Excited triplet states of dissolved organic matter (3DOM●) are critical transients in environmental photochemistry, and responsible for production of reactive oxygen species and pollutant attenuation. To characterize the energy transfer reactions of 3DOM●, chemical probes need to be developed. In the present study, sorbic alcohol and sorbic amine were employed as new chemical probes to investigate the triplet energy transfer pathway of 3DOM●, and compared with the result derived from sorbic acid as a probe. Unlike sorbic acid, no overlap was found between the solar spectrum and the absorption spectra of sorbic alcohol or sorbic amine, suggesting sorbic alcohol and sorbic amine are more suitable for the triplet state quantification under the solar irradiation. The steady-state triplet concentrations of SRNOM solution (4.0 mgCL-1) were calculated as 2.5 x 10−14 M under the simulated solar irradiation by using sorbic amine as the probe molecule, which was 3.8-folder higher than the measured value using the sorbic alcohol as a probe under identical conditions. Under the natural pH condition, sorbic amine, alcohol and acid present positive, neutral and negative charges, respectively, herein we suggested that the adsorption of these chemical probes on the negatively charged DOM would be significantly different due to the electrostatic forces. Therefore the positively charged sorbic amine, employed as a chemical probe, likely lead to the high measured quantum yield coefficients of 3DOM●. This study demonstrates that charge conditions in the probe molecules can play an important role in the triplet state capture capacity in aquatic photochemistry.

Development of the novel chemical probes for examining the triplet-excited state of organic matters

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.