固相萃取-离子色谱法测定地下水中痕量的高氯酸根离子

Determination of trace perchlorate in groundwater by solid phase extraction-ion chromatography

建立了测定地下水中痕量高氯酸根(ClO 4-)的固相萃取-离子色谱(SPE-IC)分析方法。0.7 L水样经预处理降低主要干扰离子Cl-、CO23-和SO24-的干扰后,使用Cleanert PWAX弱阴离子交换固相萃取小柱对地下水中痕量(μg/L级)的ClO 4-进行富集,用6 mL 1%NaOH溶液洗脱,富集液经0.45μm水膜过滤后,用IonPac AS20阴离子分离柱、50μL进样环、40 mmol/L KOH溶液淋洗、抑制电导检测分离分析。结果表明,地下水样品中ClO 4-的方法检出限和测定下限分别为0.15μg/L和0.60μg/L,进样质量浓度在1～15μg/L范围内有很好的线性关系,线性相关系数为0.999 2,回收率为99.7%～100.5%;该方法经济有效,可用于地下水中痕量ClO 4-的检测。利用该方法测定了哈尔滨周边部分地区地下水中ClO 4-浓度,检测结果与离子色谱-质谱联用法的检测结果的相对误差为1.85%～9.24%。

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.