为了测试本方法的重现性,将九种脂溶性维生素分别进行六次进样,如图4所示。重现性统计数据已概括在表1中。保留时间的相对标准差(RSDs)小于0.25%。在峰面积方面,九种脂溶性维生素中,有七种的RSDs小于1%。第一个峰(维生素A乙酸盐)的RSD稍大,这是因为随着进样次数的增加,基线有所上升。不管怎样,重现性都应满足质量监测的要求,其通常要求某一测试方法的重现性公差为±20%。3
结论
在本应用纪要中,我们阐述了利用单次进样UPC2法,在四分钟内,将九种脂溶性维生素同时分离的方法。经过六次重复进样得知,九种物质的保留时间的RSD均小于0.25%,峰面积的RSD均小于3%(在大多数情况下<1%)。使用UPC2方法,只需进行一次进样就可将混合物中的各种脂溶性维生素分析完毕,而不需要像LC法那样进行多次操作,从而极大地减少了实验室的工作量。UPC2方法所需时间是传统分析方法的四分之一至十分之一。由于UPC2分析法分析速度较快,因此适于食品企业/营养补充剂企业等分析量通常较大的法规依从性监测。
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