An integrated, disposable, 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 relatively 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 a polymer substrate which contained injection moulded grating coupler. These devices have been designed to increase the interaction of the evanescent field light at the channel wall and with the sample in the channel. The DCLW device has been used to detect changes in the refractive index of different percentages of glycerol solutions and to detect low concentrations down to 10(-12) M fluorescein using a grating coupler.