Determination of 3-nitrotyrosine by micellar electrokinetic chromatography with on-column high-salt stacking

A novel method for the quantification of minor 3-nitrotyrosine (3-NT) in NaNO2-H2O2-hemin-tyrosine system was established by micellar electrokinetic chromatography with on-column high-salt stacking. The optimum CE separation conditions were achieved by using 36 mmol/L of Na2B4O7 as the running buffer containing 30 mmol/L of SDS at pH 9.3, injection time of 30 s at pressure of 3.4 kPa; separation voltage of 20 kV at temperature of 25 degrees C; sample matrix containing 100 mmol/L of NaCl. Under the optimal CE conditions, the linear relationship ranged from 0.78 to 50 mu mol/L (r = 0.9953), and the limit of detection ( LOD) was 0.1 mu mol/L (S/N = 3). The RSDs of migration time for inter- and intra-day were 1.6% and 2.8%, respectively. The recoveries were 95.2% - 103.1% and the RSDs for inter- and intra-day were less than 3 % at various spiked levels. In this study, useful method is provided for the directly analysis of minor 3-NT in biological samples. The method is simple, rapid and sensitive.