Aliasing Artifacts in Multielemental LA-ICP-TOFMS Mapping: An Old Problem Revisited

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Geochemistry

Background:

• Unsynchronized laser pulses and data acquisition in quadrupole LA-ICP-MS cause signal aliasing, leading to inaccurate quantitation and degraded image quality.
• Signal aliasing manifests as low- to medium-frequency alterations in time-averaged signals, not reflecting true analyte concentrations.

Purpose of the Study:

• To investigate and address signal aliasing in LA-ICP-TOFMS.
• To determine optimal acquisition time settings in TOF instruments to mitigate aliasing artifacts.

Main Methods:

• Theoretical simulations of signal acquisition in TOF mass analyzers.
• Experimental mapping of standard reference materials using LA-ICP-TOFMS.

Main Results:

• Exact synchronization between laser pulses and data acquisition is impossible in LA-ICP-TOFMS due to constrained acquisition times.
• Signal aliasing is an inherent issue in LA-ICP-TOFMS, even with acquisition times near the SPR.
• Optimal acquisition time involves a compromise to minimize signal spread while avoiding excessive redundant data.

Conclusions:

• Minimizing signal aliasing in LA-ICP-TOFMS requires careful selection of acquisition time.
• A balance must be struck between reducing signal spread and managing data volume for accurate quantitative analysis and imaging.