An integrated, low-cost, dye clad leaky waveguide (DCLW) device has been fabricated and tested for both refractive index and fluorescence detection in mu-TAS applications. The chip comprises the required flow geometry and optical coupling elements in a robust device that is simple and inexpensive to fabricate. Disposable DCLW chips were fabricated at room temperature by spin-coating both the dye and silica sol-gel waveguiding layers on to a polymer substrate which contained an infected moulded grating coupler. These devices have been designed to increase interaction between the evanescent field light at the channel wall and the materials in the sensing layer within the channels. The DCLW device has been used to detect changes in the refractive index of different concentrations of glycerol and to detect low concentrations of fluorescien, down to 10(-12) M, using a grating coupler.