New Procedure for the Determination of 3-Nitrotyrosine in Plasma by GC\u2013ECD

A method suitable for the determination of 3-nitrotyrosine, a well known marker of nitro-oxidative stress, in plasma by GC-ECD has been investigated. After deproteinisation, SPE and LC separation, 3-nitrotyrosine was derivatised by a single-step procedure to the corresponding N-heptafluorobutyryl heptafluorobutyl ester and analysed. The precision and reliability of the procedure were assured by using 4-nitrophenylalanine as internal standard and a diverter valve to protect the detector. The method was applied to the analysis of volunteers' plasma samples