†Department of Analytical Chemistry, Ghent University, Krijgslaan 281 - S12, B-9000 Ghent, Belgium.
‡Analytical Chemistry Laboratory, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia.
Anal Chem. 2015 Jun 16;87(12):6125-32. doi: 10.1021/acs.analchem.5b00700. Epub 2015 May 22.
In this work, pre- and postacquisition procedures for enhancing the lateral resolution of laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) in two- and three-dimensional (2D, 3D) nuclide distribution mapping beyond the laser beam waist are described. 2D images were constructed by projecting a rectangular grid of discrete LA positions, arranged at interspacings smaller than the dimensions of the laser beam waist, onto the sample surface, thus oversampling the region of interest and producing a 2D image convolved in the spatial domain. The pulse response peaks of a low-dispersion LA cell were isolated via signal deconvolution of the transient mass analyzer response. A 3D stack of 2D images was deconvolved by an iterative Richardson-Lucy algorithm with Total Variance regularization, enabling submicrometer image fidelity, demonstrated in the analysis of trace level features in corroded glass. A point spread function (PSF) could be derived from topography maps of single pulse craters from atomic force microscopy. This experimental PSF allows the approach to take into account the laser beam shape, beam aberrations, and the laser-solid interaction, which in turn enhances the spatial resolution of the reconstructed volume.
在这项工作中，描述了在激光烧蚀 - 电感耦合等离子体质谱（LA-ICPMS）中增强横向分辨率的预和后采集程序，该技术可在激光束腰之外进行二维（2D）和三维（3D）核素分布映射。通过将离散的 LA 位置矩形网格投影到样品表面上，以小于激光束腰尺寸的间隔排列，从而对感兴趣的区域进行过采样，并产生在空间域中卷积的 2D 图像，来构建 2D 图像。通过对瞬态质量分析器响应进行信号解卷积，分离出低色散 LA 池的脉冲响应峰值。通过具有总变差正则化的迭代 Richardson-Lucy 算法对 2D 图像的 3D 堆叠进行反卷积，从而实现亚微米级图像保真度，在对腐蚀玻璃中的痕量特征的分析中得到了验证。可以从原子力显微镜的单个脉冲撞击坑的形貌图中得出点扩散函数（PSF）。这种实验 PSF 允许该方法考虑激光束形状、光束像差和激光-固体相互作用，这反过来又提高了重构体积的空间分辨率。
