The Speciation Analysis Of Hg And Pb Based On CE-ICP-MS Together With On-line Pre-concentration And The Characterization Of Lead In Seafoods Collected From Fujian Coast

Studying on the speciation analysis of toxic elments in the environment and food is of great significance to assessing food security and environmental safety,because the chemical form of an element affects its bioavailability and toxicity directly.The main aim of this paper is to develop the methods for the speciation analysis of mercury and lead by using CE-ICP-MS together with on-line concentration,and further to investigate the speciation characteristics of lead in seafoods collected from FuJian coast.The main contents included:(1)A novel method for the ultra-sensitive detection of Hg2+,methyl mercury(MeHg)and ethyl mercury(EtHg)based on CE-ICP-MS together with field-amplified on-line preconcentration technique has been developed.The proposed method has obvious analytical advantages,such as high sensitivity and excellent stability etc.Under the optimal conditions,it can be used to detect MeHg,EtHg and Hg2+ within 30 min with the detection limits of 0.001,0.011 and 0.007 ngHg/mL,respectively.In comparison with the normal CE-ICP-MS method,the sensitivity of the proposed method has been increased by 100 times,i.e.the detection limit was decreased by 100 times.With the help of the proposed method,we have successfully determined the different species of mercury compounds in tap water with a RSD<5%(n=6)and a recovery of 92-109%without any preconcentration.(2)A CE-ICP-MS method for the speciation analysis of lead and a micro-wave assisted method used to extract trace lead compounds from seafood samples was developed.The micro-wave assisted extraction method is simple and environment-friendly,it can be used to effectively extract trace lead from seafood samples without altering their species.The CE-ICP-MS method has high sensitiveity,it can be used to detect Pb2+,TML and TEL with a detection limit of 0.012-0.084 ngPb/mL and a RSD<5%(n=5).By using the analytical method and extraction method developed above,we have successfully detected different species of lead compounds in seafoods collected from Fujian coast in detail with a recovery of 91-103%.Our results showed that the speciation of lead in the seafoods have no obvious correlation with sampling areas,it seem depend on the species of seafoods.All Pb2+,TML and TEL were detected in some seafoods,whereas only the Pb2+ was detected in another seafoods.In comparison with shellfish and shrimp,the fish has higher concentration of total Pb and organic Pb with a average concentration of 2.414 and 1.736 μgPb/g dried weight rescpectively,whereas the average concentration of total Pb and organic Pb in shellfish and shrimp is 1.433 and 0.651 μgPb/g dried weight rescpectively.However,the percentage of organic Pb in the total Pb is similar for all fish,shellfish and shrimp.Our results indicated that lead content in seafoods seems to be related with the nutrition level of food chain.