(372e) Real-Time Underwater Detection of Trace Organic Analytes

Underwater detection of trace analytes requires a sensor system with superb sensitivity because of the low solubility of most organic compounds in water. Furthermore, analytes rapidly mix in the water, and prevailing currents make the concentration highly localized and non-uniform. In addition, chemical and biological interferents in the seawater can introduce bias and complicate analysis. To address this, a microfluidic, surfaced enhanced Raman scattering (SERS) device was developed to detect analytes of interest at low part per billion (ppb) concentrations in seawater. The multi-analyte sensor is compact, low-power, and ruggedize for a marine environment aboard an autonomous underwater vehicle (AUV). Lab-scale demonstrations were conducted to validate instrument performance and determine practical limits of detection in a seawater matrix. Sensor development, analytes tested, and operating parameters (e.g., limits of detection, response time) will be presented.