Integration of an Emerging Highly Sensitive Optical CO2 Sensor for Ocean Monitoring on an Existing Data Acquisition System SeaKeeper 1000 (trademark)

• Main Author: Rao, Govind
• Other Authors: MARYLAND UNIV BALTIMORE COUNTY BALTIMORE MD DEPT OF CHEMICAL AND BIOCHEMICAL ENGINEERING
• Format: Text
• Language: English
• Published: 2012
• Subjects: Physical and Dynamic Oceanography; Optics; *OPTICAL DETECTORS; BASES(CHEMISTRY); CALIBRATION; CARBON DIOXIDE; DATA ACQUISITION; DYES; EMISSION; FLOW; FLUORESCENCE; LIGHT EMITTING DIODES; LIGHT SCATTERING; LOW COSTS; MASS; MONITORING; PROTOTYPES; PUMPS; OCEAN MONITORING; SEAKEEPER 1000TM DATA ACQUISITION SYSTEM; OCEAN ACIDIFICATION; FLOW CELLS; MASS EXCHANGERS; Ocean acidification
• Online Access: http://www.dtic.mil/docs/citations/ADA571554; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA571554

The novelly designed optical sensor for autonomous ocean monitoring works on equilibrium principles. When the pH-sensitive reagent solution sitting behind a gas-permeable membrane is exposed to seawater, the CO2 molecules present in the seawater diffuse across the membrane into the reagent and induce a pH change. After equilibrium is reached, the fluorescence is measured and the pCO2 data are recovered from a calibration curve. A specific feature of our measurement technique is the use of excitation ratiometric approach. A violet LED (Light Emitting Diode) and a blue LED are used to excite the sensing reagent through an excitation filter and the pCO2 dependent emission is measured through an emission filter by a photodiode.