title: Fast chemical imaging at high spatial resolution by laser ablation inductively coupled plasma mass spectrometry.
abstract: In recent years, chemical imaging was prognosticated to become one of the key analytical applications for laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). However, moderate spatial resolution and the associated measurement time required for a larger sampling area, have restricted this versatile, high sensitivity technique from being routinely used in two-dimensional chemical imaging. This work describes the development and investigation of a low dispersion sample chamber (tube cell), which allows improvement of the imaging capabilities by reduction of the single LA shot duration to 30 ms (full width at 1% maximum). The new tube cell is based on a constant laminar flow and a well-controlled delivery of the laser-ablated aerosol into the transport system, leading to minimized tailing of the aerosol washout and helping to separate the signals even at repetition rates as high as 20-30 Hz. To demonstrate the improved imaging capabilities, microstructured metallic thin film patterns were analyzed at a spatial resolution of a few micrometers. The LA-ICP-MS results obtained were comparable to Synchrotron-based micro-X-ray fluorescence (SR-microXRF). The suitability of the newly designed cell for multielement acquisitions was demonstrated using a simultaneous ICP-Mattauch-Herzog-MS. Finally, the novel laser ablation cell was applied to image the distribution of a metal-tagged biomarker in a thin section of breast cancer tissue. This application demonstrates that the technique is able to produce subcellular (~1 μm) spatial resolution, which is crucial for morphological assessment in cancer diagnostics.
authors: Trace Element and Micro Analysis Group, ETH Zürich , Wolfgang-Pauli-Str. 10, 8093 Zurich, Switzerland.
authors: Hao A O
authors: HA
authors: Wang
authors: Daniel
authors: D
authors: Grolimund
authors: Charlotte
authors: C
authors: Giesen
authors: Camelia N
authors: CN
authors: Borca
authors: James R H
authors: JR
authors: Shaw-Stewart
authors: Bernd
authors: B
authors: Bodenmiller
authors: Detlef
authors: D
authors: Günther
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology; D005260:Female; D006801:Humans; D053685:Laser Therapy; D007834:Lasers; D013058:Mass Spectrometry / Q000379:methods*