Low-Cost Submersible Fluorometer for Fresh and Marine Water Environments

Abstract

Fluorescence technology is a powerful tool for the detection of harmful algal blooms, oil spill response, oceanographic tracer experiments, and much more. Two ways of fluorescence detection are presented here, a novel microfluidic inlaid approach and a classical approach. The lower limit of detection for the microfluidic approach was 47 nM (27 ppb) Rhodamine, whereas the submersible had 0.39 nM (0.22 ppb). The classical approach is a submersible which was simulated, implemented, temperature calibrated and deployed for field trials. The submersible uses a digital lock-in amplifier, and the housing is made from off-the-shelf components. When temperature calibrating the device the commercial Turner Cyclops 7 was calibrated along side it, yielding comparable results. The prototype and commercial sensors were mounted to an underwater remotely operated vehicle which was deployed in the Gulf of Saint Lawrence for tracer studies.