Abstract:

Proteins could be cross-linked in the presence of reactive oxygen species. Since hydroxyl radical is the most oxidative reactive oxygen species, the hydroxyl radical formation rates from hydrogen peroxide (H2O2) were measured during irradiation in artificial seawater.

Suggested Citation:

Luni Sun, Peter Santschi. 2020. Hydroxyl radical formation rates during irradiation of hydrogen peroxide in artificial seawater. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/n7-js8z-gm69

Publications:

Sun, L., Xu, C., Lin, P., Quigg, A., Chin, W.-C., & Santschi, P. H. (2021). Photo-oxidation of proteins facilitates the preservation of high molecular weight dissolved organic nitrogen in the ocean. Marine Chemistry, 229, 103907. doi:10.1016/j.marchem.2020.103907

Purpose:

To measure hydroxyl radical formation rates during irradiation of H2O2 in artificial seawater.

Data Parameters and Units:

Sample [dark1-3, light1-3]; Hydroxyl radical formation rate (µM/h). Please note dark = dark control, and light = irradiated sample.

Methods:

Hydrogen peroxide (H2O2) was added into artificial seawater to a final concentration of 300 mg/L as the hydroxyl radical (∙OH) source. The probe benzene was added to a final concentration of 10 mM. Benzene can react with ∙OH to form phenol. The samples were irradiated by Suntest system. The samples wrapped with aluminum foil were used as dark controls. As the fraction of phenol formed within all photoproducts is constant, i.e. 69%, thus enabling the use of phenol concentration to calculate the ∙OH formation. After irradiation, the phenol concentration was measured by high-performance liquid chromatography (HPLC) with fluorescence detection (Waters). The excitation/emission wavelengths were 260/310 nm. The ∙OH formation rate was estimated by the phenol formation rate (Sun et al., 2014).

Instruments:

High-Performance Liquid Chromatography (HPLC).

Error Analysis:

Errors were a standard deviation from triplets.

Provenance and Historical References:

Sun, L., Chen, H., Abdulla, H. A., & Mopper, K. (2014). Estimating hydroxyl radical photochemical formation rates in natural waters during long-term laboratory irradiation experiments. Environ. Sci.: Processes Impacts, 16(4), 757–763. doi:10.1039/c3em00587a

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