Effect of water vapor and formaldehyde detection with differential mobility spectrometry

Abstract

Differential mobility spectrometry (DMS) coupled with a mass spectrometer is used to demonstrate unambiguously the identification and quantification of the level-of-detection of formaldehyde. We show that impurities, which are inherently found in any formaldehyde standard, may lead to a miss-identification. Formaldehyde detection in the presence of two such impurities, methanol and methyl formate was found to be especially difficult due to significantly greater DMS sensitivity towards these compounds compared with formaldehyde. We also show that the intensity of species DMS signal and position of the reactant ion peak in compensation voltage space is strongly dependent on the prevailing water vapor level in the DMS.