scholarly journals Rapid Liquid Chromatography—Tandem Mass Spectrometry Analysis of Two Urinary Oxidative Stress Biomarkers: 8-oxodG and 8-isoprostane

Antioxidants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 38
Author(s):  
Nicolas Sambiagio ◽  
Jean-Jacques Sauvain ◽  
Aurélie Berthet ◽  
Reto Auer ◽  
Anna Schoeni ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mass Spectrometry ◽  
Acetic Acid ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Matrix Effects ◽  
Mass Spectrometry Analysis ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

Human biomonitoring of oxidative stress relies on urinary effect biomarkers such as 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG), and 8-iso-prostaglandin F2α (8-isoprostane); however, their levels reported for similar populations are inconsistent in the scientific literature. One of the reasons is the multitude of analytical methods with varying degrees of selectivity used to quantify these biomarkers. Single-analyte methods are often used, requiring multiple injections that increase both time and cost. We developed a rapid ultra-high-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) method to quantify both urinary biomarkers simultaneously. A reversed-phase column using a gradient consisting of 0.1% acetic acid in water and 0.1% acetic acid in methanol/acetonitrile (70:30) was used for separation. The MS detection was by positive (8-oxodG) and negative (8-isoprostane) ion-mode by multiple reaction monitoring. Very low limit of detection (<20 pg/mL), excellent linearity (R2 > 0.999), accuracy (near 100%), and precision (CV < 10%) both for intra-day and inter-day experiments were achieved, as well as high recovery rates (>91%). Matrix effects were observed but were compensated by using internal standards. Our newly developed method is applicable for biomonitoring studies as well as large epidemiological studies investigating the effect of oxidative damage, as it requires only minimal clean up using solid phase extraction.

scholarly journals Isotope-Dilution Liquid Chromatography–Tandem Mass Spectrometry Candidate Reference Method for Total Testosterone in Human Serum

2013 ◽  
Vol 59 (2) ◽  
pp. 372-380 ◽  
Author(s):  
Julianne Cook Botelho ◽  
Christopher Shacklady ◽  
Hans C Cooper ◽  
Susan S-C Tai ◽  
Katleen Van Uytfanghe ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Isotope Dilution ◽  
Matrix Effects ◽  
Reference Method ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Deming Regression ◽  
Liquid Chromatography Tandem Mass

BACKGROUND We developed and evaluated a candidate reference measurement procedure (RMP) to standardize testosterone measurements, provide highly accurate and precise value assignments for the CDC Hormone Standardization Program, and ensure accurate and comparable results across testing systems and laboratories. METHODS After 2 liquid/liquid extractions of serum with a combination of ethyl acetate and hexane, we quantified testosterone by isotope-dilution liquid chromatography–tandem mass spectrometry with electrospray ionization in the positive ion mode monitoring 289→97 m/z (testosterone) and 292→112 m/z (3C13 testosterone). We used calibrator bracketing and gravimetric measurements to give higher specificity and accuracy to serum value assignments. The candidate RMP was evaluated for accuracy by use of NIST-certified reference material SRM971 and validated by split-sample comparison to established RMPs. We evaluated intraassay and interassay imprecision, measurement uncertainty, potential interferences, and matrix effects. RESULTS A weighted Deming regression comparison of the candidate RMP to established RMPs showed agreement with no statistical difference (slope 0.99, 95% CI 0.98–1.00, intercept 0.54, 95% CI −1.24 to 2.32) and a bias of ≤0.3% for NIST SRM971. The candidate RMP gave maximum intraassay, interassay, and total percent CVs of 1.5%, 1.4%, and 1.7% across the concentrations of testosterone typically found in healthy men and women. We tested structural analogs of testosterone and 125 serum samples and found no interferences with the measurement. CONCLUSIONS This RMP for testosterone can serve as a higher-order standard for measurement traceability and can be used to provide an accuracy base to which routine methods can be compared in the CDC Hormone Standardization Program.

scholarly journals Optimization and validation of a highly sensitive method for determining glyphosate in human urine by solid-phase extraction and liquid chromatography with tandem mass spectrometry: a methodological study

2020 ◽  
Vol 25 (1) ◽  
Author(s):  
Hiroshi Nomura ◽  
Risa Hamada ◽  
Isao Saito ◽  
Kunihiko Nakane ◽  
Ritsuko Sawa ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Mass Spectrometry Analysis ◽  
Tandem Mass ◽  
Phase Extraction ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

Abstract Background Glyphosate and its salt formulations are nonselective herbicides that have been extensively used worldwide, both for residential and agricultural purposes. The possible carcinogenicity and teratogenicity of glyphosate remain to be elucidated. We developed a sensitive and high-throughput analytical method for urinary glyphosate using liquid chromatography-tandem mass spectrometry with the aim of contributing to glyphosate exposure assessment in epidemiological studies. Methods After urine dilution (creatinine matching dilution to 0.05 g creatinine/L), glyphosate was extracted using two types of solid phase extraction columns (SCX and NH2) with automated sample preparation instruments. The eluate was dried and dissolved in the mobile phase, followed by liquid chromatography-tandem mass spectrometry analysis. The optimized method was applied to urine samples obtained from 54 Japanese adults and children. Results The results from the validation study demonstrated good recoveries (91.0-99.6%), within- and between-run precisions (< 15%), low detection limits (0.1 μg/L), and lower limit of quantification (0.3 μg/L). The detection frequency and median concentration of the urinary glyphosate in Japanese subjects were 59% and 0.25 μg/L (0.34 μg/g creatinine). Conclusions Our reliable determination method was successful in measuring urinary glyphosate concentration. Moreover, this is the first biomonitoring report of urinary glyphosate levels in the Japanese general population.

Simultaneous Determination of Isopyrazam and Azoxystrobin in Cucumbers by Liquid Chromatography–Tandem Mass Spectrometry

2017 ◽  
Vol 80 (12) ◽  
pp. 2112-2118 ◽  
Author(s):  
Dan Hu ◽  
Xu Xu ◽  
Tian Cai ◽  
Wei-Ying Wang ◽  
Chun-Jie Wu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Matrix Effects ◽  
Fast Method ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Relative Standard ◽  
Liquid Chromatography Tandem Mass

ABSTRACTA rapid and sensitive analytical method based on high-performance liquid chromatography–tandem mass spectrometry was developed and validated for the determination of isopyrazam (IZM) and azoxystrobin (AZT) in cucumbers. A modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was used as the pretreatment procedure. The samples were extracted with acetonitrile and cleaned up with octadecylsilyl silica (C18) and graphite carbon black. The proposed method resulted in satisfactory recovery of IZM and AZT (91.48 to 114.62%), and relative standard deviations were less than 13.1% at fortification concentrations of 1, 20, and 500 μg kg−1 (n = 3). The limits of quantification for IZM and AZT were 0.498 and 0.499 μg kg−1, respectively, which are far below the maximum residue level (0.5 mg kg−1) established for this type of sample. Matrix effects were also evaluated. This study established a sensitive and fast method for the detection of IZM and AZT in cucumber samples.

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