面向水中磷酸盐的现场、自动检测, 研制水中磷酸盐小型自动化光学检测系统, 基于钼酸铵分光光度法, 搭建磷酸盐光学检测平台。系统在 660 nm波长的光源照射下, 测试不同浓度磷酸盐溶液的光电流, 采用最小二乘法进行磷酸盐溶液的曲线标定, 并对检测系统的检测范围、重复性以及检测准确性等性能进行测试。实验结果表明, 在磷酸盐浓度为 0.01~0.7 mg/L范围内, 光学检测平台输出的光电流信号经自动检测系统处理后得到的吸光度值与磷酸盐的浓度呈线性关系, 线性相关系数为99.93%, 重复测试相对标准偏差优于 2%; 与商用磷酸盐手动检测系统进行比对测试, 测试相对偏差在 10%以内。研制的磷酸盐小型自动化检测系统日后可用于检测国家地表水质量标准中规定的 I~Ⅴ类水中的总磷含量 (0.02~0.4 mg/L)。

Aiming at field automatic detection of phosphate in water, a small-sized automatic optical system for detection of phosphate in water is developed, based on ammonium molybdate spectrophotometric method. The photocurrents of phosphate samples with different concentrations are detected by the developed system with the light source wavelength of 660 nm. The standard curve is fitted with the least square method. The detection range, repeatability and accuracy of the system are measured. The experimental results indicate that there exists a linear relationship between the absorbance value processed by the automatic system and the concentration of phosphate in the concentration range of 0.1–0.7 mg/L(R2=99.93%), and with a Relative Standard Deviation(RSD) superior to 2 %. Compared with thecommercial manual system for phosphate detection, the relative deviation of the developed system is within 10%.The system can be further applied to detect the amount of total phosphate in the water of class I–V(0.02–0.4 mg/L) prescribed in the national surface water environmental quality standards.ucas.ac.cn