基于紫外热消解的小型自动化总磷检测系统

Small automatic total phosphorus testing system based on ultraviolet digestion

该文面向水环境污染及检测重要指标总磷检测系统的开发,优化小型水样消解预处理系统,研究磷酸盐电化学检测方法,实现一种小型自动化总磷检测系统。该检测系统由消解单元和检测单元组成。经优化该系统在254 nm波长紫外光、相对低的消解温度(80℃)、无需添加强氧化剂的情况下,对总磷系列标准溶液的平均消解效率为82%。总磷检测单元采用金工作电极,基于磷钼酸还原反应原理的电化学检测方法,采用线性扫描伏安法对总磷的浓度响应特性进行检测。结果显示该电极对磷酸根溶液在0.1 mg/L^1.0 mg/L浓度范围内有线性电流响应,灵敏度达到1.477 0μA/(mg·L-1),线性相关系数为0.993 3。该检测系统具有较高的准确性,检测偏差控制在20%以内。研究结果表明,研制的自动化总磷检测系统具有小型化、功耗低、消解效率高、无需强氧化剂的特点,将有望用于总磷的在线监测。

The development of small total phosphate testing system and the study of phosphate electrode are proposed in order to optimize the pretreatment system of small water sample digestion. Digestion is performed for each electrode before testing. A digestion pretreatment system for water treatment based on ultraviolet photo-catalytic method is optimized. A 254 nm wavelength UV light is used in this system, and gold is selected as sensing material. The volume of digested water sample or actual sample is measured. These electrodes are applied to detect total phosphorus concentration in water samples from lake. The experiment results demonstrate that the system shows high sensitivity in the concentration range of 0.1 mg/L–1.0 mg/L(R2=0.993 3) and a low detection limit(0.1 mg/L) in the slope around 1.477 0 μA/(mg·L-1). The proposed total phosphate testing system bears the characteristics of small size, low power consumption, high digestion efficiency and has no need of strong oxidizing agent, which is expected to be used for online-monitoring of total phosphorus.