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本文提出了应用氯冉酸钡测定盐碱土中水溶性硫酸盐的分光光度分析方法。土壤浸提液中的干扰阳离子用钠型阳离子交换树脂振荡处理,可以避免使用氢型树脂引起 pH改变缺点。树脂的分离以及含硫酸钡、过量的氯冉酸钡沉淀与溶液的分离均采用离心的方法。所用的土壤浸提液较使用离子交换柱者为少。取交换后的溶液1-4毫升可供分析含硫酸根0.05-1.5%的土壤。缓冲溶液选用醋酸与醋酸钠,因为它易于得到,且有较大的缓冲容量。向土壤浸提液中加入硫酸根的回收率为99.8±0.1%。对八种土壤样品的分析结果与重量分析法相比其绝对相差小于0.01%。一个浸提液的分析约需半小时左右,每人每天用此法可以分析30个土壤浸提液样品的重复测定。本文还提出了回收氯冉酸钡和再生树脂的手续。本法是盐碱土中硫酸盐分析的一个比较快速、简单和准确的方法。
This paper presents a spectrophotometric method for the determination of water-soluble sulphate in saline-alkali soil using barium tranexamate. The disturbing cations in the leaching solution of the soil are treated with a sodium cation exchange resin to avoid the disadvantage of using a hydrogen type resin to change the pH. Resin separation and containing barium sulfate, excessive precipitation of barium tranexamic acid and the solution are separated by centrifugation. Soil extracts used were less soluble than ion exchange columns. Take 1-4 ml of exchanged solution for analysis of soil with 0.05-1.5% sulfate. Acetic acid and sodium acetate are used as the buffer solution because it is easy to get and has a large buffer capacity. The recovery of sulfate added to the soil extract was 99.8 ± 0.1%. The absolute difference between the analytical results of the eight soil samples and gravimetric analysis is less than 0.01%. Analysis of a leachate takes about half an hour or so per person per day using this method to analyze repeated determinations of 30 soil extracts. This paper also proposed the procedure of recovering barium tranexamate and regenerating resin. This method is a quick, simple and accurate method for sulphate analysis in saline-alkali soil.