Analysis of Phosphate in Rhizosphere Soil Solution Samples Using Capillary Electrophoresis / 分析化学

ABSTRACT

Analytical method of capillary zone electrophoresis with indirect UV detection was optimized and validated to determine the phosphate in rhizosphere soil solution samples.The effect of detection wavelength, electrolyte composition, separation voltage and temperature were investigated.Analyses were performed in a 56 cm uncoated fused-silica capillary(length to the detector window) with reversed electroosmotic flow, anodic detection in 205 nm, separation voltage-20 kV, and temperature 25 t.The electrolyte contained 32 mmol/L tris-hydroxymethyl-aminomethane, 4 mmol/L 1,2, 4-benzene-tricarboxylic trimellitic acid and 0.3 mmol/L tetradecyl-trimethylammonium bromide, pH 8.5.Under the conditions, the negative effect of the inorganic anion, such as Cl~-, SO_4~(2-) and NO_3~-, can be reduced on phosphate.The detection limit was 0.68 mg/L(S/N=3), and the recovery was 87.2%-99.4%.The method has been applied to the determi nation of the concentration of phosphate in the rhizoshere soil solution.