Fast analysis of water samples for detection of anions by capillary zone electrophoresis

A capillary zone electrophoresis (CZE) method with relatively low separatio n voltage and short capillary length, using indirect UV detection was devel oped for the fast and quantitative determination of Cl-, NO2-, SO42-, NO3- F- and HCO-in potable water samples. Baseline separation of inorganic and o rganic anions was achieved within I min. The optimal carrier electrolyte co nsisted of 6.0 mM sodium chromate, 2.5 mM CTAB and 3.5% acetonitrile at pH 9.0. The effects of pH and the concentrations of electrolyte and flow modif iers on the resolution were investigated. Two injection methods, gravity an d electrokinetic, were compared. The application of electrokinetic injectio n, using pyroglutamic acid as an internal standard was found to provide a m ethod that is fast, sensitive and quantitative, with an R.S.D. for migratio n times from 0.1% to 0.3% and for peak areas from 1.8% to 4.1%. The limits of detection were 0.08 mg/L Cl-, 0.3 mg/L NO2-, 0.1 mg/L SO42-, 0.1 mg/L NO 3-, 0.07 mg/L F-, and 0.3 mg/L HCO3-. This method has been successfully app lied to determine SO42- Cl-, NO2- SO42-, NO3- F-, HCO3- in municipal water, surface water and bottled water samples.