Research On Developing Atomic Spectral Analysis Of Soild Samples By Laser Ablation

Laser ablation enables direct analysis of solid samples without the tedious sample preparation process.Laser induced breakdown spectroscopy(LIBS)is an atomic emission spectroscopy technique that analyzes optical emission from the induced plasma by laser ablation.Laser ablation-inductively coupled plasma-mass spectrometry(LA-ICP-MS)is a method using a pulsed laser beam ablates a tiny portion of mass from a sample and directly transport the particles into inductively coupled plasma mass spectrometry by carrier gas purge.As elemental analysis of solid samples,LIBS and LA-ICP-MS have their own advantages and are widely applied in the analysis of geochemical materials,metal samples,biological samples and so on.However,the accuracy of analysis by LIBS or LA-ICP-MS is affected by calibration method and the ablation process which contains complex reactions.The research contents of this paper include the following aspects:(1)The trace elements in human nails were analyzed using LIBS.The operation parameters of laser ablation energy,spectrum delay time,gate width,number of shot count were optimized,and the effect of ambient atmosphere on signal intensity was discussed.Among the 4 groups of nail samples measured by LIBS,the signal intensity of K,Ca,Na,Mg,Al,Si,Fe has a positive correlation with the corresponding element concentration obtained by ICP-AES after sample digestion,which demonstrate that LIBS as a diagnostic tool can be applied to assess human health.(2)Dried droplet calibration approach by LA-ICP-MS was developed.The "coffee ring"phenomenon in dried droplets was suppressed by optimizing the amount of a surfactant,Pluronic F-127,added into the calibration solutions and the drying temperature.The analyzed sample was used as the support of calibration solutions.Then the dried droplet residual areas with different elemental concentrations under optimized conditions can be formed on the corresponding sample surface,which realizes matrix matching.The multi-line ablation mode was used to obtain the corresponding signal intensity at the dried droplet residual areas,and the elemental concentrations in the sample were determined based on the standard addition method.(3)The dried droplet calibration approach using LA-ICP-MS was applied to analyze several inorganic non-metallic materials such as yttrium aluminum garnet(YAG)ceramic.BaF2 crystal,and NIST SRM 612 glass.The results obtained by the method agree well with the results obtained by inductively coupled plasma atomic emission spectrometry(ICP-AES)or inductively coupled plasma atomic mass spectrometry(ICP-MS)and certified values,which will help improve and enhance the material properties.