scholarly journals Large Differences in Urinary Benzene Metabolite S-Phenylmercapturic Acid Quantitation: A Comparison of Five LC–MS-MS Methods

2020 ◽  
Author(s):  
Denise S Tevis ◽  
Andrew Willmore ◽  
Deepak Bhandari ◽  
Brett Bowman ◽  
Chloe Biren ◽  
...  
Keyword(s):  
Human Urine ◽  
Analytical Methods ◽  
Urine Samples ◽  
Genotoxic Carcinogen ◽  
Human Urine Samples ◽  
Ph Values ◽  
Wide Range ◽  
Acidic Conditions ◽  
Hematological Abnormalities ◽  
Reference Samples

Abstract Benzene is a known genotoxic carcinogen linked to many hematological abnormalities. S-phenylmercapturic acid (PHMA, N-acetyl-S-(phenyl)-L-cysteine, CAS# 4775-80-8) is a urinary metabolite of benzene and is used as a biomarker to assess benzene exposure. Pre-S-phenylmercapturic acid (pre-PHMA) is a PHMA precursor that dehydrates to PHMA at acidic pH. Published analytical methods that measure urinary PHMA adjust urine samples to a wide range of pH values using several types of acid, potentially leading to highly variable results depending on the concentration of pre-PHMA in a sample. Information is lacking on the variation in sample preparation among laboratories regularly measuring PHMA and the effect of those differences on PHMA quantitation in human urine samples. To investigate the differences in PHMA quantitation, we conducted an inter-laboratory comparison that included the analysis of 50 anonymous human urine samples (25 self-identified smokers and 25 self-identified non-smokers), quality control samples and commercially available reference samples in five laboratories using different analytical methods. Observed urinary PHMA concentrations were proportionally higher at lower pH, and results for anonymous urine samples varied widely among the methods. The method with the neutral preparation pH yielded results about 60% lower than the method using the most acidic conditions. Samples spiked with PHMA showed little variation, suggesting that the variability in results in human urine samples across methods is driven by the acid-mediated conversion of pre-PHMA to PHMA.

scholarly journals High-Throughput Determination of Major Mycotoxins with Human Health Concerns in Urine by LC-Q TOF MS and Its Application to an Exposure Study

Toxins ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 42
Author(s):  
Noelia Pallarés ◽  
Dionisia Carballo ◽  
Emilia Ferrer ◽  
Yelko Rodríguez-Carrasco ◽  
Houda Berrada
Keyword(s):  
Risk Assessment ◽  
Human Urine ◽  
Solid Phase ◽  
Human Biomonitoring ◽  
Urine Samples ◽  
Food Contaminants ◽  
Potential Health ◽  
Human Urine Samples ◽  
Wide Range

Human biomonitoring constitutes a suitable tool to assess exposure to toxins overcoming the disadvantages of traditional methods. Urine constitutes an accessible biological matrix in biomonitoring studies. Mycotoxins are secondary metabolites produced naturally by filamentous fungi that produce a wide range of adverse health effects. Thus, the determination of urinary mycotoxin levels is a useful tool for assessing the individual exposure to these food contaminants. In this study, a suitable methodology has been developed to evaluate the presence of aflatoxin B2 (AFB2), aflatoxin (AFG2), ochratoxin A (OTA), ochratoxin B (OTB), zearalenone (ZEA), and α-zearalenol (α-ZOL) in urine samples as exposure biomarkers. For this purpose, different extraction procedures, namely, the Solid Phase Extraction (SPE); Dispersive Liquid–Liquid Microextraction (DLLME); and Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) methods were assessed, followed by Liquid Chromatography coupled to Quadrupole Time of Flight Mass Spectrometry with Electrospray Ionization (LC-ESI-QTOF-MS) determination. Then, the proposed methodology was applied to determine mycotoxin concentrations in 56 human urine samples from volunteers and to estimate the potential risk of exposure. The results obtained revealed that 55% of human urine samples analyzed resulted positive for at least one mycotoxin. Among all studied mycotoxins, only AFB2, AFG2, and OTB were detected with incidences of 32, 41, and 9%, respectively, and levels in the range from <LOQ to 69.42 µg/L. Risk assessment revealed a potential health risk, obtaining MoE values < 10,000. However, it should be highlighted that few samples were contaminated, and that more data about mycotoxin excretion rates and their BMDL10 values are needed for a more accurate risk assessment.

