Strategies for avoiding saturation effects in ESI-MS

Abstract

All instruments with detectors are prone to saturation effects at high concentration, and mass spectrometers are no exception. The very high sensitivity of mass spectrometry makes the onset of saturation occur at lower concentrations than other methods, and in cases where the analyte of interest is very reactive, concentrations at which saturation can be problematic may be necessary in order to ensure decomposition is mitigated. Indications that saturation is occurring are provided, and some data processing strategies are outlined, followed by a range of detuning strategies that can be employed to reduce saturation effects in the context of electrospray ionization mass spectrometry (ESI-MS), including lowering voltages on detector or capillary, increasing cone gas flow rates, or adjusting the probe position. A combination of strategies generally allows researchers to make the best possible compromises when studying reactive compounds at relatively high concentration.