水体重金属多元素LIBS测量连续背景光谱去除方法研究

Study on Removing Method of Continuous Background Spectrum in LIBS of Multi-Element Heavy Metals in Water

连续背景光谱是影响水体重金属多元素激光诱导击穿光谱(LIBS)定量测量的重要因素,依据背景光谱变化缓慢和特征谱线半峰全宽窄的特性,研究了滑动窗口积分斜率算法去除连续背景的方法。设置合适的窗口宽度和变化率阈值识别背景光谱和特征峰位,对窗口内的背景进行赋值操作,完成整个背景光谱的提取。实验结果表明,Pb、Cu元素特征信号的信背比是背景去除前的5.7倍和1.95倍,特征信号的相对标准偏差分别降低了2%和2.5%。滑动窗口积分斜率算法是一种稳定有效的LIBS光谱背景去除方法,为其他光谱分析技术中连续背景的去除提供了参考。

Continuous background spectrum is an important influencing factor of laser induced breakdown spectrometry（LIBS）quantitative measurement of multi-element heavy metals in water.According to the characters that the background spectrum changes slowly and full width at half maximum of characteristic spectral lines is narrow,the sliding window integral slope algorithm for removing continuous backgrounds is studied.Seting appropriate window width and slope threshold to identify the background spectrum and characteristic peaks,the assignment is carried out on window background,the background spectrum is extracted completely.The experimental results show that the signal-to-background ratios of plumbum and copper are 5.7 times and 1.95 times respectively to that before removing the background,the relative standard deviations are reduced by 2% and 2.5% respectively.The sliding window integral slope algorithm is a stable and effective method for removing backgrounds in LIBS,and also provids an reference for removing backgrounds in other optical spectrum analysis technology.