High-resolution elemental bioimaging of Ca, Mn, Fe, Co, Cu, and Zn employing LA-ICP-MS and hydrogen reaction gas
- Publication Type:
- Journal Article
- Analytical Chemistry, 2012, 84 (15), pp. 6707 - 6714
- Issue Date:
Imaging of trace metal distribution in tissue sections by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is typically performed using spatial resolutions of 30 μm2and above. Higher resolution imaging is desirable for many biological applications in order to approach the dimensions of a single cell. The limiting factor for increasing resolution is sensitivity, where signal-to-noise ratios are poor due to inherent background spectral interferences and reduced sample volume with decreasing laser beam diameter. Several prominent spectral interferences are present for a number of biologically relevant isotopes, including the40Ar16O+spectral interference on56Fe+. We examined if H2as a reaction gas could improve the analytical performance of imaging experiments for a range of masses with spectral interferences. At low (<1 mL min-1) H2flow rates, greater spectral interference due to H+adducts was observed for55Mn,57Fe, and59Co. At higher flow rates of up to 3 mL H2per minute, the spectral interferences were reduced leading to improvement in limits of analysis for masses with O- and N-based polyatomic interferences. Enhanced sensitivity with the reaction cell allowed construction of high resolution (6 μm2) imaging of56Fe in the mouse brain that approached the dimensions of single cells. © 2012 American Chemical Society.
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