显色酸度对钼锑抗分光光度法测定土壤中总磷的影响

Exploration on the Effect of the Colorred-Solution Acidity in Determining Total Phosphorus in Soil by Molybdenum Antimony Anti-Spectrophotometry

采用碱熔-钼锑抗分光光度法测定土壤中总磷时,显色溶液的酸度影响磷钼络合物的形成和稳定,p H指示剂2,4-二硝基苯酚在环境温度低时配制困难、辨色不明显。分析了显色酸度对吸光值的影响,并对2,4-二硝基苯酚的配制方法进行了改进,方法操作简单,提高了分析结果的准确性。

When using the alkali fusion-molybdenum antimony anti-spectrophotometric method for the determination of total phosphorus in soil, several problems were present including the influence of solution acidity on the formation and stability of the phosphorus molybdenum complex, difficulty in making the pH indicator 2,4-dinitrophenol at low ambient temperature and the coloration was not obvious for identification. This paper studied the effect of the acidity of the colorred solution on the absorbance value and improved preparation method for the 2, 4-dinitrophenol indicator. The modified method is simpler in operation and more accurate in analysis.