Search results for "CHROMATOGRAPHY"
showing 10 items of 5037 documents
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…
Internal exposure of the general population to DEHP and other phthalates--determination of secondary and primary phthalate monoester metabolites in u…
2003
A number of phthalates and their metabolites are suspected of having teratogenic and endocrine disrupting effects. Especially the developmental and reproductive effects of di(2-ethylhexyl)phthalate (DEHP) are under scrutiny. In this study we determined the concentrations of the secondary, chain oxidized monoester metabolites of DEHP, mono(2-ethyl-5-hydroxyhexyl)phthalate (5OH-MEHP) and mono(2-ethyl-5-oxo-hexyl)phthalate (5oxo-MEHP) in urine samples from the general population. The utilization of the secondary metabolites minimized any risk of contamination by the ubiquitously present phthalate parent compounds. Included in the method were also the simple monoester metabolites of DEHP, dioct…
Mycotoxin Occurrence and Risk Assessment in Gluten-Free Pasta through UHPLC-Q-Exactive Orbitrap MS
2021
Celiac disease (CD) is a genetic-based autoimmune disorder which is characterized by inflammation in the small intestinal mucosa due to the intolerance to gluten. Celiac people should consume products without gluten, which are elaborated mainly with maize or other cereals. Contamination of cereals with mycotoxins, such as fumonisins (FBs) and aflatoxins (AFs) is frequently reported worldwide. Therefore, food ingestion is the main source of mycotoxin exposure. A new analytical method was developed and validated for simultaneous analysis of 21 mycotoxins in gluten-free pasta, commonly consumed by celiac population as an alternative to conventional pasta. Ultrahigh-performance liquid chromatog…
Association between reduced lymphocyte beta-adrenergic receptors and left ventricular dysfunction in young obese subjects
1994
This study was designed to evaluate total (t) and surface (s) beta-adrenergic receptors (BAR) density and their relationships with left ventricular function in young obese subjects. BAR density, plasma insulin, catecholamines and left ventricular function were evaluated in 27 young obese subjects (BMI30.5 kg/m2 for males and27.3 kg/m2 for females) without other risk factors for cardiovascular diseases (smoking, hypertension, diabetes and lipid abnormalities) and in 20 lean controls (BMI25 kg/m2 for males and24.7 kg/m2 for females). Both groups were matched for gender, age and body height. BAR density was evaluated according to Böyum and De Blasi methods. Plasma catecholamines by high perfus…
Busulfan systemic exposure after oral administration of extemporeanously prepared high-dose busulfan capsules.
2009
Purpose. The aim of the study was to analyze patients’ busulfan (BU) exposure after oral administration of extemporeanously prepared BU capsules prior to blood stem cell transplantation. Methods. Patients were treated with 1 mg/kg body weight BU administered orally every 6h on each of 4 consecutive days prior to blood stem cell transplantation. Each BU dose was administered in 1 gelatine capsule to be swallowed and containing the individually calculated dose of pure BU active substance. Blood samples were obtained from 6 adult patients 0, 30, 60, 90, 120, 180, 240, 300, and 360 min after the 1st, 5th, and 13th BU dose, frozen and analyzed subsequently by using a HPLC assay with UV detectio…
Direct measurement of cell-free DNA from serially collected capillary plasma during incremental exercise
2014
To investigate the kinetics of cell-free DNA (cfDNA) due to exercise, we established a direct real-time PCR for the quantification of cfDNA from unpurified capillary plasma by amplification of a 90- and a 222-bp multilocus L1PA2 sequence. Twenty-six male athletes performed an incremental treadmill test. For cfDNA measurement, capillary samples were collected serially from the fingertip preexercise, during, and several times postexercise. Venous blood was drawn before and immediately after exercise to compare capillary and venous cfDNA values. To elucidate the strongest association of cfDNA accumulations with either cardiorespiratory or metabolic function during exercise, capillary cfDNA val…
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…
Quantification of the Fabry marker lysoGb3 in human plasma by tandem mass spectrometry
2011
Morbus Fabry is a hereditary metabolic disorder with low prevalence and late clinical manifestation. A defect in the α-galactosidase gene leads to lysosomal accumulation of the glycolipid globotriaosylceramide (Gb3). Gb3 may be used for monitoring of enzyme replacement therapy (ERT), but diagnostic sensitivity is limited. Recently, globotriaosylsphingosine (lysoGb3) was introduced as a promising new marker with significantly better sensitivity. For Fabry diagnosis, clinical studies and possible therapy monitoring, we established a fast and reliable LC-MS/MS assay for quantification of lysoGb3 in human plasma. Protein precipitation and glycolipid extraction from EDTA plasma was performed usi…
An experimental model for the exposure of human ciliated cells to sulfur dioxide at different concentrations
1994
Mucociliary transport is an important nonimmunological defense mechanism of the respiratory tract. The aim of this study was to investigate the effect of sulfur dioxide (SO2) at different concentrations on ciliary beat frequency (CBF). Ciliated cells were obtained from 12 volunteers by nose brush. CBF was quantified using video-interference microscopy. The cells were placed on a polycarbonate membrane in contact with the surface of a reservoir filled with RPMI 1640 (bicarbonate buffered) or Ringer's (electrolyte) solution, allowing the cells to be supplied by capillarity. In an exposure chamber the cells were exposed for 30 min to SO2 2.5-12.5 ppm at 37 degrees C and 100% air humidity. SO2 …