[Determination of anions in natural water with low pressure ion chromatography]

An application of low pressure ion chromatography to the analysis of natural water is described. Cl-, NO3- and SO4(2-) in the local tap water, lake, river and rain waters were separated and quantified. The limits of detection for Cl-, NO3- and SO4(2-) were 0.0136, 0.204, and 0.161 mg/L, respectively, and the recoveries were between 90% and 104%. The optimum condition is 1.44 mmol/L of Na2CO3 in eluent at a flow rate of 1.2 mL/min. The conductivity detector was used at 1.4 mu omega-1 and the sample volume injected was 20 microL. Similar chromatographic condition is also suitable for determination of NO2- and SO3(2-) in water samples. Furthermore, the limitations of the eluent composition used is also discussed.