Simultaneous Determination of Multiple Photochemically Produced Reactive Intermediates Under Solar Illumination

Area of Science:

• Environmental Chemistry
• Photochemistry
• Aquatic Chemistry

Background:

• Photochemically produced reactive intermediates (PPRIs) are vital in sunlit aquatic environments.
• Existing methods struggle to quantify carbonate radicals (CO₃•−) and long-lived oxidative organic radicals (LOORs).

Purpose of the Study:

• To develop a reliable method for simultaneous quantification of five key PPRIs in sunlit waters.
• To address the lack of accurate measurement techniques for CO₃•− and LOORs.

Main Methods:

• Development of a multiple-probe chemical method using two complementary probe sets.
• Utilizing high-level and low-level probe concentrations to differentiate and quantify PPRIs.
• Application of kinetic modeling to assess method accuracy and interferences.

Main Results:

• Successful simultaneous determination of HO•, ¹O₂, ³CDOM*, CO₃•−, and LOORs in simulated and natural waters.
• Demonstrated minimal interference from halogen radicals at typical freshwater bromide concentrations (<10 μM).
• Validated the method's applicability to various freshwater and wastewater samples.

Conclusions:

• The developed multiple-probe method offers a practical, sensitive, and accessible tool for comprehensive PPRI analysis.
• This advancement enables a better understanding of photochemical processes in aquatic systems.
• Facilitates accurate assessment of water quality and pollutant degradation pathways.