摘要
为了研究Na元素在水中的检测灵敏度,采用激光诱导击穿光谱检测NaCl溶液中的Na元素。选择NaⅠ589.0nm和NaⅠ589.6nm作为分析谱线,利用配置的六种浓度的NaCl溶液,采用外标法、内标法以及小波变换降噪法,给出了NaCl溶液中Na元素的定标曲线。发现通过内标法获得的定标曲线的线性相关系数r达到0.998,优于外标法(r=0.985),并且优于小波降噪后外标法(r=0.986)。相对外标法而言,小波变换降噪法有效降低了LIBS光谱中的连续背景光谱噪声,使LIBS的RSD从5.68%降至1.61%,从而使LOD值从50.8μg·mL^-1降至19.54μg·mL^-1,内标法选择NaⅠ589.0nm和NaⅠ589.6nm钠原子谱线与内标参考谱线HⅠ656.2nm氢原子谱线强度比值能有效的克服实验条件波动带来的影响,因此,内标法给出的NaCl溶液中Na元素的定标曲线的线性相关系数最大。而对于小波变换降噪处理方法,能够有效的降低LIBS光谱的连续背景带来的噪声,但不能克服实验条件波动对LIBS光谱信息的影响,因此小波变化降噪方法能够提高LIBS的RSD,但对降噪处理后的外标法给出的定标曲线的线性相关系数的提高影响不大。说明内标法有效的提高了检测灵敏度,减弱了实验条件波动带来的影响,定标曲线具有更好的线性相关性。而小波变换降噪处理后有效降低了LIBS光谱中的连续背景光谱噪声,实现LIBS检测限变低。谱线NaⅠ589.0nm为分析谱线得到的RSD和LOD值小于以谱线NaⅠ589.6nm为分析谱线的结果,NaⅠ589.0nm和NaⅠ589.6nm这两谱线的上能级分别为2.104和2.102eV,发现分析谱线的上能级对NaCl溶液中的Na元素的RSD和LOD值有影响,存在上能级大,而RSD和LOD值较小的现象。研究结果表明,LIBS技术可以实现溶液中元素的原位实时检测,并在水污染检测方面受到广泛关注。
In order to study the detection sensitivity of Na elements in water,the Na elements in NaCl solution were detected by laser induced breakdown spectroscopy.Choosing NaⅠ589.0 nm and NaⅠ589.6 nm as analytical spectral lines,we used the NaCl solution with 6 kinds of concentration and adopted external standard method,internal standard method and wavelet transformation noise reduction method to present NaCl solution Na element calibration curve,finding that the linear correlation coefficient r of calibration curve obtained by using internal standard method is 0.998,better than that of calibration curve obtained by using external standard method(r=0.985),and is superior to the external standard method after wavelet noise reduction(r=0.986).In contrast,the wavelet transformation reduced the RSD from 5.68%to 1.61%,thereby reducing the LOD value from 50.8 to 19.54μg·mL^-1.The internal standard method selects the NaⅠ589.0 nm and NaⅠ589.6 nm sodium atomic line and the internal standard reference line HⅠ656.2 nm hydrogen atom line intensity ratio can effectively overcome the impact of experimental conditions fluctuations,therefore,the linear correlation coefficient of the calibration curve of Na element in NaCl solution obtained by using the internal standard method is the largest.For the wavelet transformation noise reduction processing method,the noise caused by the continuous background of the LIBS spectrum can be effectively reduced,and the influence of the experimental condition fluctuation on the LIBS spectral information cannot be overcome.Therefore,the wavelet variation noise reduction method can improve the RSD of the LIBS,but has little effect on-the improvement of the linear correlation coefficient of the calibration curve given by the external standard method after noise processing.It is indicated that the internal standard method effectively improves the detection sensitivity and reduces the influence of fluctuations in experimental conditions.The calibration curve has a better linear correlation.The
作者
林晓梅
郭明
王兴生
高勋
LIN Xiao-mei;GUO Ming;WANG Xing-sheng;GAO Xun(Department of Electronics and Electrical Engineering,Changchun University of Technology,Changchun 130012,China;School of Science,Changchun University of Science and Technology,Jilin 130022,China)
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2019年第6期1953-1957,共5页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(61575030)
国家重大科学仪器开发专项(2017YQ120351)
吉林省科技厅(20180414017GH,20180101283JC)资助
关键词
激光诱导击穿光谱技术
液体射流
定量分析
小波降噪
检测限
Laser induced breakdown spectroscopy(LIBS)
Liquid jet
Quantitative analysis
Wavelet denoising
Detection limit
