Fast Analysis of Inorganic Anions by Ion-interaction Chromatography Using a Monolithic Column

An investigation on fast analysis of inorganic anions by ion-interaction chromatography using a silica-based monolithic column and direct conductivity detection was carried out.Tetrabutylammonium hydroxide(TBA-OH)-phthalic acid was used as an eluent.The effects of eluent concentration,eluent pH and flow rate on anions retention time were discussed.When the eluent flow rate was 6 mL/min,using 1.5 mmol/L TBA-OH and 1.1 mmol/L phthalic acid as the eluent(pH 5.5),excellent simultaneous separation and determination of seven inorganic anions (Cl-,NO-2,Br-,NO-3,ClO-3,SO2-4 and I-) were achieved just in 1 min.Detection limits(S/N=3) for inorganic anions were obtained in the range of 0.3~1.9 mg/L.Relative standard deviations based on chromatographic peak areas and peak heights were 0.4%~2.2% and 0.1%~1.5%(n=5),respectively.The method has been applied to the determination of inorganic anions in mineralized water and groundwater with satisfactory results.Recoveries of inorganic anions after spiking were 97.9%~100.3%.