石墨炉原子吸收法测定水中微量元素钡的方法探讨

Determination of Trace Element Barium in Water by Graphite Furnace Atomic Absorption Spectrometry

采用石墨炉法测定水中微量元素钡,首先采用浸渍法对石墨管进行涂层实验,选用了三种物质,分别是硝酸镧、八水合氧氯化锆、钨酸钾,结果显示涂镧石管的效果最好。采用单因素实验法,确定了灰化温度、原子化温度分别为1 000℃、2 500℃为最佳测量参数。配置了0μg/L~80μg/L的钡标准系列,曲线相关系数为0.999 6,线性良好,样品加标回收率为97%~104%,相对标准偏差为2.8%,准确性与精密度良好。总之采用涂镧石管和加入基体改进剂两种改进方法,既减少了前期对石墨管的投入,又达到了很好的灵敏度、线性、准确度和精密度。

In this article, the trace element barium in water is determined by graphite furnace method. Firstly, the coating experiment of graphite tube is carried out by impregnation method. Three substances are selected: lanthanum nitrate, zirconium oxychloride octahydrate and potassium tungstate. The results showed that the effect of lanthanum coated stone tube is the best. The ashing temperature and atomization temperature of 1 000 ℃ and 2 500 ℃ are determined as the best measurement parameters by single factor experiment. Configured 0 μg/L~80 μg/L barium standard series, the curve correlation coefficient is 0.999 6, the linearity is good, the sample spiked recovery rate is 97%~104%, the relative standard deviation is 2.8%, and the accuracy and precision are good. In short, the use of lanthanum coated graphite tube and the addition of matrix modifier can not only reduce the investment in graphite tube in the early stage, but also achieve good sensitivity, linearity, accuracy and precision.