微塑料与重金属复合胁迫对谷胱甘肽抗氧化活性的影响及机理分析OA

To investigate the combined effects of microplastics and heavy metals on the antioxidant function of glutathione(GSH),a simplified in vitro free radical scavenging model was established using GSH and 1,1-diphenyl-2-picrylhydrazyl(DPPH)radical.The influences of polyethylene terephthalate(PET),polystyrene(PS),and polypropylene(PP)coexisting with varying concentrations of As(Ⅲ),As(Ⅴ),Cd2+,and Pb2+on the DPPH radical scavenging efficiency of GSH were studied.Dynamic changes in the relative contents of GSH and oxidized glutathione(GSSG)in the arsenic-containing systems were monitored by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry(HPLC-ESI-MS).The results demonstrated that the promoting effects of As(Ⅴ),Pb2+and Cd2+on DPPH scavenging activity of GSH decreased progressively as their relative concentrations decreased,whereas the effect of As(Ⅲ)exhibited an initial increase followed by a subsequent decline.Under a high microplastic content condition(Ratio of reaction solution to microplasticsmLiquid:mMPs=1:2),the aged microplastics consistently enhanced the free radical scavenging rate.In the closed reaction system,a certain molar ratio of GSH/As(Ⅲ)within the range of 1:2 to 2:1 was most favorable for the generation of GS·or GSSG,thereby accelerating the radical scavenging reaction rate.The reduction and complexation reactions of As(Ⅴ)competitively consumed GSH in the DPPH radical scavenging process,resulting in a negative correlation between GSSG generation and As(Ⅴ)concentration,as well as a lagged change in GSH content.