FOTOLIZA DIRECTĂ A CISTEINEI ŞI TIOUREEI ÎN SOLUŢII APOASE

Angela LIS Universitatea de Stat din Moldova

Аннотация

DIRECT PHOTOLYSIS OF THE CYSTEINE AND THIOUREA IN AQUEOUS SOLUTIONS

It was studied direct photolysis in aqueous solutions of the thiourea and cysteine on the model system in order to estimate their role in the processes arising in the natural waters. It has been found that both of them, thiourea and cysteine, have been subjected to direct photolysis at irradiation with different artificial light sources. From the results obtained it was found that oxidation rate of these thiols depends directly proportional to the initial concentration of thiol in the system and the emission spectrum of the lamp. There were determined quantum yields of thiourea and cysteine using chemical actinometer K3[Fe(C2O4)3] · 3H2O. It was found that the quantum yield of thiourea is much greater than unity, which shows that on the destruction of thiourea only at the initial stage occurs photochemical reaction, which is followed by chemical reactions, possibly radical reactions, so thiourea can be the initiator of chemical self-purification reactions in the natural waters. Keywords: thiols, cysteine, thiourea, chemical actinometer, quantum yield, direct photolysis.