Abstract: Provided is an apparatus for the detection of volatile organic compounds (VOCs) for biological analysis, environmental testing and analytical testing. The gas detection apparatus includes: a channel having an inner surface and having at least one opening, such that the channel is optionally in fluid communication with a sample gas, the inner surface having a coating comprising: a first layer comprising a non-reactive metal or non-reactive metalloid compound; a second layer comprising a moisture barrier with high porosity; and a gas sensor disposed within the channel. Embodiments described herein provide low cost and highly selective gas detectors.