Abstract: A detector for, and a method of, detecting analytes in gases in described. The detector comprises a sorbent for sorbing therein and/or thereon and/or desorbing therefrom, an analyte included in a gas exposed thereto, at a zeroth temperature, pressure (T0,P0), a controller arranged to change the zeroth temperature, pressure (T0,P0) to a first temperature, pressure (T1,P1) according to a first equation, to desorb and/or sorb at least some of the analyte; and a sensor arranged to sense at least some of the analyte and to output a response corresponding to the sensed analyte. The response comprises and/or is a characteristic response of the analyte. The first response is modified based on a first baseline response at the zeroth temperature, pressure (T0,P0).

Abstract: We describe a method of selectively detecting the presence of an analyte, the method comprising: providing at least one waveguide, the waveguide having a core comprising porous material; absorbing an analyte sample into said porous material of said core such that said analyte sample is held within pores of said core; waveguiding radiation along said at least one waveguide to an output to provide output radiation; measuring one or more spectral features of said output radiation due to absorption or scattering of said waveguided radiation by said absorbed analyte sample; selectively identifying the presence of a target analyte in said analyte sample from said one or more spectral features. In embodiments spectral features are measured for multiple different waveguide core regions having different physical/chemical properties modified to provide additional selectivity to the target analyte(s), and these measurements combined to identify the target analyte.