ANALYSIS OF NITRATE IN BIOLOGICAL-FLUIDS BY CAPILLARY ELECTROPHORESIS

Nitrite and nitrate represent the products of the final pathway of nit ric oxide metabolism. These two ions were analyzed by capillary electr ophoresis (CE) in serum, cerebrospinal fluid, urine and tissue homogen ates by mixing the sample with acetonitrile containing NaBr as an inte rnal standard, followed by centrifugation. The supernatant was injecte d hydrodynamically on a capillary 50 cm X 75 mu m (I.D.) and electroph oresed at 6 kV (reversed polarity) in 1.4% sodium chloride in phosphat e buffer for 13 min with detection at 214 nm. In addition to removal o f the proteins, acetonitrile caused sample stacking. Urinary nitrate a nalysis by CE was compared to that by the enzymatic Aspergillus nitrat e reductase method, with a correlation coefficient of 0.96. (C) 1997 E lsevier Science B.V.