Boosting the Pixel Acquisition Rate of Elemental Mapping with Laser Ablation-ICP-Mass Spectrometry to 1000 Hz.

Novel low-dispersion ablation cell designs and highly efficient aerosol transport systems have enabled fast elemental mapping using laser ablation-ICP-mass spectrometry (LA-ICP-MS) at high spatial resolution and its application in various research fields. Nowadays, the fastest low-dispersion setups enable narrow single pulse responses (SPR, duration of the transient signal observed upon a single laser shot), which enhance the signal-to-noise ratio and boost the pixel acquisition rate attainable in elemental mapping applications. In this work, the analytical performance of a nanosecond 193 nm ArF* excimer-based kHz laser in combination with a low-dispersion tube-type ablation cell, coupled to an ICP-mass spectrometer equipped with a time-of-flight (ToF) analyzer, was evaluated. SPR profiles exhibited a duration below 1 ms (defined as full peak width at 10% of the peak maximum, FW0.1M) upon ablation of a NIST SRM 610 glass reference material (0.7 ± 0.1 ms) and a multielement-spiked gelatin droplet standard (0.6 ± 0.1 ms) using a 5 μm laser spot size and matrix-optimized laser energy density. Parameters such as pulse-to-pulse energy stability, linearity of the signal response, oxide ion formation, and elemental fractionation were evaluated. The duration of the SPR profiles determines the maximum achievable pixel acquisition rate, enabling up to 1000 pixels/s with the setup evaluated. As a proof of concept, this is illustrated via quantitative multielemental mapping of a highly primitive chondritic meteorite, displaying a fine mineral texture and heterogeneous elemental distributions, at high spatial resolution and firing only a single shot per pixel.