对毛细管电泳法和亲合液相色谱法测定保健食品中免疫球蛋白G的改进
Modifications for the Methods of CE and Affinity LC Determination of Immunoglobulin G in Health-care Foodstuffs
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摘要: 对现行的毛细管电泳法和亲合液相色谱法测定保健食品中免疫球蛋白G(IgG)的方法作了两方面的改进:① 在样品的预处理方面,采用加入稀乙酸使酪蛋白沉淀析出并用离心法预以分离;② 在亲合液相色谱测定方法方面,用内径较大(0.51 mm)的不锈钢管道系统代替了原有的系统,使系统的反压值下降至276 kPa,达到与免疫亲合色谱柱的耐压最大值300 kPa相匹配.改进后的方法的线性范围在200~2 000 mg·L-1之间.在分别加入100,300 mg·L-1标准IgG溶液的浓度水平上做了回收试验,测得方法的回收率和相对标准偏差(n=5)依次为112%和97%以及4.2%和3.9%.13种保健食品样品中IgG含量的亲合液相色谱法测定结果与毛细管电泳法的测定结果相一致.Abstract: Conventional methods of capillary electrophoretic and LC (with affinity column) determination of immunoglobulin G (IgG) in health-care foodstuffs were modified in 2 respects,① sample pretreatment was modified by precipitating casein with dilute acetic acid and removing by centrifugation;② stainless steel tubing with wider bore of 0.51 mm was used in the LC manifold system instead of the original in order to reduce the back pressure of the system to a lower value of 276 kPa to meet for the value of tolerable pressure of the immuno-affinity chromatographic column of 300 kPa.For the modified affinity LC method,linearity range was found between 200-2 000 mg·L-1 of IgG,and values of recovery of the method found by addition of standard IgG at concentration levels of 100 and 300 mg·L-1 were 112% and 97% with values of RSD′s (n=5) 4.2% and 3.9%,respectively.Analytical results of 13 health-care food samples found by the modified method were found to be in consistency with the CE method.