Sub-microm nanosecond LA-ICP-MS imaging at pixel acquisition rates above 250 Hz via a low-dispersion setup.

The analytical figures of merit of a low-dispersion (ultrafast) ablation cell geometry within the Cobalt ablation chamber, integrated into a nanosecond laser ablation - inductively coupled plasma-mass spectrometer system, are reported on. The system was investigated for its capability for fast high-resolution elemental imaging. A spot of 0.6 microm diameter was achieved on the sample surface by aperture imaging of a 10 microm pinhole. The resulting conical crater (0.6 microm slashed circle x130 nm downward arrow) morphology in a Au-coated glass target and carbon-coated silica wafer was characterized with Atomic Force Microscopy (AFM). The Cobalt ablation chamber is based around a motorized height-adjustable tube cell, which allows modulating the sampling distance, i.e. the distance between the sample surface and the cell inlet in a dynamic manner. This distance was observed to influence the single pulse response (SPR) profile. The variation of the average signal intensity at multiple sample heights within a range of 0.5 mm was <3% RSD. Under optimum conditions, single pulse responses with a full width at 10% of the peak intensity (FW0.1M) of ~ 1 ms can be achieved for 238U, upon ablation of NIST SRM612 glass, effectively opening the way to pixel acquisition rates up to 1 kHz. To demonstrate the potential of this technology, the elemental distribution of Zn in small intestine villi of mice, subjected to a Zn-enriched diet, was imaged using the 0.6 microm spot size, and rapid imaging of a zircon grain cross-section was performed.