Modified method for the determination of capillary electrophoresis nitric oxide-correlated nitrate in tissue homogenates

A modified capillary electrophoretic method for the determination of nitric oxide correlated nitrate in several tissue homogenates is described in thi s study. The method was developed using a running buffer consisting of 200 mM lithium chloride and 10 mM berate buffer at pH 8.5, in a fused-silica co lumn total 82 cm, effective 43 cm length and 75 mum I.D. The signal was mea sured at 214 nm and controlled current of 200 muA (equivalent to 12.7 kV) w as applied in the reversed polarity direction. The sample was injected by v acuum pressure 50 ms (25 nl). In these conditions, bromide as internal stan dard and nitrate appeared at 7.2 and 8.9 min, respectively. Whole validatio n procedures were applied and satisfactory results were obtained. The nitra te levels of the tissue homogenates of control and L-NAME applied (heart, b rain, kidney, stomach, lung, testis and liver) were monitored by the presen t method and it was decided that the method is precise and accurate. (C) 20 01 Elsevier Science B.V. All rights reserved.