聚合离子液体为添加剂的毛细管电泳法用于快速高效分离饮料中7种有机酸

Highly efficient and rapid capillary electrophoretic analysis of seven organic acid additives in beverages using polymeric ionic liquid as additive

用一种聚合离子液体(聚1-乙烯基-3-丁基咪唑溴盐)为添加剂,以毛细管电泳法(CE)快速直接分离饮料中7种有机酸(丙二酸、酒石酸、抗坏血酸、反丁烯二酸、苯甲酸、山梨酸和柠檬酸)。详细考察了几种影响分离效果的条件,最佳背景电解质条件是125 mmol/L磷酸二氢钠缓冲液(pH 6.5)添加0.01 g/L聚合离子液体。7种分析物在4 min内能够快速高效分离(105 000～636 000塔板/m),迁移时间的标准偏差(n=3)都不大于0.021 3 min。7种分析物的检出限(以信噪比为3计)在0.001与0.05 g/L之间。这种方法被应用于一种美年达葡萄汁饮料中的有机酸检测。柠檬酸钠、苯甲酸和山梨酸被检测出,含量分别是2.64、0.10和0.08 g/L,其加标回收率分别为100.3%、100.7%和131.7%。该方法简单、快速、低廉,可以用作食品中有机酸添加剂的检测。

A new capillary electrophoretic method for the rapid and direct separation of seven organic acids in beverages was developed,with poly（1-vinyl-3-butylimidazolium bromide） as the reliable background electrolyte modifier to reverse the direction of anode electroosmotic flow（EOF） severely.Several factors that affected the separation efficiency were investigated in detail.The optimal running buffer consisted of 125 mmol/L sodium dihydrogen phosphate（pH 6.5） and 0.01 g/L poly（1-vinyl-3-butylimidazolium bromide）.Highly efficient separation（105 000 to 636 000 plates/m） was achieved within 4 min and standard deviations of the migration times（n=3） were lower than 0.0213 min under optimal conditions.The limits of detection（S/N=3） ranged from 0.001 to 0.05 g/L.The present method was applied to determine a beverage sample（Mirinda） for sodium citrate,benzoic acid and sorbic acid with concentration of 2.64,0.10 and 0.08 g/L,respectively.The recoveries of the three analytes in the sample were 100.3%,100.7% and 131.7%,respectively.The method is simple,rapid,inexpensive,and can be applied to determine organic acids as additives in beverages.