汞监测中水样保存条件的研究

Study on preservation conditions of water sample for mercury measurement

目的:研究汞监测中水样的保存最佳条件。方法:采用H2SO4-KMnO4消解体系、冷原子荧光光谱法,分析水样在不同保存条件下,水中汞的稳定性的变化规律。结果:水中汞的稳定性随酸度增加而增加,酸类保存剂的保存效果为HNO3>HC l>H2SO4;氧化剂K2Cr2O7对水中汞的稳定效果优于KMnO4,氧化剂的用量应根据水中还原物质的含量确定;玻璃瓶保存水样中汞的效果优于塑料瓶。结论:汞监测中选用硝酸和盐酸,添加量为取样量的1%左右;氧化剂选用重铬酸钾,添加量可根据被测水质的CODC r值确定;贮存器选用玻璃瓶优于塑料瓶。水样保存时应根据水质特征添加保存剂。

Objective：To investigate the preservation condition of mercury in water sample. Methods：With the digestion system of H2SO4 - KMnO4 and the method of cold atomic fluorescence spectrum, the effect of mercury density in water sample with different protective agent and time was studied. Results：The stability of mercury in water sample was increased when the acidity increased, preservation effect of acids protecting agent was HNO3 〉 HCL 〉 H2SO4. The stability of mercury in water was stored with K2 Cr2 O7 is better than with KMnO4. The consumption of oxidant should follow the value of disoxidation in water sample. The stability of mercury in water stored with glass bottle was better than that with plastic bottle. Conclusion：In mercury measurement, HNO3 or HC1 is used for acidifier and adding amount is 1% of water sample. K2Cr2O7 is used for oxidant and the dose of oxidant should be followed the value of CODCr in water sample. The preservation of water sample should follow the water quality characteristic and take a suitable method. The waste water sample measurement should be done within 24 hours.