Application of gold thin-films for internal standardization in LA-ICP-MS imaging experiments

Abstract

LA-ICP-MS imaging experiments are of growing interest within the field of biosciences. Revealing the distributions of major components as well as trace elements in biological samples can help to understand fundamental biological processes. However, highly variable sample conditions and changing instrumental parameters during measurement time aggravate reliable quantification especially in biological tissues. Normally matrix matched standards used for calibration are scarcely available and the manufacturing process thereof is rather complicated. Thus most experiments reported in the literature only delivered qualitative information on the analyte distributions. The use of appropriate internal standards facilitates the preparation of calibrations even without the utilization of matrix-matched standards. In the presented work an approach for providing reliable quantitative bio-images is proposed using gold thin-layers as an internal standard and patterns printed with commercially available inkjet printers as standards. The method development is based on copper from blue ink as the element of interest. It could be shown that gold standardization compensates instrumental drifts, matrix related ablation differences and day-to-day signal changes. Not only was the quality of the obtained images improved by gold standardization; while the relative standard deviation of the measurements was around 15% before standardization it could be decreased to less than 5% by gold standardization. Also quantitative information could be obtained for samples with unknown analyte concentrations. Depending on the used beam diameter limits of detection in the range of some hundreds ng g(-1) were achieved. The presented method is a promising and easy-to-handle alternative to matrix matched standards for signal quantification.

Atomic spectrometry update: review of advances in atomic spectrometry and related techniques

“…64 The gold standardisation was found to compensate for instrumental dris, matrix related ablation differences and day-to-day signal changes. 64 The gold standardisation was found to compensate for instrumental dris, matrix related ablation differences and day-to-day signal changes.…”

Gelatin gels as multi-element calibration standards in LA-ICP-MS bioimaging: fabrication of homogeneous standards and microhomogeneity testing

“…10 Non-matrix matched calibration standards need to be combined with single/multiple internal standard normalization to correct for elemental fractionation caused by sensitivity drift, matrix effects as well as the difference in ablation yield between samples and standards. This can be achieved via an additional layer containing the internal standard on or under the samples and calibration standards, 11,12 by aspirating a known standard solution into the ablation cell or directly in front of the torch, or by using no internal standard but total consumption of a sectioned sample and calibration standard. 13 Commonly the quantification relies on in-house prepared calibration standards as described in a recent comprehensive review by Limbeck et al 3 In an often followed protocol by Hare et al 14 standards are tuned to the specific tissue under study by spiking similar homogenized tissue material with the elements of interest followed by cryo-fixing and -sectioning.…”

Analysis of single fly ash particles using laser ablation ICP-MS – an approach achieving lateral elemental distribution information via imaging

“…Instrumentation A commercially available Nd:YAG nanosecond laser ablation system (NWR213, ESI, USA) equipped with a standard, fastwashout-cell provided by the manufacturer and suitable for imaging applications 31,[38][39][40] was used to ablate the samples. For analysis, the generated sample aerosol was transferred to a quadrupole ICP-MS (iCAP Q, Thermo Fisher Scientic, Bremen, Germany) using PTFE tubing.…”

“…Alternatively, for imaging purposes the prepared particle cross sections were analyzed by covering the whole surface area with adjacent line scans; laser beam diameters of 3 and 5 mm were used. The intensity data recorded for the measured line scan patterns were exported as csv les and processed with ImageLab (v.1.02, Epina GmbH, Pressbaum, Austria) as suggested by Bonta et al 38 All 2D maps had squared pixels with pixel sizes of 3 Â 3 or 5 Â 5 mm 2 , respectively.…”