Ion counting and ion intensity measurements in time‐of‐flight mass spectrometry. Application to matrix‐assisted laser desorption

A time‐to‐digital converter coupled to a charge‐to‐digitalconverter has been used to record mass spectra in matrix‐assisted laser desorption(MALD) time‐of‐flight mass spectrometry. Masses above 100 000 Da have been detected by ion counting. Utilizing an electrostatic mirror, good mass resolution has been achieved in MALD. When the number of detedted secondary ions is small the sensitivity of mass measurements is improved by using a charge‐to‐digital converter rather than a transient recorder.