and real-time vibrational spectroscopic characterizations of the photodegradation of nitrite in the presence of methanediol.

Nitrite (NO) is one of the common salts in aqueous aerosols, and its photolytic products, nitric oxide (NO) and hydroxyl radical (OH), have potential for use in the oxidation of organic matter, such as dissolved formaldehyde, methanediol (CH(OH)), which is regarded as the precursor of atmospheric formic acid. In this work, the simulation of UVA irradiation in an aqueous mixture of NaNO/CH(OH) was carried out continuous exposure with a 365 nm LED lamp, and the reaction evolutions were probed by and real-time infrared and Raman spectroscopy, which provided multiplexity in the identification of the relevant species and the corresponding reaction evolution. Although performing infrared absorption measurements in aqueous solution seemed impracticable due to the strong interference of water, the multiplexity of the vibrational bands of parents and products in the non-interfered infrared regimes and the conjunction with Raman spectroscopy still make it possible to perform and real-time characterization of the photolytic reaction in the aqueous phase, supplementary to chromatographic approaches.