Evaluation of measurement uncertainty in the elemental analysis of sintered silicon carbide using laser ablation in liquid—inductively coupled plasma mass spectrometry with external calibration and isotope dilution

Abstract

The goal of this study was to evaluate the uncertainty of elemental analytical methods that use laser ablation in liquid (LAL) as a pretreatment. After LAL sampling of silicon carbide (SiC), trace impurities were quantified using inductively coupled plasma-sector field mass spectrometry (ICP-SFMS) with external calibration (EC). The expanded uncertainty (k = 2) of the concentrations was less than 10 %. To obtain more precise values, the Ti, the element homogeneously distributed on the sample surface of SiC, was quantified using ICP-SFMS with isotope dilution mass spectrometry (IDMS). The expanded uncertainty (k = 2) was reduced to 3.4 %. The smaller uncertainty associated with IDMS reflected the fact that measuring the isotope ratio of the same element with IDMS and high-speed isotope measurements at 10-ms intervals reduced the variability of signal intensities, the primary source of uncertainty, more effectively than EC. Moreover, the combination with ID improved the sample amount-dependent unrepeatability in pretreatment.