建立了离子色谱直接进样测定车用尿素溶液中Ca2+的方法。选择Metro sep C3–250型色谱柱，以5 mmol／L硝酸为淋洗液，非抑制电导检测模式。Ca2+质量浓度在0.05~1.0µg／mL范围内与色谱峰面积呈良好线性，相关系数r=0.9998，实际样品的定量限为0.025µg／mL，0.10µg／mL水平Ca2+加标回收率为97.44%，相对标准偏差为4.68%(n=6)，可满足ISO 22241标准中Ca2+的分析要求。该法具有无试剂干扰、操作简便、分析速度较快的特点，检测结果与ISO 22241标准中ICP–OES方法无显著性差异。%Calcium ion in automobile urea solution was determined by ion chromatography with non-suppressed con-ductance, Metro sep C 3–250 as separation column and 5 mmol/L nitric acid as the eluent. The concentration of Ca2+was linear with chromatographic peak area in the range of 0.05–1.0 µg/mL with the correlation coefficent of 0.999 8. The re-covery rate of 97.44%was reached with 0.10 µg/mL calcium ion, and the relative standard deviation was 4.68%(n=6). The detection limit of actual samples was 0.025 µg/mL. Both the accuracy and precision of the method could meet the require-ment of ISO 22241. The method provided with no reagent interference as well as complex operations. The results detected by IC and ICP–OES were no significant difference.
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