| Light stabilizers can effectively slow down or inhibit ultraviolet photooxidation,thereby improving the durability of polymer materials.They have become an important additive in food contact materials.However,light stabilizers have certain harmfulness to the biological environment and human health.Relevant regulations and standards have been issued at home and abroad to limit the use of light stabilizers in food contact materials.In GB 9685-2008?Hygienic standards for uses of additives in food containers and packaging materials?,China stipulated the maximum usage and specific migration or maximum residue of some light stabilizers in food packaging materials,but did not formulate corresponding detection standards.Therefore,this paper studies 19 kinds of light stabilizers commonly used in the market and establishes the analytical methods of these substances in food contact materials.The results of this study are of great significance for the state to speed up the formulation of standard detection methods of light stabilizers in food contact materials and to ensure food safety.The main research contents and conclusions are as follows:(1)The best pretreatment conditions were obtained by optimizing the pretreatment conditions.A method for the determination of 19 light stabilizers in food contact materials by high performance liquid chromatography was established.The extraction efficiency of eight extractants,tetrahydrofuran,n-hexane,ethyl acetate and ethanol,was studied.The optimum extractant was tetrahydrofuran/n-hexane=50/50(V/V).The effects of extraction time and extraction times were investigated.The experimental results showed that extraction time of 1 h and extraction times of 1 time were the best conditions.The quantitative lim it of the established analytical method is 5-25 mg/kg.The linear correlation coefficient of each substance is above 0.9995.The recovery rate of the method is between 87.76%and 98.69%,and the relative standard deviation is less than 5%.The method can meet the requirements of actual detection and analysis.(2)Based on the establishment of a high performance liquid chromatography method for simultaneous determination of 19 light stabilizers,the migration of positive samples of inks on the surface of plastic packaging bags soaked in water,acid,alcohol and isooctane simulators at 40? for 10 days was determined.The migration of positive samples of inks on the surface of paper products soaked in water,acid,alcohol and isooctane simulators at 80? for 6 hours was also determined.The migration law was studied.The experim.ental results show that the light stabilizers in th e surface printing ink of plastic packaging bags and paper products migrate less in water and low concentration ethanol.When the ethanol concentration increases,the migration also increases.The light stabilizers of benzotriazoles migrate more in non-polar isooctane simulators.It was found that the amount of migration was related to the material of plastic packaging bags.The presence of white cardboard and polyethylene film prevented the food simulator from contacting with the surface ink,and to some extent prevented the light stabilizer from migrating to the food simulator.(3)Analysis of the results of more than 100 actual samples.The results showed that only a few samples of food contact materials sold or imported or exported in Xiamen were detected as light stabilizers.Most of the food contact materials were low in light stabilizers.Within the permissible range,the positive samples were relatively safe.Tracing back to the positive samples,it was found that all the positive samples belonged to three non-products,and none of the large-brand samples were detected. |
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