Application of a micro-droplet generator for an ICP-sector field mass spectrometer – optimization and analytical characterization

Abstract

A micro-droplet generator (μDG) sample introduction system was coupled to a sector field ICP-MS instrument to investigate the analytical figures of merit with respect to single cell analysis. The sector field instrument was operated for the first time in a fast scanning mode (E-scan) with the shortest time resolution of 100 μs to measure the single droplet time resolved and using the original detector in a pulse counting mode without modification of the existing electronics. For reduction of the droplet diameter a triple pulse mode of the droplet generator was applied and a droplet diameter down to 23 μm has been achieved for this investigation with a 100% transport efficiency of droplets. Signal duration times of single droplets of less than 500 μs have been measured. Overall detection efficiencies in the range of 10⁻³ counts per atom have been achieved and absolute limits of detection range between 120 ag for Fe and 1.1 ag for Mg as a mean value from 1000 droplet events.