The Safely Evaluation And Migration Study About The Residue Of Heavy Metal In Food Packing Materials

This paper takes food packaging materials as the research object. The contents of7kinds of heavy metals in30kinds of paper food packing materials and131kinds of plastic food packing materials were analyzed.The digestion methods for paper/plastic food packing materials such as electric-heating-plate digestion method and high-pressure-tank digestion method were studied. Electric-heating-bord digestion method was easy operation, small dosage of acid and high accuracy. However, the accuracy of the content of some elements were not high. High-pressure-tank digestion method was safe, less pollution, but it needed the step of driving off acid, thus, increased the time of digestion. In order to solve the problem of frequent liquid flooding for the digestion of some plastic food packing materials, the sealed high pressure resolution method was used. The dosage of concentrated nitric acid, perchloric and hydrogen peroxide was optimized. The results showed that the optimum dosage was5ml,3ml,2ml, respectively. The best digestion temperature and time was180℃and8h.The detection method of copper in packaging materials was flame atomic absorption spectrophotometry while lead, cadmium, chromium and aluminum was detected by graphite furnace atomic absorption spectrophotometry. The atomic fluorescence spectromtry was used to determine arsenic and mercury.30kinds of paper food packaging materials and131kinds of plastic food packaging materials were selected from a large supermarket. All of them contacted with food directly. The contents of heavy metals in food packaging materials were not harmful to customer’s health, even if all of the heavy meatals moved into food.4%acetic acid, deionized water, cooking oil and30%ethanol were used to simulate the acidic foods, neutral foods, fatty foods and alcoholic foods.