The sensor was composed of 8 layers and contains the main holder (A) and microfluidic module (B) with immobilized protein – laccase. Microchannels for the analyte which are placed in the microfluidic module were cut with LTCC technology, as well as openings of the optical fibre. Microchannels which are connected to LED sensor are incorporated with chemosensitive enzymatic film. The general procedure for detection is based on application of Graphene Quantum Dots (GQD) and dopamine solution onto microchannels. Due to ability to self – polymerization, dopamine forms thick layer of film which is next adsorbed on the surface of Graphene Quantum Dots inducing Forster Resonance Energy Transfer and fluorescence quenching. The parameter is quite proportional to dopamine concentration.