将激光诱导击穿光谱技术与双谱线定量分析方法结合对土壤中镁元素进行分析,选取镁(Mg)元素的383.8 nm原子谱线和823.5 nm离子谱线作为分析线。对21个不同浓度的土壤样品,根据原子、离子谱线强度与镁(Mg)元素浓度值分别建立定标曲线,相关系数分别为0.911和0.888。针对分析结果采用双谱线定量分析方法对21个土壤样品建立定标曲线,相关系数提高到0.950,检测限为0.008%。根据定量模型对9个验证样品的浓度进行预测,相对误差为0.41%～5.32%,平均误差为1.84%。

The quantitative analysis of Mg in soil was determined by laser-induced breakdown spectroscopy (LIBS) combined with double-spectrum analysis in this paper. The characteristic spectral line of 383.8 nm (atomic line) and 823.5 nm (ion line) were selected as the analytical line of Mg. 21 soil samples with different concentrations were analyzed, and the calibration curve of the net intensity of atomic line and ion line versus the corresponding concentration were constructed, respectively. And the correlation coefficient was 0.910 and 0.888. For the result, double-spectrum line quantitative analysis method was used to construct the calibration curve for 21 soil samples. The correlation coefficient was increased to 0.950, and the limit of detection was 0.008%. The relative error of 9 soil samples predicted concentration from calibration model was in the range 0.41%～5.32%, with the average error of 1.84%.