A laser flash photolysis study of nitrous acid in the aqueous phase

The OH quantum yield from the photolysis of nitrous acid in the aqueous phase by the 355 nm light was measured to be 0.25 ± 0.03. OH radical thus formed reacted readily with HNO2 to produce NO2, which sequentially reacted with HNO2 to form the HNO2–NO2 adduct. The NO2 + HNO2 reaction was reversible with a forward rate constant of 3.76 × 107 dm3 mol−1 s−1 and a backward rate constant of 1.06 × 105 s−1. Decay of the HNO2–NO2 adduct would most likely generate HNO3 and NO at a rate constant of 3.0 × 103 s−1

Reactions between the SO4 center dot- radical and some common anions in atmospheric aqueous droplets

The rate constants of reactions between the SO4.- radical and some common anions in atmospheric aqueous droplets e.g. Cl-, NO3-, HSO3- and HCO3- were determined using the laser flash photolysis technique. Absorption spectra of SO4- and the product radicals were also reported. The chloride ion was evaluated among all the anions to be the most efficient scavenger of SO4.-

Polymer characteristics of catechin and catechin-Ge4+ measured with a technology of mass spectrometry

The catachin mainly consists of (-)-epigallocatechin (EGC), (-)-epicate-chin (EC),(-) epigallocatechin-3-gallate (EGCG), and (-)-epicatechin-3-gallate (ECG). Using a combined method of high performance liquid chromatography-electrospray ionization-Q-time of flight (HPLC-ESI-Q-TOF) mass spectrometry (MS), polymer compounds of EGCG in the catachin can be separated and analyed the same results were further approved by matrix assisted laser desorption ionization (MALDI)-TOF MS. The EGCG-Ge4+ compounds synthesized by normal organic synthesis were further purified by a rapid reversed phase-HPLC for studying inhibition growth rate of the lung cancer cells. During the analytical process of EGCG-Ge4+ molecular structures with infrared spectrometry and MALDI-TOF MS, it was found that EGCG not only had polymer characteristics, but also bound to the metal Ge4+ (or other heavy metal ions, M2+) for forming EGCG-Ge4+ (or EGCG-M2+) and its polymers. The experimental results showed that both EGCG and EGCG-Ge4+ could inhibit the growth rate of lung cancer cells, showing the similar rate within the 24 h for cell incubating. However, this inhibition rate with EGCG-Ge4+ was much higher than that of EGCG, approximately enhancing 30% similar to 40% rate for inhibiting growth of lung cancer cells was observed within the incubating time covering from 24 to 72 h. Even so, both compounds cannot inhibit the growth rate of melanoma cells. It suggest that the compound EGCG-Ge4+ has potentials for developing new drugs for curing lung cancer