title: Application of dried-droplets deposited on pre-cut filter paper disks for quantitative LA-ICP-MS imaging of biologically relevant minor and trace elements in tissue samples.
abstract: In this work, a novel calibration approach for minor and trace element quantification in LA-ICP-MS imaging of biological tissues is presented. Droplets of aqueous standard solutions are deposited onto pre-cut pieces of filter paper, allowed to dry, and sputtered with a thin gold layer for use as pseudo-internal standard. Analysis of the standards using LA-ICP-MS is performed using radial line-scans across the filters. In contrast to conventionally used preparation of matrix-matched tissue standards, the dried-droplet approach offers a variety of advantages: The standards are easy to prepare, no characterization of the standards using acid digestion is required, no handling of biological materials is necessary, and the concentration range, as well the number of investigated analytes is almost unlimited. The proposed quantification method has been verified using homogenized tissue standards with known analyte concentrations before being applied to a human malignant mesothelioma biopsy from a patient who had not received any chemotherapeutic treatment. Elemental distribution images were acquired at a lateral resolution of 40 μm per pixel, limits of detection ranging from 0.1 μg g(-1) (Mn, Ni, Cu, Zn) to 13.2 μg g(-1) (K) were reached.
authors.affiliation: TU Wien, Institute of Chemical Technologies and Analytics, Vienna, Austria.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Bonta
authors.affiliation: Department of Thoracic Surgery, Comprehensive Cancer Center, Medical University of Vienna, Austria; MTA-SE Molecular Oncology Research Group, Hungarian Academy of Sciences, Budapest, Hungary.
authors.forename: Balazs
authors.initials: B
authors.lastname: Hegedus
authors.affiliation: TU Wien, Institute of Chemical Technologies and Analytics, Vienna, Austria. Electronic address: andreas.limbeck@tuwien.ac.at.
authors.forename: Andreas
authors.initials: A
authors.lastname: Limbeck
mesh_terms: D000368:Aged; D000818:Animals; D001706:Biopsy; D002138:Calibration; D006801:Humans; D007668:Kidney / Q000737:chemistry; D008099:Liver / Q000737:chemistry; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D008654:Mesothelioma / Q000737:chemistry* / Q000473:pathology; D010209:Paper; D012015:Reference Standards; D013552:Swine; D014131:Trace Elements / Q000032:analysis*
chemical_list: D014131:Trace Elements
keywords: Biological specimen; Imaging; LA-ICP-MS; Quantification; Trace elements