Influence of laser ablation parameters on trueness of imaging

Abstract

Influence of laser ablation conditions on limit of detection, spatial resolution and time of analysis was studied for laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) applied to elemental mapping. Laser repetition rate and laser fluence were investigated in tapeworm thin section to attain optimum ablation rate, yielding appropriately low detection limit which complies with elemental contents in the tissue. Effect of combinations of laser spot size and scan speed on relative broadening (Δwrel) of image of the ablated pattern (line) was investigated with the aim to quantify the trueness of imaging. Ink lines printed on paper were employed for the study of influence of spot size and scan speed on limit of detection, relative broadening of elemental image and duration of elemental mapping. An uneven distribution of copper in a printed line (coffee stain effect) was observed. The Δwrel is strongly reduced (down to 2%) at low scan speed (10μms−1) and laser spot diameter of 10μm but resulting in unacceptably long time of mapping (up to 3000min). Finally, tapeworm thin-section elemental maps (4mm×5mm) were obtained at the laser spot diameter of 65μm and the scan speed of 65μms−1 within 100min. A dissimilar lateral distribution of Pb was observed in comparison with that of Cu or Zn due to different pathways of element uptake.