scholarly journals Stanozolol‐ N ‐glucuronide metabolites in human urine samples as suitable targets in terms of routine anti‐doping analysis

2021 ◽  
Author(s):  
Lorenz Göschl ◽  
Günter Gmeiner ◽  
Peter Gärtner ◽  
Georg Stadler ◽  
Valentin Enev ◽  
...  
Keyword(s):  
Human Urine ◽  
Urine Samples ◽  
Doping Analysis ◽  
Human Urine Samples

scholarly journals The colorimetric and microfluidic paper-based detection of cysteine and homocysteine using 1,5-diphenylcarbazide-capped silver nanoparticles

RSC Advances ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 3295-3303 ◽  
Author(s):  
Sattar Shariati ◽  
Gholamreza Khayatian
Keyword(s):  
Silver Nanoparticles ◽  
Human Urine ◽  
Quantitative Measurement ◽  
Urine Samples ◽  
Human Urine Samples

A simple and novel portable method for the quantitative measurement of cysteine and homocysteine in human urine samples is presented.

scholarly journals Analytical and physiological validation of an enzyme immunoassay to measure oxytocin in dog, wolf, and human urine samples

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
G. Wirobski ◽  
F. S. Schaebs ◽  
F. Range ◽  
S. Marshall-Pescini ◽  
T. Deschner
Keyword(s):  
Enzyme Immunoassay ◽  
Human Urine ◽  
Extraction Efficiency ◽  
Urine Samples ◽  
Antibody Specificity ◽  
Analytical Validation ◽  
Human Urine Samples ◽  
Assay Performance ◽  
Fit For Purpose ◽  
Commercial Enzyme Immunoassay

AbstractOxytocin (OT) promotes pro-sociality, bonding, and cooperation in a variety of species. Measuring oxytocin metabolite (OTM) concentrations in urine or saliva provides intriguing opportunities to study human and animal behaviour with minimal disturbance. However, a thorough validation of analytical methods and an assessment of the physiological significance of these measures are essential. We conducted an analytical validation of a commercial Enzyme Immunoassay (EIA; Arbor OT assay kit) to measure OTM concentrations in dog, wolf, and human urine samples. To test the assay’s ability to detect changes in OTM concentrations, we administered oxytocin intranasally to 14 dogs. Assay performance with regard to parallelism was acceptable. Assay accuracy and extraction efficiency for dog and wolf samples were comparable to a previously validated assay (Enzo OT assay kit) but variation was smaller for human samples. Binding sensitivity and antibody specificity were better in the Arbor assay. Average OTM concentrations were more than twice as high as in comparable samples measured with the Enzo assay, highlighting a lack of comparability of absolute values between different assays. Changes in OTM concentrations after intranasal treatment were detected reliably. The Arbor assay met requirements of a “fit-for-purpose” validation with improvement of several parameters compared to the Enzo assay.

CE-ESI-MS coupled with dynamic pH junction online concentration for analysis of peptides in human urine samples

2010 ◽  
Vol 31 (20) ◽  
pp. 3400-3406 ◽  
Author(s):  
Hongzhi Ye ◽  
Shifei Xia ◽  
Wei Lin ◽  
Lishuang Yu ◽  
Xueqin Xu ◽  
...  
Keyword(s):  
Human Urine ◽  
Urine Samples ◽  
Human Urine Samples ◽  
Esi Ms ◽  
Dynamic Ph Junction
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