Detection of vapor phase compounds by changes in physical properties of a liquid crystal

A method of detecting an analyte in a gaseous phase comprising:

• a) providing a liquid crystal assay device comprising at least one surface in contact with a liquid crystal composition, wherein said liquid crystal composition comprises a mesogen selected from the group consisting of MBBA, EBBA, E7, MLC-6812, MLC 12200, 5CB (4-n-pentyl-4′-cyanobiphenyl), 8CB (4-cyano-4′octylbiphenyl) and 4-(trans-4-heptylcyclohexyl)-aniline and wherein said surface is not modified with a self-assembled monolayer;
• b) exposing said liquid crystal assay device to a sample suspected of containing an analyte;
• and
• c) interrogating said liquid crystal assay device to detect said analyte, wherein the presence of said analyte is indicated by a change in the properties of said liquid crystal, wherein said analyte is selected from the group consisting of hydrogen sulfide, nitrogen dioxide, and sulfur dioxide.