顺序注射光度法测定水体中正磷酸盐

Determination of orthophosphate in water by sequential injection analysis and spectrophotometry

应用FIAlab-3500顺序注射分析仪,采用钼锑抗分光光度法测定水中的正磷酸盐,对实验参数进行了优化.实验结果表明,正磷酸盐质量浓度在0～5 mg/L范围内与吸光度呈良好线性关系,方程为y=0.112 8x-0.005 1（R2=0.999 2）,空白相对标准偏差（RSD）为1.2％,方法的检出限为0.009 3 mg/L.利用该法测定某管网水中正磷酸盐,测得其加标回收率为96％～105％.

By using ammonium molybdate spectrophotometric method, orthophosphate in water was determinated by FIAlab- 3500 sequential injection analysis system, and the experimental parameters were optimized. The results show that orthophos- phate concentration is in the range of 0-5 mg/L and the absorbance is linear. The linear equation is y=0. 112 8x-0. 005 1 （R2 =0. 999 2）, and blank relative standard deviation （RSD） is 1.2%. The limit of detection is 0. 009 3 mg/L. The ortho- phosphate in pipe network water is analyzed and the recovery of standard addition is 96%-105%.