A rapid LC-FTMS method for the analysis of cysteine, cystine and cysteine/cystine steady-state redox potential in human plasma

• Published in: Clinica chimica acta Vol. 396; no. 1; pp. 43 - 48
• Main Authors: Johnson, Jennifer M., Strobel, Fredrick H., Reed, Matthew, Pohl, Jan, Jones, Dean P.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.2008
• Subjects: Cysteine; Cystine; Cystine - blood; Cystine - chemistry; Dansyl Compounds; Disulfides - blood; Disulfides - chemistry; Female; FTMS; Human plasma; Humans; Male; Mass Spectrometry - methods; Oxidation-Reduction; Oxidative Stress; Redox; Reproducibility of Results; Spectrometry, Fluorescence; Time Factors; GSSG; Oxidative stress; Cysteine; LC-FTMS; Human plasma; Redox; Cystine; FTMS; CySS; CySSG; Cys; CM-Cys; GSH; CM-GSH
• ISSN: 0009-8981; 1873-3492
• DOI: 10.1016/j.cca.2008.06.020

The steady-state redox potential of the cysteine/cystine couple in human plasma provides a measure of oxidative stress, yet available assays are limited by either specificity or speed of assay. The present study evaluated the use of LC-FTMS for identification based on accurate mass combined with quantification by stable isotopic dilution to rapidly determine cysteine and cystine concentration and cysteine/cystine steady-state redox potential in human plasma. A simple extraction procedure followed by a rapid LC separation eluted cysteine in 4 min and cystine in 1.5 min with simultaneous measurement of glutathione (GSH) and glutathione disulfide (GSSG). A study of five young (mean age = 25.7) subjects and 5 older (mean age = 67.8 y) subjects showed an increased oxidation with age. The analysis by LC-FTMS is suitable for high-throughput analysis of plasma cysteine, cystine and cysteine/cystine steady-state redox potential as clinical measures of oxidative stress.