The Sample Pretreatment Method For Detecting Heavy Metal Of Protein Foods By ELISA

Enzyme-Linked Immunosorbent Assay (ELISA) was a kind of rapid and high effective method detecting heavy metals ions in water. Heavy metals exist in agricultural products as combinated state. In order to detect the content of heavy metal in foods, it was necessary to transformed combinated metals into free ions. Heavy metals content in agricultural products or aquatic products could be determined accurately by traditional detective methods, but the methods applied in field were impeded by time-consuming in pretreatment foods sample and the large equipment. It would be of a profound significance to develop a new method applied for fast and efficient sample pretreatment according to the request of ELISA detection.In the present, the perfect pretreatment conditions for aquatic products protein foods, such as oyster (Ostrea rivularis), mussel (Perna viridis) and Metapenaeus ensi, investigated with soak and extraction of three dilute acid (hydrochloric acid, sulfuric acid, nitric acid). The results show that the pretreatment conditions become perfect with 2M-4M concentration, 10min reaction time and 20-90℃temperature for HCl and 2M-4M concentration, 10min reaction time and 10-90℃temperature for H2SO4, and 2M-4M concentration,15min reaction time,10-90℃temperature for HNO3. The order of effection which dilute acid extract heavy metals (copper, lead, cadmium) of aquatic protein samples was HNO3> HC> H2SO4. The effection of methods extracted heavy metals (copper, lead, cadmium) of oyster with dilute nitric acid was the best in all the methods, which could replace the traditional pretreatment methods.The perfect pretreatment conditions for livestork and poultry protein foods, such as pork meat, beef meat, chichen meat and duck meat, investigated with soak and extraction of three dilute acid (hydrochloric acid, sulfuric acid, nitric acid). The results show that the pretreatment conditions become perfect with 1M-4M concen-tration, 10min reaction time and 10-90℃temperature for HCl and 1M-4M concentration, 10min reaction time and 10-90℃temperature for H2SO4, and 2M-4M concentration,15min reaction time,20-90℃temperature for HNO3. The order of effection which dilute acid extract heavy metals (copper, lead, cadmium) of aquatic protein samples was HNO3>HCl>H2SO4. The effection of methods extracted heavy metals (copper, lead, cadmium) of duck meat with dilute nitric acid was the best in all the methods, which could replace the traditional pretreatment method.Finally, heavy metal concentration of extractions of the aquatic products protein and livestock and poultry, obtained by the soak and extractive perfect conditions, was determined with ICP and ELISA,respectively. Statistical results show that there was a linear relationship between the two groups of concentration detected with the two methods. Therefore, the pretreatment methods of dilute acid extract could meet the requirements of detecting heavy metals (copper, lead, cadmium) of protein foods with ELISA.