土壤重金属铬元素的激光诱导击穿光谱定量分析研究

Quantitative analysis of chrome in soil samples using laser-induced breakdown spectroscopy

利用Nd:YAG脉冲激光器(波长:1064nm)作为光源,在实验室自然大气环境下诱导产生土壤激光等离子体,通过等离子体原子发射光谱法定量分析了国家标准土壤样品中元素Cr的含量.实验上研究了在最佳实验条件下土壤中Cr的LIBS分析谱线,测定了Cr元素的定标曲线.实验结果表明,Cr元素浓度在(60—400)×10-6范围内,元素含量与光谱线强度之间有较好的线性关系;元素Cr浓度分析测量的相对标准偏差(RSD)为7.89%,定量分析结果与标准值的相对偏差为5.3%,Cr元素的检测限为16.5×10-6;内标法得到的相对偏差为2.7%,说明内标法可提高测量的精确性;利用相同土壤类型做定标曲线得到的定量分析结果的相对偏差为8%.

We quantitatively analyze the content of element Cr in the national standard soil samples by the method of plasma atomic emission spectroscopy,through using Nd：YAG（Wavelength：1064 nm） laser as an excitation source to induce soil plasma in ambient environment of the laboratory.The calibration curve of element Cr is measured by studying the characteristics of laser-induced breakdown spectroscopy of element Cr in soil under optimal conditions.The experimental results demonstrate that the element content（60—400） × 10-6 and the spectral line intensity are in good linear relation,and the relative standard deviation of element analysis of concentration measurement from the standard value is 7.89%.The relative deviation of the quantitative analytic result from the standard value is 5.3%,and the detection limit of Cr in soil is 16.3 × 10-6.The relative deviation by the internal standard method is 2.7%,which indicates that the internal standard method can improve the accuracy of the measurement.Using the same type of soil to achieve the calibration curves,the relative deviation by the quantitative analysis is 8%.