Determination of chemical warfare agents by low cost differential mobility spectrometry

A low-cost differential mobility spectrometer (DMS) was constructed using polytetrafluoroethylene printed circuit boards with two pairs of gold electrodes. The printed circuit boards were used to construct the drift tube into which the gas samples are introduced by a carrier gas and ionized. The ionized gas moves toward the gold electrode to which an asymmetric voltage is applied. Only the ionized gas with the proper ion mobility leaves the electrode region and reach the detection electrodes to form the ion current. Traces of five chemical warfare agents, including dimethyl methylphosphonate, triethylamine, 2-diisopropylaminoethanol, diethylaminoethanol, and N, N-dimethylethanolamine, were prepared using the permeation tube method and introduced into the sensor. All of the chemicals show characteristic ion peak shifts in the electric field. The limits of detection for the analytes are less than 1 ng/L. The recovery time was less than 10 s and the response time is 2 s. The developed sensor exhibits the ability to detect and distinguish between these chemical warfare agents.