Quantitation of isoprostane isomers in human urine from smokers and nonsmokers by LC-MS/MS

Abstract

A simple, rapid liquid chromatography-tandem mass spectrometry method was developed to identify and quantitate in human urine the isoprostanes iPF 2a -III, 15-epiiPF 2a -III, iPF 2a -VI, and 8,12-iso-iPF 2a -VI along with the prostaglandin PGF 2a and 2,3-dinor-iPF 2a -III, a metabolite of iPF 2a -III. Assay specificity, linearity, precision, and accuracy met the required criteria for most analytes. The urine sample storage stability and standard solution stability were also tested.The methodology was applied to analyze 24 h urine samples collected from smokers and nonsmokers on controlled diets. The results for iPF 2a -III obtained by our method were significantly correlated with results by an ELISA, although an ?2-fold high bias was observed for the ELISA data. For iPF 2a -III and its metabolite 2,3-dinoriPF 2a -III, smokers had significantly higher concentrations than nonsmokers (513 6 275 vs. 294 6 104 pg/mg creatinine; 3,030 6 1,546 vs. 2,046 6 836 pg/mg creatinine, respectively). The concentration of iPF 2a -VI tended to be higher in smokers than in nonsmokers; however, the increase was not statistically significant in this sample set. Concentrations of the other three isoprostane isomers showed no trends toward differences between smokers and nonsmokers. Among smokers, the daily output of two type VI isoprostanes showed a weak correlation with the amount of tobacco smoke exposure, as determined by urinary excretion of total nicotine equivalents.-Yan, W., G. D. Byrd, and M. W. Ogden. Quantitation of isoprostane isomers in human urine from smokers and nonsmokers by LC-MS/MS.

A simple and robust UPLC-SRM/MS method to quantify urinary eicosanoids

“…We found that metabolite levels determined with our novel UPLC-SRM/MS method generally were in good agreement with concentration ranges determined by other groups ( 16,24,33,34,36,42 ). Tetranor PGE-M, both PGF 2 ␣ metabolites, and 2,3-dinor-TXB 2 levels were signifi cantly elevated in urine samples of smokers ( Table 7 ).…”

“…To extract all analytes of interest with one common sample preparation approach, different extraction procedures ( 29,31,(36)(37)(38)(39). Therefore, we tested sample preparation using C18 RP SPE and polymeric RP SPE.…”

Assessment of 8-isoprostane (8-isoPGF2α) in Urine of Non-Small Cell Lung Cancer (NSCLC) Patients Undergoing Chemotherapy

“…Cayman affinity column 416358), particularly if good correlation with GC-MS results is desired (Davies et al, 2006;Yan et al, 2007;Zhang & Saku, 2007), there would seem to be no specific requirement for urine samples with immunoassay methods. Immunoassays have been generally demonstrated to work very well in buffer systems that do not contain large amounts of biological substances.…”

A comparison of methods for the measurement of 8-isoPGF2α: a marker of oxidative stress

“…The HPLC mobile phase used (0.15% NH 4 OH/water [v/v] and 0.15% NH 4 OH in 95:5 acetonitrile:methanol) was selected on the basis of increased sensitivity of detection, in which NH 4 OH buffers were superior to buffers with ammonium acetate or formic acid. 11 Sample preparation and HPLC separation is an important step in the measurement of 8-iso-PGF 2a as it is one of a group of isobaric F2-isoprostane stereoisomers, which all have the same transition in mass spectrometry (m/z 353/ 193). There are two main approaches used for sample preparation: SPE or IAC.…”

“…7 LC/MS/MS offers advantages over GC/MS in that sample preparation is less extensive and 8-iso-PGF 2a can be separated from interfering F2-isoprostane isomers by HPLC. 11,12,16 ELISA has been suggested to be a useful method for quantification of 8-iso-PGF 2a . However, selectivity for 8-iso-PGF 2a is not as good by ELISA unless IAC or SPE sample preparation is used, which comprises the advantages of high throughput offered by ELISA.…”