基体匹配校正-顶空-气相色谱法测定食品塑料包装材料中挥发性有机物

采用顶空-气相色谱法测定了食品用软质塑料包装材料中具有代表的10种挥发性有机物(VOC′s),包括甲苯、乙酸乙酯、2,4-戊二酮、2-乙基-1-己醇、1-壬醛、癸烷醛、十二烷醛、癸烷、正辛烷及十二烷,并用基体匹配法抵消了样品本身的基体干扰。从待分析样品(包装膜)裁取约100cm2大小片样置于真空烘箱中,于90℃烘24h,此片试样即可作为空白基质,再加入一定量的上述VOC标准溶液制备校准曲线。另取同一样品一片,剪碎后移入顶空瓶中,立即盖紧,在100℃平衡30min。方法中用HP-INNOWAX色谱柱在20℃～220℃温度区间程序升温,对各VOC进行分离,采用火焰离子化检测器检测。测得10种VOC′s的检出限(3S/N)在0.2～2.0μg.dm-2之间。另测得平均回收率及相对标准偏差(n=6)分别在82.5%～97.6%和0.9%～14.0%之间。

Head-Space-GC Determination of Volatile Organic Compounds in Plastic Packaging Materials for Foodstuffs with Matrix Matching Calibration

Ten volatile organic compounds(VOC′s),i.e.,toluene,ethyl acetate,2,4-pentanedione,2-ethyl-1-hexanol,1-nanaldehyde,decanecarbaldehyde,dodecanacarbaldehyde,decane,octane and dodecane in soft plastic packaging materials were determined by head-space gas chromatography using matrix matching calibration to compensate the matrix interference.A representative portion of the sample(packaging film,ca.100 cm2) was taken and stoved in a vacuum oven at 90 ℃ for 24 h.This portion of the sample was cut and used as blank matrix for preparation of calibration curve and definita amounts of standard solutions of the 10 VOC′s wer added to it and treated in the same way as the sample.A similar portion of the sample was cut and transferred into the headspace bottle,closed the bottle immediately and equilibrized at 100 ℃ for 30 min.HP-INNOWAX chromatographic column was used for separation at programed temperature elevation from 20 ℃ to 220 ℃.FID was adopted for determination.Detection limits(3S/N) found for the 10 VOC′s were ranged from 0.2 to 2.0 μg·dm-2.Values of recovery and RSD′s(n=6) were in the ranges of 82.5%-97.6% and 1.0%-14.0% respectively.