用激光诱导击穿光谱技术定量分析土壤中Ba和Sr

利用激光诱导击穿光谱(laser induced breakdown spectroscopy,LIBS)技术检测土壤标准样品中Ba和Sr的含量,用光纤光谱仪探测等离子体冷却过程中的发射谱线,选取BaⅡ455.41nm和SrⅠ460.73nm特征谱线为分析线。为了减小误差,采用Lorenizian函数进行光谱轮廓曲线拟合对数据预处理,提取光谱净强度值。选择多元素谱线强度和作为内标,根据分析线与内标线强度值之比建立定标曲线,Ba和Sr含量与其强度比的线性系数分别达到0.990 0和0.990 6,采用这种强度比定标法对Ba和Sr的含量进行反演,测定Ba和Sr含量值与标准值的相对偏差分别为5.7%和5.1%。

Quantitative analysis of Ba and Sr in soil using laser-induced breakdown spectroscopy

Laser induced breakdown spectroscopy (LIBS) was applied to measure barium and strontium elements in soil. The emission spectrum was emitted as the plasma was cooling off, which was collected and analyzed by fiber spectrometer. Spectral lines of barium (BaII line at 455.41 nm) and strontium (SrI line at 460.73 nm) were separately used for the determining. In order to reduce the error, fitting of the spectra by using Lorenizian function was used, the datum was preprocessed and the net intensity value of the spectra was collected. A signal intensity in the proper range of the characteristic spectrum was chosen as the interior label. A calibration curve was drawn according to the ratio between the value of the analytical line and the interior scaling line. The correlation coefficient between the content and the intensity ratio of Ba and Sr were up to 0.990 0 and 0.990 6. The content of Ba and Sr was inversed by means of the intensity scaling method. As a result, the relative deviations between the content values and the standard values of Ba and Sr were 5.7% and 5.1% respectively.