Speciation Analysis And Transformation Of Arsenic In Seawater And Fish Samples In Tianjin Section Of Bohai Bay

As a toxic element,long-term and chronic exposure to arsenic will cause various kinds of health effects.In this thesis,the arsenic speciation in seawater and fish samples in Tianjin Section of Bohai Bay were investigated after the establishment of speciation analysis method for arsenic in biosamples.The migration and transformation rules were fluther illustrated based on the analysis of arsenic speciation in seawater and biosanples so as to provide relative theoretical foundation for the determination and standard formulation relevent to food safety.Main conclusions presented are surmarized as following:(1)AsB and AsC can not directly react with KBH4 to generate gas hydrides,and it is necessary to oxydative degradation at the function of K2S2O8 and UV irradiation before AFS determination.To increase the time of degradation reaction by lengthening the degradative pipeline will obviously enhance the analytical sensitivity.(2)Reversed phase ion pair chromatography,anion-exchange or cation-exchange chromatography only can not successfully separate As(?),As(V),MMA,DMA,AsB and AsC in DDW.However,they can be effectively separated by anion exchange and cation-exchange chromatographic columns in series and eluted by 3.0 mmol/L HCOONH4(pH=2.9).The resolutions were 3.3,2.4,2.9,16.8 and 3.3 in accordance with the order As(?),DMA,AsB,MMA,AsC and As(V)in the chromatogram.(3)During the pretreatment process of biosamples,it was found that the extraction efficiency for arsenic in biosamples by enzymolysis was obviously higher than solvent extraction method,and the purification of samples before extraction cann't enhance the enzymolysis efficiency.The recoveries and LOD for six kinds of arsenic species in spiked muscule samples of mullet were 67.74%-121.23%and 1.39?2.30 ?g/L with RSD no more than 7%.(4)Arsenic species in seawater of Bohai Bay(Tianjin Section)were analyzed,and the main presented form was As(V).Based on the comparison of arsenic content with the other areas,it was found that arsenic pollution in this studied area was relatively serious probably resulting from the reasons of anthropogenic discharge,geomorphology and hydrology.(5)Arsenic species in different organs of mullet in Bohai Bay(Tianjin Section)were analyzed,and the main presented form in muscule was nontoxic AsB,while the content of arsenic in liver was the highest and mainly existed in DMA.It was speculated that liver is the main place for the metabolic transformation of arsenic speciation in fish.