Preparation Of Adsorption Material And The Application Of Determination Of Trace Lead, Cadmium In Salty Food

With a variety of food contamination issues have exposed frequently,people’s awareness of food safety was growing, the study of heavy metalsin food was also becoming increasingly important. Despite thehigh-resolution and high-sensitivity analytical instruments have beencontinuously developed and applied, the complexity of the sample or thelow content of the analyte was likely to cause the non-accurately results oreven can not get a result. Therefore, it is important to choose somematerials which not only can strongly absorb low levels of heavy but alsocan be used to separate and enrich heavy metals. In this paper, cotton andactivated carbon was used to synthesis three kinds of efficient absorbentmaterial, we got both the best adsorption conditions and desorptionconditions for lead and cadmium and selected the best adsorbent materialfrom the experiments. At the same time, we also explored the conditions ofinstrument of lead and cadmium, the results were as follows:(1) In order to adsorb lead, the best preparing method for cottoncellulose xanthate was that Cotton column was taken out and added into1%ethanol solution of sodium hydroxide, standing40min and drained,adding CS2and standing40min, washing the cotton to neutrality, filteringthe cotton and drying at50℃. The best preparing method for cottoncellulose xanthate to adsorb cadmium was roughly the same to lead, expect addition1%ethanol solution of sodium hydroxide to the cotton andstanding50min.(2) In order to adsorb lead and cadmium by using cotton cellulosexanthate, its best method was as follows.pH was4, adsorption time was15min and adsorption temperature was20℃, which were the bestadsorption conditions of lead. The concentration of eluent was3mol/LHCl, the volume of eluent was6ml, elution time was15min and elutiontemperature was40℃, which were the best desorption conditions of lead.pH was6, adsorption time was10min and adsorption temperature was30℃, which were the best adsorption conditions of cadmium. Theconcentration of eluent was4mol/L HCl, the volume of eluent was5ml,elution time was10min and elution temperature was50℃, which were thebest desorption conditions of cadmium.(3) Cotton cellulose xanthate had the best adsorption effect and thebest desorption effect to lead element and cadmium element, theadsorption rate of lead and cadmium was97.32%and95.06%, thedesorption rate of lead and cadmium was100.3%and95.75%(4)In the analysis of GF-AAS, the best matrix modifier of lead andcadmium was2%NH4H2PO4.The injection volume of lead was8μl, theinjection volume of cadmium was6μl. Ashing temperature was950℃andatomization temperature was1600℃, which was lead’s best instrumentworking conditions. Ashing temperature was600℃and atomization temperature was1500℃, which was cadmium’s best instrument workingconditions.(5) Detection the practical samples with cotton cellulose xanthateand the results showed that the method had a good separation andenrichment performance for lead and cadmium in salty food, the resultswere accurate, reliable and should be promoted.