Optimization of an Alternative Methodology for Simultaneous Analysis of Nitrite and Nitrate in Water from Urban Stream by Capillary Electrophoresis under Direct UV Detection

Abstract

An alternative methodology for simultaneous determination of nitrite and nitrate by capillary zone electrophoresis using direct detection UV at 210 nm under reverse electrosmotic flow is proposed. The choice of the electrolyte composition has taken account: the mobility of the anion buffer and of the solutes; the low absorbance of the buffer in 210 nm; high base line stability and analysis time. The electrolyte optimized has consisted of 100 mmol.L–1 TRIS/HCl buffer and 0.15 mmol.L–1 CTAB at pH 8.2. The proposed method was applied successfully in the analysis of nitrite and nitrate in samples from urban stream in the absence of usual sample pretreatment.