Study On The Detection And Migration Of Antioxidants In Rubber Gaskets For Food Contact

The migration of harmful substances in food contact materials is one of the main causes of food safety problems.Rubber sealing gaskets are often used in food processing machinery in the working parts of the pipeline and storage containers.Antioxidants are commonly used as additives in rubber gaskets for food contact.There are national standards to limit their usage and migration.However,at present,there is no detection method standard for antioxidants in rubber materials for food contact at home and abroad,and the detection and monitoring of antioxidants residues and migration are still imperfect.Therefore,it is of great engineering significance to establish the detection method of antioxidant residue and migration in rubber materials and to study the migration behavior of antioxidants in rubber materials.The research object of this subject is the rubber sealing gasket used for food contact.The method for the determination of antioxidants residues in rubber gaskets for food contact and the method for the determination of antioxidants migration in food simulants were established by microwave extraction and triple quadrupole liquid mass spectrometry.Methodological evaluation was conducted for the two methods created.The migration tests of EPDM and NBR positive samples were carried out at different temperatures,boiling water cooking,microwave and high-pressure sterilization processing conditions.And the migration laws of antioxidants to food simulants were studied.Based on Fick’s second law and experimental data,the diffusion coefficient and migration model characterization of antioxidant were obtained.The influence factors of diffusion coefficient and the relationship between temperature and diffusion coefficient were discussed.The pre-exponential factor and activation energy of antioxidant parameters in EPDM and NBR were obtained by the Arrhenius formula.The main research contents and results are as follows:(1)By optimizing the chromatographic column,elution procedure,mass spectrometric conditions and pretreatment methods,the microwave extraction-triple quadrupole liquid-mass spectrometry method was established for the determination of 9 antioxidants residues in the rubber gasket for food contact.The detection limit,recovery and precision were used as evaluation indexes to carry out methodological evaluation.The recovery rate of antioxidants was 25.0～101.0%,the instrument detection limit was 0.003～0.083 μg/L,the instrument quantitative limit was 0.01～0.25 μg/L,the method detection limit and method quantitative limit were 0.005～0.160 mg/kg and 0.02～0.50 mg/kg,respectively.The linear range of 9 antioxidants was 0.01～0.5 mg/L,and the correlation coefficients were above 0.99.The recoveries and relative standard deviations were 73.1～119.8% and 0.7～9.3%,respectively.The method has good accuracy and reproducibility.(2)A detection method of 6 antioxidant migration in 4 kinds of food simulants were established.The detection limit,limit of quantitation,recovery and precision were used as evaluation indexes to carry out methodological evaluation.The detection limit of the method and the limit of quantification were 0.0003 mg/L and 0.001 mg/L,respectively.In the range of0.005～0.1 mg/L,the linearity of the 6 antioxidants was good,and the correlation coefficients were above 0.99.The recoveries in 10% ethanol,4% acetic acid,20% ethanol and 50% ethanol were 86～114%,and the relative standard deviations were 0.3～11.1%,which could meet the standard requirements.(3)The EPDM and NBR positive samples were used to carry out the migration test at the conditions of different temperatures,boiling water cooking,microwave and autoclave.The migration laws of antioxidants to food simulants were studied.Then,the migration tests were carried out at 100 ℃ for 48 h and 40 ℃ for 6 d by using rubber gaskets for contact with commercial food.The evaluation results showed that the migration risk of antioxidants in the commercial samples was low.(4)Based on Fick’s second law and experimental data,the diffusion coefficient and migration model characterization of antioxidants were obtained.The influence factors of diffusion coefficient and the relationship between temperature and diffusion coefficient were discussed.The parameters pre-exponential factor and activation energy of antioxidants in EPDM and NBR were obtained by Arrhenius formula.