SENSOR

This invention relates to a sensor for detecting an analyte in the presence of at least one interferent in a fluid sample. The sensor comprises a substrate, a channel disposed on the substrate, at least one transducer disposed in the channel, and a filter for selectively absorbing the analyte in preference to the at least one interferent. The filter is arranged in the channel remotely from the at least one transducer and the channel defines a flow path for the fluid sample such that the fluid sample contacts a first transducer to generate a first signal, followed by the filter, followed by the first transducer or a second transducer to generate a second signal.