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采用差分脉冲伏安法测定了饮用水中的Mn~(2+)。探讨了仪器自身条件和不同的底液条件对Mn~(2+)的峰高和峰型的影响。通过比较不同条件下Mn~(2+)的峰高和峰型,确定测量Mn~(2+)的最佳条件如下:Hg面积为0.52 mm2、搅拌速率为3000 min~(-1)、富集时间为320 s、平衡时间为20 s、起始扫描电压为-1.65~-1.60 V、终止扫描电压为-1.25 V、富集电压为-1.70 V、扫描速率为0.01V/s、振幅为25 m V,底液为0.5 m L的0.2 mol/L的Na_2HPO_4和5.0 m L的0.5 mo L/L的H_3BO_3溶液。在0~21.75μg/L范围内,峰电流与质量浓度呈线性关系,R=0.998。在最佳条件下测定饮用水中的Mn~(2+),质量浓度为0.718~2.033μg/L,RSD为2.1%~9.7%,检出限为0.015μg/L。样品加标回收率为97.8%~107.9%,RSD%为1.7%~10%。
The differential pulse voltammetry was used to determine the Mn ~ (2+) in drinking water. The effects of the instrument conditions and different conditions of the bottom solution on the peak height and peak shape of Mn 2+ were discussed. The optimum conditions for the determination of Mn ~ (2+) were as follows: the area of Hg was 0.52 mm2, the stirring rate was 3000 min ~ (-1), the enrichment time For 320 s, the equilibration time is 20 s, the initial scan voltage is -1.65 ~ -1.60 V, the final scan voltage is -1.25 V, the concentration voltage is -1.70 V, the scan rate is 0.01 V / s and the amplitude is 25 m V, 0.2 mol / L Na_2HPO_4 with 0.5 mL and 0.5 mL L_ (0.5 mL) H_3BO_3 solution. In the range of 0 ~ 21.75μg / L, the peak current was linear with mass concentration, R = 0.998. The optimal conditions for determination of Mn ~ (2+) in drinking water were 0.718 ~ 2.033μg / L, RSD 2.1% ~ 9.7% and detection limit 0.015μg / L. The recoveries of spiked samples ranged from 97.8% to 107.9% with RSD% of 1.7% -10%.