JR Williams, AE Pillay and S Stephen
Keywords: ICP-MS, biomedical, environmental, pharmaceutical, trace metals.
Abstract: This paper primarily examines the capability of using ablative laser technology to assess the uniformity of distribution of trace elements in highly processed solid pharmaceutical samples. The study investigated elemental profiles in the solid phase, both spatially and depth-wise using a 55 ?m-diameter laser beam coupled to an ICP-MS instrument. Solids were subjected to 213-nm irradiation along a 4-point grid, each point separated by a distance of 1.0 mm. The level of the beam energy was 70%, and the laser was programmed to ablate a depth of 5 ?m at each point, with iterative scanning, recording measurements after each ablation to a total depth of 150 ?m. The experimentally determined laser results showed fluctuations in characteristic metal intensity and, in some cases, ‘hotspots’ (or build-up) were observed. The exact mechanism for this random accumulation of trace metals is not clear, but could be partially attributed to uneven mixing. For purposes of general comparison, total concentrations of elements in the individual solid samples, digested in aqueous media, were also determined. These absolute data reflected elevated levels of some toxic metals, which could be linked to potential environmental and biomedical effects.
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