Gas-phase photocatalysis experiments may benefit from the high sensitivity and good time response in product detection offered by mu-reactors. We demonstrate this by carrying out CO oxidation and methanol oxidation over commercial TiO2 photocatalysts in our recently developed high-sensitivity reactors. We demonstrate that the system exhibits great versatility in terms of photocatalyst, illumination source and target reaction. (c) 2010 Elsevier B.V. All rights reserved.