基于ICP-AES法测定太湖溶解态有机磷的初步研究

Preliminary Study on Dissolved Organic Phosphorus Determination by ICP-AES Method in Lake Taihu

以2010年5月27日太湖水样为测试对象,进行典型溶解性有机磷（草甘膦和植酸）的ICP-AES加标回收试验验证C18柱去除有机磷的能力,探讨了样品消解在ICP-AES法测定TSP过程的作用,使用ICP-AES法测定水样中不同形态磷含量间接定量太湖DOP水平,并与传统方法测得的DOP含量作对比。结果表明,过C18柱可去除水样中96%以上的有机磷,能实现过滤前后水样有机物差异的效果;水样经过消解后测定值（TSP）为0.025~0.095 mg/L,大大高于未消解系列测得值（0.009~0.030 mg/L）,ICP-AES法测定有机磷含量较高的水样时需要经过消解的预处理步骤;使用ICP-AES与C18柱相结合的方法测得太湖DOP含量为0.014~0.069 mg/L之间,大大高于传统比色法DOP测得值0.026~0.083 mg/L,前法能更准确的间接定量水体中DOP水平,而后法可能会大大高估DOP在水环境中的实际含量。

Samples collected from Lake Taihu on May 27, 2010 were used in removal experiment to validate the removal rates of representative dissolved organic phosphorus （DOP） such as glyphosate and phytic acid with C18 column, and role of digestion in measurement of total soluble phosphorus （TSP） by ICP-AES was also discussed. Different phosphorus fractions in samples were indirectly measured based on ICP-AES coupled with preliminary treatment with C18 column. Compared with traditional molybdenum-antimony anti-spectrophotometric methods on DOP determination, results showed that more than 96% of DOP can be successfully removed with C18 column. TSP concentrations determined by ICP-AES after digestion ranged from 0.025 mg/L to 0.095 mg/L, while samples without digestion were determined in the range of 0.009-0.03 mg/L, suggesting that digestion was necessary for DOP determination of water samples containing high levels of organophosphorus by ICP-AES method. Concentrations of DOP ranging from 0.014 mg/L to 0.069 mg/L were observed in samples by ICP-AES pretreated with C18 column, which were obviously higher than those determined by traditional methods as DOP ranging from 0.026 mg/L to 0.083 mg/L. It was evident that DOP levels determined by traditional method were overvalued; on the contrary, a much more accurate measurement on DOP could be obtained by ICP-AES coupled with C18 column pretreatment.