Use of capillary electrophoresis with conductivity detection to anions

Capillary electrophoresis with conductivity detection was used to separate and detect chloride (Cl-), nitrate (NO3-), bicarbonate (HCO3-) and dihydric phosphate (H2PO4-) ions. The proposed method was carried out by using citric acid and sodium citrate as buffer solution, under the condition of a-10 kV high voltage power supply. The effects of various buffers, concentrations, pH values and running voltages on separation were investigated. Under the chosen conditions the linear ranges of Cl-, NO3-, HCO3-, and H2PO4- were 5.0 x 10(-5) mol/L -2.5 x 10(-3) mol/L, 6.0 x 10(-5) mol/L-2.0 x 10(-3) mol/L, 5.0 x 10(-6) mol/L-2.0 x 10(-4) mol/L and 6.0 x 10(-5) mol/L-1.0 x 10(-3) mol/L respectively. The detection limits were 1.5 x 10(-5) mol/L, 3.0 x 10(-5) mol/L, 1.0 x 10(-6) mol/L, 2.0 x 10(-5) mol/L and the relative standard deviations (RSD) of migration time were 3.1%, 3.3%, 2.6% and 2.9% respectively. Tap water was analyzed under the same conditions.