土壤钾元素的激光诱导击穿光谱定量检测分析

Quantitative Measurement and Analysis of Potassium in Soil Using Laser-Induced Breakdown Spectroscopy

实现土壤中钾元素含量的快速、现场测量对农田施肥与农业生产管理具有重要意义。利用波长为1064nm的Nd…YAG脉冲激光器作为激发光源,以宽光谱范围、高分辨率的中阶梯光栅光谱仪和高灵敏度的增强型电荷耦合器件(ICCD)作为光谱分光和检测器件,研究土壤中钾元素的激光诱导击穿光谱特性。实验中以钾元素的769.90nm谱线作为分析线,确定探测最佳延时为1μs,最佳检测门宽为5.2μs,钾元素质量分数的检测限为0.006858%,得到土壤样品定标曲线,且预测值与真实值相对误差小于5%。通过对12种不同基体类型的标准土样进行检测分析,结果表明,在实际的定量检测中需针对不同基体类型土壤样品进行分别标定。该研究结果为土壤钾元素的快速、现场定量检测提供了参考。

It has great significance to achieve the fast, in-situ measurement of potassium content in soil to the fertilization in farmland and agricultural production management. The spectroscopy emission characteristics of potassium in soil are studied based on laser-induced breakdown spectroscoy techinque with a 1064 nm wavelength Nd.＇YAG laser as the excitation source, the echelle spectroscopy with high resolution and wide spectral range as the spectral separation device and the intensified charge coupled device （ICCD） as the spectral detection device. With the spectral line of 769.90 nm as the analytical line, the best detection delay time is 1 ~s, gate time is 5.2 /~s, and the limit of detection is 0. 006858 %. The calibration curve of soil samples is obtained. While the relative error between the predicted value and true value is within 5 %. 12 different types of soil with different matrix effects are measured. The result shows that, for the actual quantitative measurement of soil samples with different matrix types, they need to be calibrated respectively. The research result provides a reference for the fast, in-situ quantitative measurement of potassium in soil.