a novel mixed-mode solid phase extraction coupled with lc–msms for the re-evaluation of free 3-nitrotyrosine in human plasma as an oxidative stress biomarker论文.pdf

Talanta 140 (2015) 45 –51 Contents lists available at ScienceDirect Talanta journal homepage: /locate/talanta A novel mixed-mode solid phase extraction coupled with LC–MS/MS for the re-evaluation of free 3-nitrotyrosine in human plasma as an oxidative stress biomarker Xiaoguang (Sunny) Li a,n, Shu Li a, Gottfried Kellermann a,b a Pharmasan Labs, Inc., 373 280th Street, Osceola, WI 54020, USA b NeuroScience Inc., 373 280th Street, Osceola, WI 54020, USA a r t i c l e i n f o a b s t r a c t Article history: 3-Nitrotyrosine (3-NT) has been widely adopted as a biomarker of oxidative stress. However, an enor- Received 3 December 2014 mous range of reported concentrations of 3-NT in biological matrices indicated an underlying metho- Received in revised form dological problem. Consequently, our understanding of tyrosine nitration in vivo and its significance as a 10 February 2015 biomarker may have been confounded. Here we report a fast, specific and sensitive LC–MS/MS method to Accepted 15 February 2015 Available online 6 March 2015 accurately quantify free 3-NT in human plasma. For the first time, a single-step solid phase extraction of 3-NT using mixed-mode sorbent in a 96-well plate was developed after significant optimization. Com- Keywords: plete chromatographic separation of 3-NT from other tyrosine analogs was achieved on a PFPP column 3-Nitrotyrosine