Ink jet patterns as model samples for the development of LA-ICP-SFMS methodology for mapping of elemental distribution with reference to biological samples

Abstract

Atomic spectrometry techniques capable of micrometre scale resolution such as laser ablation inductively coupled plasma mass spectrometry and micro X-ray fluorescence methods are increasingly employed for mapping in situ element distributions in various specimens, which are displayed as 2D images. One important application of this technology is the analysis of biological tissues from animal models or human subjects in support of studies of diseases linked to changes in metal homeostasis. Biological tissue samples with known element distribution at sub-millimetre scales are not currently available, limiting method development and systematic studies of performance. We used an ink jet printer with copper-containing cyan ink to create various line and 2D patterns. Copper concentration was controlled by varying the colour density (transparency) of the image whilst features from 100 μm to > 1 mm were employed. Good agreement was observed between the printed patterns and LA-SN-ICP-SFMS images. Precision improved with increasing feature size and Cu concentration from around 40% (100 μm, 60 ng cm⁻² Cu) to 3% (>1 mm, 250 ng cm⁻² Cu). Features < 500 μm in size, however, showed lower signal intensity than larger features.