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目的建立一种从含有磨砂成分的化妆品中稳定分离、测定聚乙烯微珠的方法并观察其形状和粒径。方法利用聚乙烯与两种分散溶液(氯化钠溶液和乙腈)的相对密度差异,分离化妆品中的聚乙烯微珠,重量法测定其含量,采用显微镜观察其形态及粒径。结果化妆品中聚乙烯微珠的加标回收率为93.2%~98.2%,相对标准偏差(RSD)0.16%~2.81%。标签上标明含有微珠的14种市售样品中均能分离出聚乙烯微珠,含量为0.11%~7.76%,粒径范围100~200μm,形状基本规则,颜色主要为蓝色和白色。结论该方法稳定、简便,可以满足密度小于1 g/cm~3的聚乙烯微珠的分离。
OBJECTIVE To establish a method for the stable separation and determination of polyethylene microbeads from cosmetics containing scrubs and to observe their shape and particle size. Methods Polyethylene beads in cosmetics were isolated by the relative density difference between polyethylene and two kinds of dispersion solutions (sodium chloride solution and acetonitrile). The content of them was determined by gravimetric method. The morphology and particle size were observed by microscope. Results The spiked recoveries of polyethylene beads in cosmetics ranged from 93.2% to 98.2% with relative standard deviations (RSDs) 0.16% -281%. Polyethylene beads can be isolated from 14 kinds of commercial samples with microbeads on the label, the content is 0.11% ~ 7.76%, and the particle size is in the range of 100 ~ 200μm. The basic rules are as follows: the color is mainly blue and white. Conclusion The method is stable and simple and can be used for the separation of polyethylene beads with density less than 1 g / cm ~ 3.