激光诱导击穿光谱结合自由定标法同时定量分析玻璃主要元素

建立激光诱导击穿光谱结合自由定标法快速定量分析玻璃中主要元素Si和Ba的方法.采用由调Q脉冲Nd:YAG激光器、中阶梯光栅光谱仪和ICCD检测器等组成的激光诱导击穿光谱系统采集4种标准玻璃样品的激光诱导击穿光谱.提取光谱信息,结合自由定标法建立样品中Si和Ba的玻尔兹曼曲线,计算获得4种玻璃样品中Si和Ba的含量.Si含量分析相对误差在4.96%~10.12%之间,标准差在0.38%~1.29%之间,Ba含量分析相对误差在4.07%~9.62%之间,标准差在0.54%~1.70%之间.T检验表明,测量值与实际值无显著差异.     

基于激光诱导击穿光谱技术定量分析食用明胶中的铬元素

利用激光诱导击穿光谱技术对食用明胶样品中的铬元素进行定量分析.采用Nd:YAG脉冲激光器三倍频输出的355 nm激光诱导击穿食用明胶产生激光等离子体,测量等离子发射光谱.实验数据表明:使用内标法定量分析食用明胶样品中铬元素浓度分别为10—200 ppm(1 ppm=10-6)时,铬元素含量与分析谱线(CrI:245.43 nm)强度之间具有很好的线性关系.分析了光谱探测延迟时间对明胶中铬元素激光诱导击穿光谱的影响,利用信号强度与信噪比获得了优化的光谱探测延迟时间实验参数.     

基于激光诱导击穿光谱技术的铝合金成分定量分析

利用Nd:YAG激光器输出的532nm激光束对位于空气中的标准变形铝合金样品进行烧蚀产生了激光诱导等离子体.对测量的230—440nm波长范围的光谱进行了谱线标定,同时基于自由定标方法对样品成分进行了定量分析,确定了样品中的元素含量.分析结果与标准值具有较好的一致性.     

土壤重金属铬元素的激光诱导击穿光谱定量分析研究

利用Nd ∶YAG脉冲激光器(波长:1064 nm)作为光源,在实验室自然大气环境下诱导产生土壤激光等离子体,通过等离子体原子发射光谱法定量分析了国家标准土壤样品中元素Cr的含量.实验上研究了在最佳实验条件下土壤中Cr的LIBS分析谱线,测定了Cr元素的定标曲线.实验结果表明,Cr元素浓度在(60—400)×10^-6范围内,元素含量与光谱线强度之间有较好的线性关系;元素Cr浓度分析测量的相对标准偏差(RSD)为7.89%,定量分析结果与标准值的相对偏差为5.3%,Cr元素的检测限为1 关键词： 土壤污染 定量分析 激光诱导击穿光谱 定标曲线     

PLS算法在激光诱导击穿光谱分析炉渣成分中的应用

炉渣成分的实时在线检测是目前金属冶炼企业迫切需求的一项技术.本文利用激光诱导击穿光谱技术结合偏最小二乘回归模型对炉渣中的CaO、MgO、Al2O3和Fe进行定量分析.采用背景修正和基于等离子体成像强度的谱线归一化法对光谱进行预处理,有效提高了光谱强度的准确性和稳定性.利用25块已知成分的炉渣样品建立偏最小二乘回归定量分析模型,并用其预测另外5块样品成分.CaO、MgO、Al2O3和Fe预测结果的平均相对误差分别为4.7%、11.5%、17.9%和12.5%.实验结果表明,激光诱导击穿光谱结合偏最小二乘回归方法可实现炉渣成分实时在线检测.     

应用激光诱导击穿光谱检测土壤中的铅

应用激光诱导击穿光谱技术对模拟土壤中Pb进行快速定量分析。该模拟土壤由PbCl₂,CaCO₃,SiO₂,KBr化学纯试剂制备而成。通过实验得到信噪比随延时的增大呈先增后减的变化规律。利用实验光谱图建立了Pb含量的定标曲线。定量分析研究得到：该方法用于Pb含量定量分析的平均相对误差为8.33%,最低检测限为89μg/g。实验结果验证了激光诱导击穿光谱技术用于土壤中Pb含量测量的能力。     

土壤中微量元素锰的激光诱导击穿光谱定量分析

采用激光诱导击穿光谱技术分析安徽怀远农亢农场土壤样品中微量元素Mn的含量分布情况。实验中选取403.1 nm作为Mn元素的分析线为,土壤中基体元素Fe作为内标元素,选取的分析线为407.2 nm。选取10个土壤样品分别用传统定标方法和内标法建立定标曲线,并对4个待测样品浓度进行预测。实验结果表明,传统定标方法建立的定标曲线的拟合相关系数r为0.954,检测限为93 mg·kg-1,待测样品的测量相对误差最大为5.72%;而采用内标法建立的定标曲线的拟合相关系数r为0.983,测量的相对误差减小到4.1%,检测限为71 mg·kg-1。说明采用LIBS技术对土壤中微量元素Mn检测的可行性,同时,内标法一定程度上可提高测量的精确性。     

