| Paper is an ancient packaging material, as the protection awareness of people was enhanced, more attention was given to the plastic packaging material which caused the "white pollution", so the paper plastic packaging material might be gradually replaced by packaging materials. But during the pulping and papering process, a variety of chemicals including the basic chemical raw materials and some special chemicals were added, the main contents in which were a number of volatile organic compounds, which were potential contaminants in food packaging, and would cause a certain degree of hazards to human health and the environment. In addition, the paper used for packaging food usually contained kinds of trace elements, such as wax, fluorescent brighteners, sizing agents, organic chloride, plasticizers, aromatic carbohydrates, organic volatile compounds, curing agent, anti-oil, ammonia which could be extracted, fungicides and surfactants, and so on. These chemical residues might migrate into food. Therefore, a study in this area would have actual meaning to the daily lives of people.In this paper, the organic pollutants which might exist in three kinds of paper packaging materials were studied. The detection of GC-MS SIM method was set by quantitatively analyzing one of the DBP and Naphthalene. The migration of DBP and Naphthalene in the four simulations of liquid food was studied in this experiment to establish the migration model.By use of qualitative analysis for the three kinds of paper packaging materials, isopropyl benzene, toluene, benzene, formaldehyde, aniline, urethane, ethyl hexanol, naphthalene,1-methyl naphthalene, dibutyl phthalate, dibutyl maleate were detected in these paper packaging material. These organic pollutants were probably mainly come from fuel and paint or being as a plasticizer present in the paper packaging material.GC-MS SIM method was established:column:DB-5 (5% phenyl+95% methyl siloxane) fused silica capillary column. The column temperature program was programmed from initially 50℃2 min, then increased to 280℃at 10℃/min and held 5 min; injector temperature was 280℃.Carrier gas:high purity Helium (purity> 99.999%), flow rate of 1.1mL/min, splitless injection. Injection volume of liquid samples was 1μL. MS electron impact ionization source (EI); ion source temperature was 220℃; transmission line temperature was 280℃; ionization energy was 70eV; scan range:selected ion scan, solvent delay time of 7min; DBP of the characteristic ions was 104,149,150,205,223 and 149 for the quantitative characteristics of ions; characteristic ion of Naphthalene was 51,64,75,102,128 and 128 for the quantitative characteristics of ions.The contents of DBP and Naphthalene were very tiny in the paper packaging materials. DBP and Naphthalene were in good linearity in the range of 0.0500～50.0000μg/L. The limits of detection were respectively 0.2000μg/L and 0.4000μg/L.The recoveries of DBP and Naphthalene were separately 80.10% and 93.54%, and the relative standard deviations of DBP and Naphthalene were 2.9391% and 0.7410%.The initial DBP and Naphthalene concentrations in the treated paper by high concentration were determined in this assay, which were 127mg/L and 187mg/L. Influence of the migration time and temperature on the migrating amounts of DBP and Naphthalene in the four food simulated fluids was researched:With the extending of migration time, the migrating amounts of DBP and Naphthalene were increased, the migrating quantity in isooctane simulants were the most, followed by 15% ethanol and 3% acetic acid, whereas, in distilled water, the migrating amounts of DBP and Naphthalene were the least. The changes of DBP and Naphthalene contents in the four different food simulants were researched in this part. The results suggest that migration amounts would be raised with the temperature increasing, successively isooctane,15% ethanol,3% acetic acid, distilled water. The study on the time of reaching migration equilibrium of DBP and Naphthalene at different temperatures indicated that as the temperature rised, the time to reach equilibrium was shorten.Based on Fick's law, the mathematical migration model, of which the DBP and Naphthalene migrated into food stimulant liquid, was established: If the migration is very long, the equation can be simplified as: If the migration time is short, the equation can be simplified as:... |
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