抗坏血酸还原法测定工作场所空气中的磷酸含量

Determination of Phosphoric Acid Content in the Air of Workplace using Ascorbic Acid Reduction Method

为了建立工作场所空气中磷酸含量的测定方法,利用磷酸与钼酸铵生成磷钼酸铵,抗坏血酸再将磷钼酸铵还原生成蓝色络合物的性质,对抗坏血酸还原法进行了优化。结果表明:空气样品中加入4.5 mol/L硫酸溶液4.0 mL、40 g/L钼酸铵溶液1.0 mL、17 g/L抗坏血酸溶液1.5 mL,沸水浴显色反应25 min,最后在815 nm波长处进行检测,磷酸检出限为0.016μg/mL,最低检出浓度为0.011μg/mL(以采集75 L空气样品计),测定范围2~200μg,回收率98.0%~101.7%。该方法简单快捷、灵敏度高、试剂用量少,适合工作场所空气中的磷酸含量测定。

To establish a method for the determination of phosphoric acid in the air of workplace, the ascorbic acid reduction method was optimized, under the acidic conditions, phosphoric acid reacts with ammonium molybdate to generate the ammonium phosphomolybdate. Ammonium phosphomolybdate then reacted with ascorbic acid to generate the blue complex. The results showed that the air samples with 4.0 mL of 4.5 mol/L sulphuric acid, 1.0 mL 40 g/L ammonium molybdate solution, 1.5 mL 17 g/L ascorbic acid-solution, chromogenic reaction of 25 min in a boiling water bath, finally are tested under a wavelength of 815 rim, phosphoric acid detection limit is 0.016 μg/mL, and the minimum detectable concentration is 0.011 μg/mL （Collect 75 L air samples） This method is simple, fast, high sensitive, and less reagents consumption. The determination range of 2-200 μg, the recovery rate is 98%-101.7%. This method will provide a better choice for the phosphorylation determination in the workplace air.