用激光诱导击穿光谱技术定量分析油漆中的有害重金属

很多轻工业产品需要用到油性油漆,其中的重金属元素的含量是否超标将会直接影响到产品质量及其安全性.因此发展轻工产品中重金属含量的快速检测技术,对促进国民经济的发展和保障消费者生命安全具有重要的意义.我们利用激光诱导击穿光谱技术实现了对油漆中有害重金属含量的快速定性和定量分析.通过观测激光等离子体中重金属原子辐射强度可以定性测量重金属含量的大体水平.然后,在相同检测条件下,将已知浓度的标准样品作为参考,制定出各元素的校正曲线,使用外标法,就能够实现定量分析.对Pb、Cr、Cd三种有害重金属元素,目前检出限分别达到9、3.5和23ppm的水平,分析相对误差小于10%,单次测量时间短于2分钟.汞的结果不太理想,检测灵敏度相对偏低,与其原子辐射寿命较短有关.我们将采取脉冲放电延长汞原子辐射弛豫时间的措施来改进汞元素的分析灵敏度,使其达到较高水平.     

激光诱导击穿光谱技术定量分析钢铁合金中痕量Mo元素实验研究

探索在内标物谱线选择受限情况下利用激光诱导击穿光谱(LIBS)技术进行定量分析的可行方案,并应用到复杂钢铁合金中痕量金属元素钼(Mo)的检测分析中.实验中烧蚀激光波长为532 nm,LIBS信号的采集通过光栅单色仪、(2CD、Boxcar和PMT来完成.对Mo的550.649,553.305和557.045 nm三条原...     

基于激光诱导击穿光谱技术对钢中Mn和Cr元素的定量分析

采用激光诱导击穿光谱分析技术对钢样中锰、铬两种微量元素的含量进行了测量.实验研究发现,最优取样的延迟时间为2.0μs,最佳激光光束聚焦位置和光谱收集探头分别位于样品表面以下3.5mm和表面以上1.5mm处.以Mn Ⅰ:403.07 nm和Cr Ⅰ:427.48 nm作为分析线,分别采用传统定量分析和内定标的方法对钢样中...     

Characterization of inorganic species in coal by laser-induced breakdown spectroscopy using UV and IR radiations

In this work, the capability of laser-induced breakdown spectroscopy for process control in a thermal power plant is presented through quantitative compositional characterization of the coal used for combustion. Laser-induced emission signal of seven samples with a range of concentrations was calibrated for quantification purposes. The eighth sample was subsequently analyzed five times as unknown in order to determine the precision and accuracy of the measurements. Two modes of operation, dynamic and static and two laser wavelengths, 1064 nm and 355 nm were employed in this study for comparison. The results revealed that UV wavelength provided better results than IR radiation in terms of accuracy for the quantification of inorganic species in coal after the comparison with conventional atomic absorption spectrometry characterization.     

用激光感生击穿光谱对大气进行定量分析

研究将激光感生击穿光谱技术用于元素定量分析的可行性。利用Nd∶YAG激光器发出的激光与一个大气压下的空气相互作用产生激光等离子体，等离子体的光经单色仪分光后转化为电信号进入计算机，存储了600～800nm的等离子体光谱数据。利用自由定标模型对等离子体进行了分析。在延迟时间8μs、采样门宽0.4μs时，利用二维波尔兹曼平面得到了大气等离子体处于局部热平衡时的温度（1.62×10K）。在假设空气全部由N和O组成的条件下由自由定标模型得到了空气中氧的含量（20.75%）和氮的含量（79.25%）。试验结果与实际吻合得很好。实验证实了用激光感生击穿光谱对大气进行定量分析是可行的，为大气污染监测研究和试验工作奠定了基础。     

Laser ablation of powdered samples and analysis by means of laser-induced breakdown spectroscopy

The presented work proves the capacities of laser-induced breakdown spectroscopy (LIBS) as a fast, universal, and versatile technique for analysis of complex materials as ceramics. This paper reports on the analysis of ceramic raw materials (brick clays and kaolin) submitted to laser ablation in the form of pressed pellets. Spectrographic study was provided by standard single-pulse LIBS technique and orthogonal reheating double-pulse LIBS. It was found that both methods are comparable in terms of analytical performance, if adequate experimental parameters and signal detection systems are used.     

