矿泉水中偏硅酸测定有关探讨

A discussion about determination of metasilicic acid (H_2SiO_3) in mineral water

目的：通过实验找出在波长350nm处测定矿泉水中偏硅酸，建立消除亚铁离子干扰矿泉水中偏硅酸测定的分析方法。方法：矿泉水加盐酸酸化后，加钼酸铵显色30min，在波长350nm处比色测定消除了亚铁离子干扰。结果：偏硅酸显色后在350nm波长处比色测定，溶液显色后颜色稳定，含量在50．0～500．0μg之间线性良好，相关系数（r）=0．9985；最低检测质量浓度为1．0μg／ml；50μg标准和样品的相对标准偏差（RSD）为2．8％和3、6％；回收率：97．3％．103．0％。结论：该方法简单、快速、灵敏，测定结果准确可靠，适合有或无亚铁离子存在的矿泉水中偏硅酸的测定；实用性强，无特殊条件的要求，基层和各级实验室都可参照测定。

Objective：To develop a method for determination of metasilicic acid（H2SiO3 ） in mineral water at the wavelength of 350 nm and study on the ferrous ion＇s interference elimination. Methods： Mineral water was acidated by adding HCl, adding ammonium molybdate, then the reacting results were coloured. After 30 minutes, it was determined at the wavelength of 350 nm by colorimetric analysis, and the ferrous ion＇s interference was eliminatd. Results： Metasilicic acid（ H2SiO3 ） was determined at the wavelength of 350 nm, the colour was stable. The linearity was favourable in the range of 50. 0 - 500. 0 μg, the correlation coefficients was 0. 9985, and the detection limit was 1.0 μg/ml. RSD of the standard with the certified value 50 μg and the sample was 2. 8% and 3.6%, the recoveries were between 97.3% and 103%. Conclusion：The method is sensitive, selective and rapid with simple instrument, satisfactory result is obtained for the determination of metasilicic acid（ H2SiO3 ） in mineral water.