内标法在激光诱导击穿光谱测定煤粉碳含量中的应用

采用激光诱导击穿光谱(laser-induced breakdown spectroscopy，LIBS)技术测量煤粉的元素含量。将高能激光束聚焦在煤粉表面形成样品的高温等离子体，用光纤光谱仪探测等离子体冷却过程中的发射谱线以测定煤粉的元素种类和含量。应用内标法定量分析煤粉C含量，根据测量原理搭建了实验平台，选取化学纯试剂C6H7NO3S、C和SiO2配制的8个混合样品作为标准样，分别进行LIBS实验。依据内标法原理，以Si为内标元素，建立了C含量的定标曲线，并利用该曲线对烟煤煤粉样C进行了定量分析。结果显示，LIBS内标法测定煤粉C含量的相对误差为1.46%，验证了内标法应用于LIBS测定煤粉元素含量的可行性。

Determination of Carbon Content in Pulverized Coal With Laser-induced Breakdown Spectroscopy by Internal Standard Method

Laser-induced breakdown spectroscopy (LIBS) was applied to measure the elements in pulverized coal. An intense laser radiation was focused on the surface of sample to generate a plasma plume which vaporized a small amount of pulverized coal. The emission spectrum emitted as the plasma cooling off, which contained the information of elemental species and concentration in coal, was collected and analyzed by fiber spectrometer, and internal standard method based on carbon element quantitative technique was introduced. An experiment apparatus was set up according to the principle of analysis technique. Experimental studies were carried out separately, with the standard samples which were made of chemical C6H7NO3S, C and SiO2. According to the internal standard method, and with silicon element as internal standard element, calibration curve of carbon element were constructed for quantitative determination. Afterwards, carbon element in pulverized coal sample was analyzed with the calibration curve. From the experiment results for quantitative analysis of carbon content of pulverized coal, the analysis accuracy with relative error is 1.46%, which proved that the internal standard method using in the pulverized coal quantitative analysis by laser-induced breakdown spectro- scopy is applicable.