| abstract |
An ion mobility spectrometer has a drift chamber ( 1 ) with an inlet ( 2 ) at one end by which a gas or vapour being analysed is supplied to the chamber. After ionization, molecules are admitted through a gate 8 and flow along a drift region ( 9 ) to a collector plate ( 11 ). A drift gas is flowed through the drift region against the flow of ionized molecules and is circulated along a flow path ( 31, 32, 40 ) and ( 30 ), which includes a chamber ( 50 ) including a dopant. The dopant is 2,4 -pentanedione, which has been found to enhance the detection of a number of compounds especially toxic industrial chemicals and nitrogen compounds, such as those present in the breath of mammals. |