顶空-气相色谱法分析PVC食品包装材料中氯乙烯、偏二氯乙烯、环氧氯丙烷的迁移量

Analysis of migration amount of vinyl chloride,vinylidene chloride and epichlorohydrin in PVC food packaging material by headspace-gas chromatography

建立PVC包装材料中氯乙烯、偏二氯乙烯、环氧氯丙烷在食品模拟物中迁移量的顶空-气相色谱检测方法。样品经N,N-二甲基乙酰胺提取,在80℃下顶空净化,采用极性色谱柱HP-INNOWAX对3种目标物进行分离,通过ECD检测器进行测定。氯乙烯、偏二氯乙烯、环氧氯丙烷的质量浓度在0.4~2.0mg/L范围内与色谱峰面积线性关系良好,相关系数均大于0.998,方法定量限为0.02mg/kg。空白样品加标回收率为80.5%~87.8%,测定结果的相对标准偏差为2.5%~5.6%(n=6)。氯乙烯、偏二氯乙烯、环氧氯丙烷在醇及油中更易迁移,当迁移时间在10天内时,3种目标物的迁移幅度存在一定差异,整体趋势均为随着温度和时间的增加而升高。当迁移温度不大于40℃时,氯乙烯和偏二氯乙烯在1h后均有较低含量的检出,而环氧氯丙烷在4h内仍未检出,表明环氧氯丙烷在低温下的迁移风险比氯乙烯、偏二氯乙烯低。

A headspace-gas chromatography was developed to detect the migration amount in food simulates of vinyl chloride,vinylidene chloride and epichlorohydrin in PVC packaging material.The samples were extracted by N,N-dimethylacetamide and purified by headspace at 80℃.The three targeted substances were separated by polar chromatographic column HP-INNOWAX and the migration amount was determined by ECD detector.The mass concentration of vinyl chloride,vinylidene chloride and epichlorohydrin had a good linear relationship with the chromatographic peak area in the range of 0.4-2.0 mg/L,the correlation coefficients were all more than 0.998,and the quantification limit of the method was 0.02 mg/kg.The recoveries of blank samples spiking were 80.5%-87.8%,and the relative standard deviations of the determination results were 2.5%-5.6%(n=6).Chloroethylene,vinylidene chloride and epichlorohydrin were more likely to migrate in alcohols and oils.When the migration time was within 10 days,the migration ranges of the three targets substances were different,and the overall trend showed that the total migration amount was increased with the increase of temperature and time.When the migration temperature was not more than 40℃,both vinyl chloride and vinylidene chloride had lower levels of detection after 1 hour,while epichlorohydrin had not been detected within 4 hours,indicating that the migration risk of epichlorohydrin was lower than that of vinyl chloride and vinylidene chloride at low temperatures.