Analysis of fluoride, chloride, nitrate and sulphate in natural waters using ion chromatography

The analysis of anion components of thirty natural water samples using an ion-chromatographic method were compared to analyses for F, Cl, NO₃ and SO₄ obtained by presently used techniques. Of these thirty samples, five were replicates. Precision estimates were also calculated from synthetic solution replicates. In addition, a comparison of results obtained through separator columns of two different lengths (250 mm and 500 mm) was completed. An inter-anion interference test indicated that, at pH 6, analysis of low concentrations of any one of the four anions studied was not affected by large concentrations of the other three anions. Reported detection limits for the ion-chromatographic technique are one to two orders of magnitude below routine methods. Replicate sample analysis indicated that a relative standard deviation below 1 percent was possible for F, Cl, NO₃ and SO₄.