|
|
|
| Feasibility investigation of quantitative analysis of dissolved inorganic carbon by Raman spectrometry |
|
|
|
|
Abstract The mean concentration of dissolved inorganic carbon(DIC) in seawater is about 2.05mmol/L. Approximately 93% of DIC is HCO3-, 6% is CO32-, and only 1% is CO2 and H2CO3. Since Raman activity of HCO3- is weak and the concentration of other species is low, it is impossible for DIC in seawater to generate Raman scattering that is intense enough to be detected. There is no report on quantitative analysis of DIC in seawater using Laser Raman Spectrometry so far. In order to break through the limitation, a Raman spectroscopy quantitative analysis method assisted with sample alkalization was proposed. HCO3- was treated as study object because it takes the largest share and the Raman activity of it was the weakest among all DIC species. The solution was alkalized to convert HCO3- into CO32- which was more Raman active. OH bending band of water was treated as the internal standard for its stability. The Raman spectroscopy analysis detecting limit of HCO3- was increased, and the quantitative analysis result showed good accuracy (relative error<6.5%).
|
|
Received: 11 December 2013
|
|
|
|
|
|
|
