Detection of Oxidation of L-Cysteine by Dimethyl Sulfoxide in Aqueous Solutions by IR Spectroscopy
We have used IR spectroscopy to study the reaction between L-cysteine and dimethyl sulfoxide in aqueous medium. We have found that reaction occurs with formation of an insoluble product, which we have identified. We show that oxidation of L-cysteine by dimethyl sulfoxide can occur at an appreciable rate under mild conditions, with formation of L-cystine, dimethyl sulfide, and water.
Abstract The temperature-spectral dependencies of refractive indices ni and birefringence Δni of first time synthesized RbNH4SO4 crystals in wide temperature (77–300 K) and spectral (250–850 nm) regions were measured. It was shown that ni dispersion is normal and very fine described by Zelmeer's formula. It was found that Δny = 0 for λ = 633 nm at T=189 K and the isotropic point have a nearly “isospectral” character. The isotropic point is displacing to longwave region at temperature decrease. The second-order phase transition at T = 120 K was observed.