氧化镁是水泥中要求准确测定的主要物质之一。利用激光诱导击穿光谱(LIBS)技术对普通硅酸盐水泥样品进行了等离子体光谱分析。选择Mg I 517.2nm特征谱线作为分析线,测量了不同激光能量下的光谱信号强度以及对应的信噪比,确定了最佳激光能量为40mJ。为减小实验误差,将Mg 517.2nm的光谱强度和516~520nm的光谱强度积分之比作为内标,建立了MgO质量分数测定的定标曲线,定标曲线的线性系数达到了0.9959。采用循环反演的方法检测了MgO定量分析的测量精度,最大相对偏差和平均相对偏差分别为5.9%和2.48%,LIBS对水泥样品中的MgO质量分数的检测限达到了0.51%。 Magnesia is one of the major requirements for accurate determination of cement in cement. Plasma spectroscopy analysis of ordinary Portland cement samples was performed using laser induced breakdown spectroscopy (LIBS). The characteristic line of Mg I 517.2nm was selected as the analytical line. The spectral signal intensity and corresponding signal-to-noise ratio of different laser energy were measured. The optimal laser energy was 40mJ. In order to reduce the experimental error, the calibration curve of MgO mass fraction was established by using the ratio of the spectral intensity of Mg 517.2nm and the spectral intensity of 516 ~ 520nm as the internal standard. The linearity coefficient of the calibration curve reached 0.9959. The measurement accuracy, the maximum relative deviation and the average relative deviation of MgO quantitative analysis were 5.9% and 2.48%, respectively. The detection limit of MgO mass fraction in cement samples by LIBS was 0.51%.