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水中微量硫酸根离子,通常用比浊法进行测定,由于形成硫酸钡颗粒的反应条件要求严格,以及共存离子共沉淀的影响,致使测定结果再现性差,本文介绍的是以二甲基偶氮磺Ⅰ为指示剂,用高氯酸钡滴定硫酸根的微量滴定法,终点自紫红变为蓝绿,色差十分明显,再现性好,可测低限为5PPm,误差小于5％。本文对滴定条件的选择和控制;阳离子的干扰影响及排除,作了探讨。 (一)滴定条件的选择在不同浓度的丙酮介质中;不同的pH值下,指示剂和钡配合物各自显示不同的颜色。试验证明,在
Trace sulfate ions in water are usually measured by nephelometry. Due to the strict reaction conditions for the formation of barium sulfate particles and the coexistence of ion coprecipitates, the reproducibility of the determination results is poor. In this paper, Ⅰ as indicator, titration with barium perchlorate sulfate microtiter method, the end point from purple to blue-green, the color difference is very obvious, reproducible, the lower limit of 5PPm, the error is less than 5%. In this paper, the selection and control of titration conditions; the influence and elimination of cation interference are discussed. (A) Titration conditions are selected in different concentrations of acetone media; indicator and barium complexes each show a different color at different pH values. Test proved that