溶液阴极辉光放电光谱信号的内标法定量分析研究

溶液阴极辉光放电-原子发射光谱是一种新颖的快速、高效、实时在线的元素分析方法,它可用于水体金属元素的检测。为提高其测量精确度和稳定性,将内标法应用于溶液阴极辉光放电-原子发射光谱技术。对K元素建立了标准定标曲线和以H_β为内标元素的定标曲线,内标法测得样品的相对误差和相对标准偏差分别为1.11%,2.14%,精确度和稳定性较之标准曲线法有一定的提高。实验考察了元素谱线强度在同一时段的波动情况,发现元素K和H_β的谱线强度变化趋势稍有不同,而同主族元素K和Rb,Ca和Mg的谱线强度有相同的变化趋势,提出选择与待测元素同主族且谱线强度变化趋势较为一致的元素作为内标元素能更大化校正实验波动的观点。同时探讨了K以Rb为内标元素、Ca以Mg为内标元素以及Mg以Ca为内标元素时的内标法测量的精确度和稳定性,得其相对误差分别为0.49%,0.02%和0.30%,相对标准偏差分别为1.11%,1.13%和0.87%,与标准曲线法和以H_β为内标元素的内标法相比效果更佳。测得自来水样品中Ca元素以Mg为内标的相对误差和相对标准偏差为0.58%,1.03%,Mg元素以Ca为内标的相对误差和相对标准偏差为1.57%和1.10%。研究结果表明,将溶液阴极辉光放电-原子发射光谱技术应用于水体金属元素检测时,内标法可以有效校正实验波动的影响,提高测量的精确度和稳定性。

Quantitative Analysis of Solution Cathode Glow Discharge-Atomic Emission Spectroscopy Coupled with Internal Standard Method

Solution Cathode Glow Discharge-Atomic Emission Spectrometry is a novel,rapid,high efficient and real-time online element analysis method,which can be applied for metal elements detection in water.In this paper,the internal standard method was employed to improve its accuracy and stability.The standard calibration curve of potassium and the internal standard calibra-tion curve of potassium were established using Hβas internal standard elements,and the relative error and relative standard devi-ation of the sample measured by internal standard method were 1.11% and 2.14%,respectively.Compared with the standard curve method,the accuracy and stability were improved by internal standard method.Variations of spectral line intensity at the same periods were investigated,showing the spectral line intensity variations of potassium and Hβwere not quite the same,but the spectral line intensity variations of potassium and rubidium,calcium and magnesium in the same main group had the same variable trends,thus,we proposed that the elements which had the same variable trends of spectral line intensity and main group with the determined metal elements could be selected as the internal standard element to have a greater correction for metal ele-ments detection in water using solution cathode glow discharge-atomic emission spectrometry.The accuracies and stabilities of internal standard method when rubidium,magnesium and calcium were used as internal standard elements for potassium,calcium and magnesium were discussed and the relative errors were 0.49%,0.02% and 0.30% respectively,and the relative standard deviations were 1.11%,1.13% and 0.87%,respectively,which is better than the standard curve method and the internal standard method using Hβas the internal standard element.The relative error and relative standard deviation of the calcium and magnesium in tap water were also measured,which showed that the relative error and relative standard deviation were 0.58%, 1.03% and 1.57%,1.10%,respectively,when magnesium and calcium were used as the internal standard spectral elements re-spectively.The results show that the internal standard method is a useful method to eliminate the influence of experimental fluc-tuations,which improves the accuracy and stability when solution cathode glow discharge-atomic emission spectrometry is ap-plied for metal elements detection in water.