Patent ID: 8668870

Claim:
A detection apparatus comprising: a reaction region; and an analysis region where ion species produced in the reaction region are detected; and a gas flow system that is selectively operable to supply a flow of clean gas through the reaction region; an apparatus that is selectively operable to momentarily admit an analyte gas or vapor to the reaction region; a processor unit operatively connected to operate the gas flow system and the apparatus for momentarily admitting the analyte gas or vapor; wherein the processor unit is arranged and configured to operate the gas flow system and the apparatus for momentarily admitting the analyte gas or vapor to reduce the flow of clean gas through the reaction region substantially to zero just prior to momentarily admitting the analyte gas or vapor to the reaction region such that the residence time of the analyte gas or vapor in the reaction region is increased; and wherein the processor unit is also arranged and configured to operate the gas flow system to subsequently increase the flow of clean gas through the reaction region.