Determining curtain plate integrity in differential mobility spectrometry

Abstract

A DMS device receives a curtain gas that includes a chemical modifier into its curtain plate. Before or while receiving ions of an analyte, the DMS device steps the CoV through a series of values in order to apply different CoV values to at least one precursor ion derived from the chemical modifier. For each CoV value of the series of values, a mass spectrometer selects and mass analyzes the at least one precursor ion. An intensity is produced for each CoV value of the series of values. An intensity versus CoV value peak is calculated from the intensities measured. A representative CoV value is calculated for the peak. The difference between the representative CoV value and known CoV values that represent an uncontaminated curtain plate is calculated. If the difference is greater than or equal to a predetermined threshold value, the curtain plate is determined to be contaminated.