ICP-AES、石墨炉原子吸收光谱法及X射线荧光光谱法测定土壤中钒的比较

研究了土壤中钒的3种测定方法,ICP-AES、石墨炉原子吸收光谱法和X射线荧光光谱法.其中ICP-AES选用谱线V 311.1nm,用干扰系数法,干扰系数用多个土壤标样的标准值和测定值的最小二乘法来确定;石墨炉原子吸收光谱法用新、旧石墨管(热解涂层),加与不加基体改进剂(硝酸镁)分别进行测试;X射线荧光光谱法样品无需前处理、无需做校准曲线,测定前仪器用自带校正钢片单点法进行校正.通过测试结果的比较得出:ICP-AES测定土壤标样中的钒,精密度高,准确度好,适合土壤中钒的实验室分析;石墨炉原子吸收光谱法灵敏度过高(高一个数量级),信号稳定性较差,对高温元素钒的测定最好加硝酸镁机体改进剂消除基体干扰且每只石墨管分析次数不超过100次；X荧光光谱法较适合于野外监测或土壤样品无损检测,操作方便快速.

Comparison of Determination of Vanadium in Soil by ICP-AES,GFAAS and X-Ray Fluorescence Spectrometry

Three methods for the determination of vanadium in soil such as ICP-AES,graphite furnace atomic absorption(GFAAS) and X-ray fluorescence spectrometry were researched.In ICP- AES,spectral line V 311.lnm was chosen,and interference factor method was used.The interference factor was determined by the least square method with the standard values and measured values of many standard soil samples.In GFAAS is determined by new and old graphite pipes(pyrolytic coating) through adding or without adding matrix modifier(magnesium nitrate).In X-ray fluorescence spetrometry,the samples don’t need pretreatment or standard curve,and the equipment should be calibrated with the attached calibrating steel discs by single point method before testing. Through comparison of the testing methods,ICP-AES can make out highly accurate and precision results in testing of vanadium in standard soil samples,and is suitable for lab analysis of vanadium in soil.The GFAAS has too high sensitivity(over a quantity level),and has poor signal stability,when high temperature element vanadium is determined,matrix modifier magnesium nitrate should better be added in order to eliminate interference,but analysis times of each,graphhite are no more than 100. The X-ray fluorescence spetrometry is very suitable for open-air monitoring or non-damage soil sample testing,with convenient and quick operation.