用光电双脉冲LIBS技术快速测量水中痕量汞元素  

Rapid Measurement of Trace Mercury in Aqueous Solutions with Optical-Electrical Dual Pulse LIBS Technique

作　　者：张谦[1] 熊威[1] 陈钰琦[1] 李润华[1] 

机构地区：[1]华南理工大学理学院物理系,广东广州510640

出　　处：《光谱学与光谱分析》2011年第2期521-524,共4页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(10874047)资助

摘　　要：用木片吸收水溶液,将水溶液样品转变为固体样品,从而解决用激光诱导击穿光谱(LIBS)技术直接分析水样品所带来的诸多问题,并首次采用光电双脉冲LIBS技术来增强激光等离子体中汞的原子辐射。实验绘制了用单脉冲LIBS技术和光电双脉冲LIBS技术所得到的汞的校正曲线并得出这两种技术中汞的最低检出限分别为2.4和0.3mg.L-1。在现有实验条件下,光电双脉冲LIBS技术与传统的单脉冲LIBS技术相比,其253.65nm处原子辐射信号强度增强了约50倍,汞的检出限降低了一个数量级,一次测量的时间短于5min。由于汞原子辐射随放电时间的延长衰减较慢,增加电脉冲脉宽还可以进一步提高汞原子发射的时间积分强度,从而进一步提高光电双脉冲LIBS技术对汞元素的检测灵敏度。A wood slice was used as absorber to transfer liquid sample to solid sample in order to solve the problems existing in directly analyzing aqueous solutions with laser-induced breakdown spectroscopy（LIBS）.An optical-electrical dual pulse LIBS（OEDP-LIBS） technique was first used to enhance atomic emission of mercury in laser-induced plasma.The calibration curves of mercury were obtained by typical single pulse LIBS and OEDP-LIBS techniques.The limit of detection（LOD） of mercury in these two techniques reaches 2.4 and 0.3 mg·L-1,respectively.Under current experimental conditions,the time-integrated atomic emission of mercury at 253.65 nm was enhanced 50 times and the LOD of mercury was improved by one order,if comparing OEDP-LIBS to single pulse LIBS.The required time for a whole analysis process is less than 5 minutes.As the atomic emission of mercury decays slowly while increasing the delay time between electrical pulse and laser pulse,increasing the electrical pulse width can further enhance the time integrated intensity of mercury emission and improve the detection sensitivity of mercury by OEDP-LIBS technique.

关 键 词：LIBS 汞 水溶液 光电双脉冲 

分 类 号：O433.4[机械工程—光学工程]