Provided herein is technology relating to detecting gaseous analytes and particularly, but not exclusively, to devices and methods related to detecting gaseous analytes by monitoring changes in liquid crystals upon exposure to the gaseous analytes.

Amount of combined nitric oxide or nitric oxide presented as iron nitrosyls in a blood sample is determined by directing a low power electromagnetic radiation beam at a blood sample to liberate nitric oxide gas, dissolving the liberated nitric oxide gas and electrochemically detecting amount of dissolved nitric oxide gas.