Single-Pulse Response LA-ICP-MS Imaging with Quadrupole Instrumentation: Theoretical Considerations and Practical Assessment.

Recent instrumental developments in LA-ICP-MS, such as rapid response cells that significantly reduce the washout and the introduction of high-repetition rate lasers, have greatly impacted the field. To fully take advantage of these developments, improvements on the ICP-MS side were necessary. This was achieved by establishing ICP-TOF-MS instruments enabling simultaneous multielement detection suitable for recording the short transient signals generated by modern rapid response cells. These developments enabled a new operational mode for imaging called the single-pulse response (SPR). Nevertheless, quadrupole-based ICP-MS (ICP-Q-MS) instruments are still the most prevalent instrument type nowadays. Even though it provides many benefits, SPR-based imaging has not yet been applied to ICP-Q-MS due to the sequential / detection. However, recent developments enabling shorter dwell times and settling times of ICP-Q-MS systems make a SPR-based imaging approach feasible. In this work, we investigate the potential and limitations of SPR-based imaging using ICP-Q-MS. Therefore, we investigate the relationship between the cycle time and the signal stability by evaluating Ag/Ag while ablating NIST SRM 612. With the results derived, theoretical considerations about the relationship between the peak width, laser repetition rate, and dwell times can be confirmed. In the next step, the effects of different dwell times on image quality and image artifacts are evaluated by imaging a test structure. Finally, the applicability of the SPR-based LA-ICP-Q-MS imaging approach is demonstrated for life science applications by showing SPR multielement measurements of cell samples, detecting 4 elements with a pixel acquisition rate of 100 Hz.