A review of laser-induced breakdown spectroscopy signal enhancement

A review of the methods of signal enhancement in laser-induced breakdown spectroscopy (LIBS) is presented. Conventional LIBS suffers from disadvantages of low sensitivity and high limits of detection compared with other analytical techniques, such as inductively coupled plasma mass spectrometry. During the last two decades, various methods have been applied to LIBS in order to realize highly quantitative and qualitative analysis. Current approaches include double-pulse excitation, spatial or magnetic confinement, spark discharge, etc. Different configurations of experimental setups and conditions are suggested for the realization of these improved techniques, while various parameters influence significantly on the enhancement effect. With the aim to study the laser ablation process and characterize the effectiveness of each method, several parameters such as plasma volume and emission intensity are reviewed. Several suggestions are proposed to explain the mechanism of each enhancement method. These modified techniques have been applied on various materials and fields.     

无机爆炸物及其主要成分的激光诱导击穿光谱实验研究

以一种常见的无机爆炸物——黑火药及其主要成分硝酸钾作为研究对象,硝酸钠样品作为参照物,使用1 064nm调Q激光器作为光源,进行实验研究。获得了不同环境气体(空气和氩气)中三种样品的击穿诱导等离子体光谱,在不同延迟条件下获得了三种样品的时间分辨谱,并分析了三种样品的O/N谱线强度比值随延时的变化,得出在延时596ns时,O/N比值达到最大值。     

Detection of explosives with laser-induced breakdown spectroscopy

Our recent work on the detection of explosives by laser-induced breakdown spectroscopy (LIBS) is reviewed in this paper. We have studied the physical mechanism of laser-induced plasma of an organic explosive, TNT. The LIBS spectra of TNT under single-photon excitation are simulated using MATLAB. The variations of the atomic emission lines intensities of carbon, hydrogen, oxygen, and nitrogen versus the plasma temperature are simulated too. We also investigate the time-resolved LIBS spectra of a common inorganic explosive, black powder, in two kinds of surrounding atmospheres, air and argon, and find that the maximum value of the O atomic emission line SBR of black powder occurs at a gate delay of 596 ns. Another focus of our work is on using chemometic methods such as principle component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) to distinguish the organic explosives from organic materials such as plastics. A PLS-DA model for classification is built. TNT and seven types of plastics are chosen as samples to test the model. The experimental results demonstrate that LIBS coupled with the chemometric techniques has the capacity to discriminate organic explosive from plastics.     

第十五届全国原子与分子物理学术会议: 用激光诱导击穿光谱技术定量分析油漆中的有害重金属

很多轻工业产品需要用到油性油漆，其中的重金属元素的含量是否超标将会直接影响到产品质量及其安全性。因此发展轻工产品中重金属含量的快速检测技术，对促进国民经济的发展和保障消费者生命安全具有重要的意义。我们利用激光诱导击穿光谱技术实现了对油漆中有害重金属含量的快速定性和定量分析。通过观测激光等离子体中重金属原子辐射强度可以定性测量重金属含量的大体水平。然后，在相同检测条件下，将已知浓度的标准样品作为参考，制定出各元素的校正曲线，使用外标法，就能够实现定量分析。对Pb、Cr、Cd三种有害重金属元素，目前检出限分别达到9、3.5和23ppm的水平，分析相对误差小于10%，单次测量时间短于2分钟。汞的结果不太理想，检测灵敏度相对偏低，与其原子辐射寿命较短有关。我们将采取脉冲放电延长汞原子辐射弛豫时间的措施来改进汞元素的分析灵敏度，使其达到较高水平。     

Laser-induced breakdown spectroscopic studies of marbles

We present laser-induced breakdown spectroscopic studies of variety of marbles extracted from Quetta region of Boluchistan, Pakistan using a Nd:YAG laser (532 nm) in conjunction with LIBS 2000 detection system. The emission spectra of Onyx (white spot) and Quetta Green Marble samples have been recorded as a function of laser irradiance. The elemental composition and their relative abundance in each sample are fond to be quite different. In Onyx (white spot), calcium dominates while in the Quetta Green marble magnesium is the dominant element. In addition the effect of the laser irradiance on the emission intensity, width and shift of the transition lines have been studied.     

Characteristics of solid aerosols produced by optical catapulting studied by laser-induced breakdown spectroscopy

Optical catapulting (OC) constitutes an effective method to transport small amounts of different materials in the form of a solid aerosol. In this report, laser-induced breakdown spectroscopy (LIBS) is used for the analysis of those aerosols produced by OC. For this purpose, materials were catapulted using a Q-switch Nd:YAG laser. A second Q-switch Nd:YAG laser was used for LIBS analysis of the ejected particles. Data processing of aerosols was conducted using conditional data analysis. Also, the standard deviation method was used for the qualitative identification of the ejected particles. Two modes of interaction in OC (OC with focused or defocused pulses) have been evaluated and discussed. LIBS demonstrates that the distribution (spreading) of the ejected particles along the propagation axis increased as a function of the interpulse delay time. The mass density and the thickness of the target also play an important role in OC-LIBS.