摘要
我国的环境标准分析方法中,水的硬度系采用EDTA滴定法。标准方法提及:“有些金属离子使铬黑T退色,或使终点不明显”;“水样中的悬浮物或胶状物也影响终点”;“滴定时最好在常温下进行,因为温度太低时颜色变化较缓慢。
Calcium and magnesium in water samples were determined by using an apparatus with a dual-wavelength fiber-optic probe for semi-automatic photometric titration. The subtraction of the signals of two light beams of different wavelength which pass the same titration solution eliminated the turbidity and dilution effects and increased titration sensitivity. No interference was found as the amounts of suspension was less than 20 mg in 50 ml sample solution. It took 1 -2 min. for single titration. The limits of detection and measurement range of calcium and magnesium are 0.14μg, 0.09μg (3.6× 10-9mol) and 4μg-40mg 2.4 μg-24mg respectively. R. S. D. and recovery of this method are 0.12% and 101.2% respectively. Analytical results of this method for six kinds of water samples are in agreement with that of A. A. S. method
出处
《环境科学》
EI
CAS
CSSCI
CSCD
北大核心
1989年第2期50-53,共4页
Environmental Science
