Study On Removal And Detection Of Heavy Metal Contaminants In Polysaccharide Extracted From Abalone Visceral

Abalone viscera takes about 1/3 of its total weight,and it is rich in bioactive polysaccharide which is potential to be developed into health care products,which attracts many studies fucous on in recent years.However,due to the presence of various natural sources and cumulative response of heavy metals,there must be a lot of heavy metals in abalone viscera,which are accumulated by eating much algae and other food chain.Therefore,how to detect heavy metals in abalone viscera polysaccharide and figure out their distribution has been premise to develop abalone viscera polysaccharides(AVP)into a health care product.In this paper,the method of ICP-MS was used to detect heavy metals in each polysaccharide samples during removing heavy metals from AVP.And the changes in the content of heavy metals(Cr,Ni,Cd,Pb,As)was also studied.In order to chose the best method to remove heavy metal Hg,secondary alcohol precipitation,dialysis,activated carbon adsorption,high adsorption activated clay were individually applied.1 The method of ICP-MS was established to detect Cd,Pb,As,Cr,Ni of AVP.The results indicated that nitric acid was the best digestion and only 5mL was used;the digestion condition was digesting 20min under 190 C.2 Through the optimization of the device,the best condition were found when detecting under the mode of He:carrier flow is 0.98mL/min,auxiliary flow is 0.12mL/min,the flow rate of helium is5.0mL/min.3 The results of recovery and precision measurement demonstrated that the rate of recovery was ranged between 90%to 110%,the relative standard deviation(RSD)was changed between 1%to 10%,which basically accord with the national standard.4 Uncertainty in measurement for the method of ICP-MS was analyzed,the results showed that the established method was credible and effective.5 Polysaccharide,protein and heavy metals were detected during investigating the processing of extracting AVP.The following results were found:(1)it is viable for new established method of ICP-MS to detect heavy metals in digestive fluid polysaccharide and AVP.(2)Before extracting AVP,abalone viscera should be pretreated by removing substance in alimentary canal because 22%of plant polysaccharide and a certain amount of heavy metals.(3)the content of heavy metals was decreasing during extracting AVP,and the content of heavy metals in final AVP sample accord to the limits in standard 16740-1997.(4)Mechanical centrifugation played a role on removing some kinds of heavy metals.Most of heavy metals were conjectured to exist in the states of free or combination with protein.(5)resin has an significant effect on decoloring.(6)resins are selective,which have strong adsorption of heavy metals.6 Secondary alcohol precipitation,dialysis,activated carbon adsorption,high activated clay were respectively to remove Hg in AVP which was obtained after alcohol precipitation.The results indicated high activated clay could effectively remove heavy metals and increased the content of AVP.