Highly Selective Simultaneous Determination of Eight Inorganic Anions in Drinking Water by Single Column High Pressure Anion Chromatography

Ion Chromatography is a well-established analytical technique for the simultaneous determination of ions. This paper focuses on the analytical determination of eight inorganic anions: fluoride, hydrogen carbonate, chloride, nitrite, bromide, nitrate, hydrogen phosphate and sulphate, using conductometric detection. The separation of the cited anions was achieved on a low capacity anion exchange column Hamilton PRP-X100 100 × 4.1 mm, 10 μm, with a mobile phase consisted of 2.5 mM p-hydroxybezoic acid and 2.0 mM sodium benzoate at a pH 9.0 adjusted with 1N NaOH and 8% Ch3OH as organic modifier, at a flow rate 0.7 ml/min. For the quantitative determination bromide was used as internal standard at a concentration of 7.8 mg/l. A rectilinear relationship was observed up to 40 mg/l for all ions except for carbonate that was up to 30 mg/l. The detection limits (S/N = 3) were 100 μg/l for carbonate and 50 μg/l for the rest of the cited anions, when 50 μ/l of the samples were injected onto the analytical column. Recovery of anions in spiked samples ranged from 90.44% to 108.88% with the time of analysis being less than 10 min. The statistical evaluation of the method was examined performing intra-day (n=8) and inter-day calibration (n=10) and found to be satisfactory with high accuracy and precision results. The applicability of the method was demonstrated on the analysis of drinking water: tap, table and mineral.