A New Mapping Protocol for Laser Ablation (with <scp>Fast‐Funnel</scp>) Coupled to a <scp>Time‐of‐Flight</scp> Mass Spectrometer (<scp>LA‐FF‐ICP‐ToF‐MS</scp>) for the Rapid, Simultaneous Quantification of Multiple Minerals
Dany Savard, Sarah Dare, L. Paul Bédard, Sarah‐Jane Barnes
Abstract
Although in situ analysis by LA‐ICP‐MS is considered a rapid technique with minimal sample preparation and data reduction, mapping areas of millimetres in size using a small beam (< 15 μm) can be time consuming (several hours) when a quadrupole ICP‐MS is used. In addition, fully quantitative imaging using internal standardisation by LA‐ICP‐MS is challenging in samples with more than one mineral phase present due to varying ablation rates. A new protocol for the quantification of multiple coexisting phases, mapped at a rate of about 12 mm 2 h ‐1 and a resolution of 12 μm × 12 μm per pixel, is presented. The protocol allows mapping of most atomic masses, ranging from 23 Na to 238 U, using a time‐of‐flight mass spectrometer (ICP‐ToF‐MS, TOFWERK) connected to a 193 nm excimer laser. A fast‐funnel device was successfully used to increase the aerosol transport speed, reducing the time usually required for mapping by a factor of about ten compared with a quadrupole ICP‐MS. The lower limits of detection for mid and heavy masses are in the range 0.1–10 μg g ‐1 , allowing determination of trace to ultra‐trace elements. The presented protocol is intended to be a routine analytical tool that can provide greater access to the spatial distribution of major and trace elements in geological materials.