In Situ Monitoring of Marine Environment by Multi-Analyte Microfluidic Platform

A low-cost, compact sensor platform for monitoring seawater conditions will greatly benefit environmental studies by providing critical information to understand how nutrients and pH levels correlate to fish kills and aquaculture issues. Here, we demonstrate a multi-analyte microfluidic device fabricated through stencil patterning and lamination of plastic film stacks. This design offers the advantages of time-saving fabrication and integration of dissimilar materials in three-dimensional structures for detection of different analytes. The microfluidic structure incorporates electrochemical desalination and potentiometric sensing units for tracking salinity, nitrate concentration, and pH concentration. The background of high sodium chloride concentration in seawater is mitigated by the desalination unit to improve detection limits. We will show the sensor platform operating in relevant ocean conditions, for example salinity in the range of 10-40 PSU, pH between 6 to 9 and nitrate concentration in the range of 10^-4 M- 10^-2M, to enable in-situ monitoring of the marine environment.