硝酸对ICP-OES测定水中铜铅锌镉的影响

Effects of Nitric Acid on Determination of Copper,Lead,Zinc and Cadmium in Surface Water by ICP-OES

在使用ICP-OES测定水中铜、铅、锌、镉元素时,为防止重金属元素水解沉淀,在样品采集时,通常会在待测样品中加入浓硝酸并使得水样中硝酸含量达到1%的浓度。由于浓硝酸具有强腐蚀性及强挥发性,1%的浓度是否为精确配制直接影响着操作速度及接触硝酸的时间,对实验中长期接触硝酸的操作者来说有着很重要的意义。因此,为了研究硝酸对ICP-OES测定水中铜、铅、锌、镉元素的影响,用混合标准使用液配制了浓度为0.1 mg/L、0.4 mg/L的标准溶液,比较两个浓度点的标准溶液在不同硝酸浓度溶液中铜、铅、锌、镉的测定结果,得出较低浓度硝酸,对测定结果无显著性影响。

When the concentrations of copper, lead, zinc and cadmium in water are measured by ICP - OES, nitric acid is usually added to the sample to increase the concentration of nitric acid by 1% in order to prevent hydrolysis precipitation of heavy metal elements. However, the nitric acid has strong corrosion and volatility, the precision of nitric acid concentration will directly affect the operation speed and contact time with nitric acid and is also very important for operators under long -term exposure. To study the nitric acid effects on determi- nation of copper, lead, zinc, and cadmium in surface water by ICP- OES, standard solutions of 0. 1 mg/L and 0.4 mg/L were prepared with a mixture of standard solutions, the determination results of copper, lead, zinc and cadmium in the two standard solutions with different concentration of nitric acid were compared. The results show that no obvious effect on the determination results when the nitrate concentration is low.