Development of a low-cost, high-sensitivity, and highly accurate sensor for dissolved CO2 measurements in natural waters based on the change in fluorescence of the pH sensitive indicator 8 - Hydroxypyrene - 1,3,6 - trisulfonic acid, trisodium salt (HPTS)

The topic of climate change garners much attention in society; however, most discussions on the subject refer only to global warming and its effects on sea levels, increases in tropical diseases, or increases in severe weather events. These mentioned effects are only one side of a multi-faceted phenomenon. Another equally important facet is the effect it can have on the oceans. At current atmospheric CO2 levels, it is thought that the oceans absorb approximately 40% of the fossil fuel related CO2 emissions. According to several models, we are poised to change the ocean's pH more in the next 300 years than in the last 300 million years. Although there are several devices and technologies that can monitor dissolved oceanic CO2, there are none that are small or affordable enough to deploy in appropriate numbers to adequately monitor the earth's oceans. This fact coupled with the lack of sufficient oceanic data for dissolved CO2 mandates another sensor's development -- ours. Our sensor is based on the change in fluorescence of the pH sensitive indicator 8 - Hydroxypyrene - 1,3,6 - trisulfonic acid, trisodium salt (HPTS) in solution due to the diffusion of dissolved CO 2 across a gas permeable Teflon AF membrane. Our device, which in controlled settings has approached the +/- 2 ppm limit required by the Large-Scale CO2 Observing Plan: In Situ Oceans and Atmosphere mandate, was kept affordable and small by employing emerging fabrication technologies in microfluidics and our partnership with Fluorometrix (Stowe, MA) , a leader in uFluorometer technologies.