| The topic detected harmful substances in the flexible packaging and printing ink,determined the two representative harmful solvents,studied on the residual in the flexible packaging and migration into food stimulants of the solvents.The hazardous substances in flexible packaging and printing inks were extracted and analyzed by solid phase micro extraction-gas chromatography mass spectrometry (SPME-GC-MS).The main components are complex,including carbon oxides, esters, alcohols, ketones, amides, aromatic hydrocarbons,the relative content of ester solvent in ink printing is98.6%,finally the xylene and ethyl acetate were used as subjects.The migration of organic solvent in packaging materials depends on the partition coefficientDetermined partition coefficient Ks/p of the organic solvent between the polymer and food simulants by changing the ratio of gas and liquid in a closed system.The results showed that Ks/p of xylene were0.090-0.157, Ks/p of ethyl acetate was0.121～0.169.Higher partition coefficient indicate that it is easy to migrate.Ks/p has a relationship with organic solvent itself,the nature and concentration of food stimulants and the physical and chemical structure of the polymer.The residual of xylene and ethyl acetate in PET/PE and PP/PE flexible packagings through GC qualitative and quantitative techniques.The results showed that the content of organic solvent in flexible packagings decreased with time,finally tended to equilibrium. The initial concentration of PET/PE and PP/PE flexible packaging treated with high concentrations of xylene were2.37mg/m2and10.25mg/m2,the migration of equilibrium was0.180mg/m2and0.394mg/m2;The initial concentration of ethyl acetate was2.79mg/m2and3.42mg/m2,the migration of steady was0.378mg/m2and0.768mg/m2. The amount of residual organic solvents in PP/PE is more than PET/PE,the main factor are the size of the organic solvent and solubility parameter.The rule of organic solvent residued in flexible packaging conforms with the Boltzmann equation.Studied on the migration of xylene and ethyl acetate into four foods stimulants,including3%,6%acetic acid,10%,40%ethanol.The results showed that the migration reached equilibrium with time.The amount of xylene migrating into acetic acid was0.3-0.41mg/L and ethanol was0.308-0.595mg/L;The amount of ethyl acetate migrating into acetic acid and ethanol was0.234～0.59mg/L,0.529-0.681mg/L respectively.The smaller molecular weight of organic solvent,the easier to migrate; The greater initial concentration of the organic solvent in flexible packaging,the more migration;High concentrations of liquid food simulants will accelerate the migration, the order of migration in stimulants.ethanol> acetic acid.The experimental datas was analyzed with SPSS to set up the appropriate curve model.The migration of xylene and ethyl acetate into3%and6%acetic acid are accord with the cubic curve model:y=bo+b1x+b2x2+b3x3,the migration into10%and40%ethanol conform to the quadratic curve model:y=ao+a,x+a2x2.R square which is up to0.9can response good fitness.10kinds of representative flexible packagings and contents were selected to be detected and analyzed. The results show that the flexible packagings and food are detected with acetone,toluene,xylene, dibutyl phthalate (DBP),which was used in the printing ink solvent,ethyl acetate was not detected; The DBP is detected in90%food samples,ranging from4.26to10.21ug/L,the toluene is detected from sample1to sample5,the concentration of1.76～4.52ug/L, the xylene is3.75ug/L in sample9, individual substance does not exceed the national limit. |
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