This work introduces a sensor for dairy antibiotic detection of ciprofloxacin in milk. We provide an important tool for antibiotic detection in milk and the main contributions of this work are as follows. We introduce a technique based on florescence spectroscopy and lock-in amplification for sensing ciprofloxacin in milk that is capable of detection below the regulatory limit. We compare the system against one without the integrated lock-in amplification, as in traditional fluorescence sensors. We provide microchip capillary electrophoresis results and place our work in context for future integration with microchip capillary electrophoresis.