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土壤中硫酸根离子的测定一般采用比浊法,重量法和EDTA容量法等。交流示波极谱滴定法是在含S0_4~(2-)试液中加入定量过量的P_a(2+)标准溶液之生成BaSO_4沉淀(不必过滤),过量的Ba_(2+)直接用K_2r_20_7标准溶液滴定,以CrO_4~(2-)在示波图上出现切口指示终点,然后根据所消耗的Cr_2O_7~(2-)来计算SO_4~(2-)的含量。此方法终点直观,不受沉淀和颜色的限制,操作简便,仪器简单,方法快速,准确可靠,可与经典的重量法媲美。此法用于测定土壤中可溶性SO_4~(2-)的含量,回收率可达98％—101％,结果满意。
Determination of sulfate ions in soil generally turbidimetry, gravimetric method and EDTA volumetric method. The exchange oscillopolarographic titration method is to generate the BaSO_4 precipitate (without filtering) by adding a quantitative excess of P_a (2+) standard solution to the S0_4 ~ (2-) test solution. The excess Ba_ (2+) is directly measured by the K_2r_20_7 standard Solution titration, with CrO_4 ~ (2-) in the oscillogram appears incision endpoint, and then calculated by consumption of Cr_2O_7 ~ (2-) to calculate the content of SO_4 ~ (2-). The end of this method is intuitive, without precipitation and color restrictions, easy to operate, the instrument is simple, fast, accurate and reliable, comparable with the classic gravimetric method. The method was applied to determine the content of soluble SO_4 ~ (2-) in soil, the recovery rate was 98% -101%, with satisfactory results.