• Cn, Borca
• Shaw-Stewart, James
• Günther, D.
• Ha, Wang
• Bodenmiller, Bernd
• Grolimund, Daniel
• Giesen, C.

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.

Topics

• impedance spectroscopy
• dispersion
• thin film
• two-dimensional
• spectrometry
• laser ablation
• inductively coupled plasma mass spectrometry