Morcos E, Wiklund N P
Department of Urology, Karolinska Hospital, Stockholm, Sweden.
Electrophoresis. 2001 Aug;22(13):2763-8. doi: 10.1002/1522-2683(200108)22:13<2763::AID-ELPS2763>3.0.CO;2-G.
Nitrite and nitrate have been widely used as markers for nitric oxide (NO) formation in vivo and represent the major NO oxidation products in biological fluids. In the present study, the use of capillary electrophoresis (CE) in the measurement of nitrite and nitrate in human urine is described. Urine samples were electrophoresed in an extended light path fused-silica capillary (104 cm; 75 microm ID) at an applied negative potential of 30 kV, and UV detection at 214 nm. Using electrokinetic sample injection (-6 kV x 20 s), we found that urine concentration, pH, sodium and chloride interfered with nitrite and nitrate detection. The detection of nitrite and nitrate was decreased when hydrodynamic sample injection was used (30 mbar x 60 s). However, basal levels of urinary nitrite (0.25 +/- 0.05 microM) and nitrate (591 +/- 115 microM) were detected and no interference by variations in urine concentration and pH was noted when hydrodynamic sample injection was used. Thus, hydrodynamic sample injection is convenient for the measurement of urinary nitrite and nitrate and avoids the effect of variations in urine matrices and pH on nitrite and nitrate detection.
亚硝酸盐和硝酸盐已被广泛用作体内一氧化氮（NO）生成的标志物，并且是生物体液中主要的NO氧化产物。在本研究中，描述了使用毛细管电泳（CE）测量人尿液中的亚硝酸盐和硝酸盐。尿液样本在延长光程熔融石英毛细管（104 cm；内径75μm）中进行电泳，施加负电位30 kV，并在214 nm处进行紫外检测。使用电动进样（-6 kV×20 s）时，我们发现尿液浓度、pH值、钠和氯会干扰亚硝酸盐和硝酸盐的检测。使用液压进样（30 mbar×60 s）时，亚硝酸盐和硝酸盐的检测量会降低。然而，使用液压进样时，检测到尿液中亚硝酸盐的基础水平为（0.25±0.05 microM），硝酸盐的基础水平为（591±115 microM），并且未发现尿液浓度和pH值变化产生的干扰。因此，液压进样便于测量尿液中的亚硝酸盐和硝酸盐，并且避免了尿液基质和pH值变化对亚硝酸盐和硝酸盐检测的影响。
