Lerma-García María Jesús, Simó-Alfonso Ernesto F, Ramis-Ramos Guillermo, Herrero-Martínez José M
Department of Analytical Chemistry, Faculty of Chemistry, University of Valencia, Valencia, Spain.
Electrophoresis. 2008 Nov;29(22):4603-11. doi: 10.1002/elps.200800247.
A method for the determination of sterols in vegetable oils by CEC with UV-Vis detection, using methacrylate ester-based monolithic columns, has been developed. To prepare the columns, polymerization mixtures containing monomers of different hydrophobicities were tried. The influence of composition of polymerization mixture was optimized in terms of porogenic solvent, monomers/porogens and monomer/crosslinker ratios. The composition of the mobile phase was also studied. The optimum monolith was obtained with lauryl methacrylate monomer at 60:40% (wt:wt) lauryl methacrylate/ethylene dimethacrylate ratio and 60 wt% porogens with 20 wt% of 1,4-butanediol (12 wt% 1,4-butanediol in the polymerization mixture). Excellent resolution between sterols was achieved in less than 7 min with an 85:10:5 v/v/v ACN-2-propanol-water buffer containing 5 mM Tris at pH 8.0. The limits of detection were lower than 0.04 mM, and inter-day and column-to-column reproducibilities at 0.75 mM were better than 6.2%. The method was applied to the determination of sterols in vegetable oils with different botanical origins and to detect olive oil adulteration with sunflower and soybean oils.
已开发出一种采用基于甲基丙烯酸酯的整体柱，通过毛细管电色谱结合紫外-可见检测来测定植物油中甾醇的方法。为制备色谱柱，尝试了含有不同疏水性单体的聚合混合物。从致孔溶剂、单体/致孔剂和单体/交联剂比例方面对聚合混合物的组成影响进行了优化。还研究了流动相的组成。以甲基丙烯酸月桂酯单体，在甲基丙烯酸月桂酯/二甲基丙烯酸乙二醇酯比例为60:40%（重量比）且致孔剂为60重量%以及20重量%的1,4-丁二醇（在聚合混合物中1,4-丁二醇为12重量%）的条件下获得了最佳整体柱。在含有5 mM Tris（pH 8.0）的85:10:5 v/v/v乙腈-2-丙醇-水缓冲液中，不到7分钟就能实现甾醇之间的出色分离。检测限低于0.04 mM，在0.75 mM时日间和柱间重现性优于6.2%。该方法应用于测定不同植物来源植物油中的甾醇，并用于检测橄榄油中掺假的向日葵油和大豆油。
