruits during crop growth, harvest, and storage leading to mycotoxin production. Many mycotoxins are resistant to food processing, which make their presence in the final juice product very likely expected. In this way, the presence of 30 mycotoxins including aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2), alternariol (AOH), alternariol monomethyl ether (AME), Ochratoxin A (OTA), fumonisin B1 (FB1), fumonisin B2 (FB2), enniatin A (ENNA), enniatin A1 (ENNA1), enniatin B (ENNB), enniatin B1 (ENNB1), beauverici…

Cumyl-PEGACLONE: A comparatively safe new synthetic cannabinoid receptor agonist entering the NPS market?

2018

Non-contact breath sampling for sensor-based breath analysis

2019

Breath analysis holds great promise for real-time and non-invasive medical diagnosis. Thus, there is a considerable need for simple-in-use and portable analyzers for rapid detection of breath indicators for different diseases in their early stages. Sensor technology meets all of these demands. However, miniaturized breath analyzers require adequate breath sampling methods. In this context, we propose non-contact sampling; namely the collection of breath samples by exhalation from a distance into a miniaturized collector without bringing the mouth into direct contact with the analyzing device. To evaluate this approach different breathing maneuvers have been tested in a real-time regime on a…

In vivo sodium release and saltiness perception in solid lipoprotein matrices. 2. Impact of oral parameters

2012

This study aimed to investigate the relationships between sodium release, saltiness, and oral parameters during the eating of lipoprotein matrices (LPM). Sodium release and saltiness relative to 10 LPM were recorded during normal mastication by five subjects with differing oral parameters (chewing efficiency and salivary flow rate). The LPM samples varied in composition (dry matter, fat, salt, and pH levels) and represented a broad range of hardness. Mastication was recorded using electromyography simultaneously with sensory assessment. Differences in chewing behavior could explain most of the variability in sodium release and saltiness among subjects. Subjects with a higher chewing force a…

Case report: Another death associated to γ-hydroxybutyric acid intoxication

2019

Abstract We report a fatal γ-hydroxybutyric acid (GHB) intoxication of a forty-year old man. According to an acquaintances’ statement, the deceased had drunk a beverage containing GHB approximately five hours before he was found. Postmortem GHB concentrations were determined using gas chromatography coupled to single quadrupole mass spectrometry after simple protein precipitation with methanol and derivatization with BSTFA (1% TMCS). Concentrations in body fluids and tissues of the deceased were as follows: cardiac blood 384 mg/L, femoral blood 358 mg/L, urine 864 mg/L, brain tissue 211 mg/kg, liver tissue 201 mg/kg, kidney tissue 492 mg/kg, bile 334 mg/L and gastric content 2025 mg/L. In a…