Simple and rapid method for the measurement of nitrite and nitrate in human plasma and cerebrospinal fluid by capillary electrophoresis

• Published in: Journal of chromatography. B, Biomedical sciences and applications Vol. 727; no. 1; pp. 73 - 79
• Main Authors: ZUNIC, G, SPASIC, S, JELIC-IVANOVIC, Z
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 30.04.1999; Elsevier Science
• Subjects: Analytical, structural and metabolic biochemistry; Biological and medical sciences; Calibration; Electrophoresis, Capillary - methods; Fundamental and applied biological sciences. Psychology; Humans; Inorganic compounds; Nitrate; Nitrates - analysis; Nitrates - blood; Nitrates - cerebrospinal fluid; Nitrite; Nitrites - analysis; Nitrites - blood; Nitrites - cerebrospinal fluid; Other biological molecules; Reproducibility of Results; Sensitivity and Specificity; Spectrophotometry, Ultraviolet; Nitrate; Nitrite; Human; Plasma; Capillary electrophoresis; Nitrites; Analytical method; Nitrates; Cerebrospinal fluid
• ISSN: 0378-4347; 1387-2273
• DOI: 10.1016/S0378-4347(99)00054-7

Nitrite and nitrate levels in physiological fluids are commonly used as an index of nitric oxide production. We developed simple and rapid method for the determination of these anions by capillary zone electrophoresis employing borate buffer (pH 10, 100 mmol/l) as running electrolyte. The anions were analyzed in plasma and cerebrospinal fluid (CSF) without deproteinization of the samples. Electrophoresis was carried out in a capillary (36.5 cm×75 μm) at a potential of 15 kV, with on-column UV detection at 214 nm. Mean retention times for nitrite and nitrates were 4.631 and 5.152 min, respectively. The method was linear ( r=0.999) within a 1–500 μmol/l concentration range. Physiological levels of nitrate in plasma (40.2 μmol/l) and CSF (15.3 μmol/l) could be determined with good precision (coefficients of variation <6%) and accuracy (recoveries of added nitrate to plasma and CSF were 97.4 and 104.5%, respectively). Measurements of the physiological levels of nitrite in plasma (6.1 μmol/l) and CSF (0.9 μmol/l) were less precise and accurate.