Abstract: A comprehensive analytical method based on solid phase extraction-ion chromatography (SPE-IC) has been developed for the determination of trace perchlorate in groundwater. An amount of 0.7 liter of groundwater was enriched by a solid phase extraction column after pretreatment to remove the interference ions and then the column was eluted by 6 mL 1% NaOH solution. After filtration of the concentrated liquor with a filter membrane (0.45 μm), the liquor was analyzed on an ion chromatograph (IC) equipped with an Ion Pac AS20 separation column and a 50 μL injection loop, eluted with 40 mmol/L KOH solution. The method detection limit (MDL) and limit of determination (LOD) of perchlorate were 0.15 μg/L and 0.60 μg/L, respectively. The recovery was in the range of 99.7%~100.5% when the sampling concentrations were in the range of 1~15 μg/L. The method is economical and effective. It can be applied to determine trace perchlorate in groundwater. The perchlorate in groundwater samples got from the areas surrounding Harbin was determined by this method. The relative errors were in the range of 1.85%~9.24% between the results got by the SPE-IC and ion chromatography-tandem single quadrupole mass spectrometry.

Key words: groundwater, interference ions, ion chromatography (IC), perchlorate, solid phase extraction (SPE)