激光诱导击穿光谱与火焰光度法定量分析土壤钾元素含量

Quantitative analysis of potassium in soil using laser induced breakdown spectroscopy and flame photometry

利用激光诱导击穿光谱技术(Laser Induced Breakdown Spectroscopy,LIBS)对漯河市周边5个不同地点收集的土壤样品进行K元素含量测定,评估LIBS技术对土壤K元素含量的分析能力。采用火焰光度法获得K元素含量参考值,火焰光度法平行测量误差为±5%。在K元素含量9～35μg·g-1范围内,5个点的土壤样品测量相对标准偏差分别为0.075%、0.081%、0.096%、0.134%和0.47%。采用洛仑兹拟合算法,计算K元素在766.49 nm和769.90 nm谱线上的信噪比,通过对比选取766.49 nm为土壤K元素LIBS特征光谱线。用离差标准化(Min-Max Normalization)和统计权重矩阵对LIBS试验数据进行分析,建立K元素含量定标曲线,5种样品相关系数分别为0.913、0.917、0.88、0.914和0.866。

This study evaluates the analyzing capability of Laser Induced Breakdown Spectroscopy(LIBS)method for quantification of the element K contents in soil by measuring the soil samples collected from5different locations in Luohe city.Flame photometer was used to obtain reference concentrations of K element,and an error of±5%was obtained from these parallel experiments.Relative standard deviations(RSD)of0.075%,0.081%,0.096%,0.134%,and0.47%were obtained in the K concentrations ranging from9to35μg·g^-1of soil samples from5locations.After calculating the signal-to-noise ratios at the spectral lines of766.49nm and769.90nm with Lorentz fitting method,766.49nm was selected as the optimal wavelength for the determination of concentrations of K element.The LIBS experimental data were processed by Min-Max Normalization and the statistical weight matrices.Correspondingly,the calibration curve for the determination of K concentrations in5different samples was established with the correlation coefficients of0.913,0.917,0.88,0.914,and0.866,respectively.