微波消解-磷钒钼黄光度法测定海洋沉积物中总磷

采用微波消解样品,磷钒钼黄光度法测定海洋沉积物中总磷。优化了消解用酸的种类和用量、消解时间、消解温度等微波消解条件。选择HNO3作为消解剂,消解最终温度190℃,保持时间15 min,总磷的测定快速和准确。探讨了显色酸度(微波消解液是否需要赶酸)和稀释倍数等测定条件。对两种国家一级沉积物标准物质GBW07314和GBW07311进行分析验证,测定值与标准值相符,相对标准偏差(RSD,n=6)分别为0.74%和1.66%。与常规消解方法进行比对实验,测定结果无显著性差异。与国标GB 17378.5方法相比,该法具有简单、快速、准确、空白值低、环境污染少等优点。在实际样品测定中,取得了满意的结果,适用于海洋沉积物中总磷的测定。

Determination of Total Phosphorus in Marine Sediments by Microwave Digestion-Phosphorus Vanadium Molybdenum Yellow Spectrophotometry

A new method to determine total phosphorus in marine sediments by phosphorus vanadium molybdenum yellow spectrophotometry with microwave digestion is presented in this paper.The working parameters of the microwave digestion instrument,including digestion reagent species and dosage,digestion time and temperature were optimized.The samples were dissolved by HNO3 at the temperature of 190℃ for 15 min.The determination conditions including acidity for color-display and dilution factor were discussed to achieve a fast and accurate measurement for total phosphorus.The method has been validated by determination of total phosphorus in National Standard Reference materials GBW0731 and GBW07311.The results are in agreement with certified values and have a precision of 0.74% and the relative standard deviation(RSD,n=6) of 1.66%.Compared with the traditional digestion method,there is no significant difference between the two methods.However,the microwave digestion method is simple,rapid,accurate,low blank and contributes less pollution,compared to the National Standard method of GB 17378.5.Results of actual samples indicate that the method is suitable for the determination of total phosphorus in marine sediments.