复合肥中磷元素的激光诱导击穿光谱多元非线性定量分析

采用激光诱导击穿光谱技术对复合肥中磷元素含量进行了定量分析。通过分析特征谱线的激发能级、跃迁概率和干扰情况，确定255.3和844.6 nm分别为磷元素、氧元素的分析线。实验中对18个复合肥样品进行了测量分析，用14个样品建立磷元素的定标曲线，相关系数r仅为0.83，因此采用多元非线性回归方法进行定量分析，提高测量的准确性。与传统定标曲线相比，在考虑氧元素特征谱线的影响时，LIBS测量值与参考值的相关系数r提高到0.98，测量的相对误差大大减小，仅为0.38%～1.70%。实验结果表明，LIBS技术具有快速分析复合肥中磷元素的潜力。

Quantitative Analysis of P in Fertilizer by Laser-Induced Breakdown Spectroscopy with Multivariate Nonlinear Method

The quantitative analysis of phosphorus in fertilizer was investigated by laser-induced breakdown spectroscopy (LIBS) in this paper. The atomic spectral lines of 255.3 and 844.6 nm for phosphorus and oxygen, respectively, were determined as the optimized line by analyzing the excitation energy, transition probability and interference elements. Eighteen samples were analyzed and fourteen of them were tested to construct the calibration curve of measured concentration of phosphorus, while the linear fitting degree of the calibration curve was 0.83. It should utilize more information of LIBS spectra to construct the multivariate nonlinear regression method, which can improve the measurement accuracy of LIBS. Compared with the calibration method, the correlation coefficient of the prediction concentration of LIBS with reference concentration was 0.98, and the relative measured error was greatly reduced, only in the range of 0.38%～1.70%. It is shown that LIBS has the potential for rapid analysis of phosphorus in fertilizer.