Hau Fung Cheung Rodney, Morrison Paul D, Small Darryl M, Marriott Philip J
Applied Chemistry, School of Applied Sciences, RMIT University, GPO Box 2476V, Melbourne 3001, Victoria, Australia.
J Chromatogr A. 2008 Dec 5;1213(1):93-9. doi: 10.1016/j.chroma.2008.09.098. Epub 2008 Oct 4.
A single enzyme treatment with alpha-amylase, prior to the quantification of added folic acid (FA) in fortified instant fried Asian noodles with analysis performed by capillary zone electrophoresis (CZE) and reversed-phase high performance liquid chromatography (RP-HPLC) with UV detection, is described. The method was validated and optimized for capillary electrophoresis (CE) with separation achieved using a 8 mM phosphate-12 mM borate run buffer with 5% MeOH at pH 9.5. FA was well separated from matrix components with nicotinic acid (NA) employed as an internal standard. In a comparative study, separation of FA was performed using HPLC with a mobile phase consisting of 27% MeOH (v/v) in aqueous potassium phosphate buffer (3.5 mM KH(2)PO(4) and 3.2 mM K(2)HPO(4)), pH 8.5, and containing 5 mM tetrabutylammonium dihydrogen phosphate as an ion-pairing agent. For both methods, excellent results were obtained for various analytical parameters including linearity, accuracy and precision. The limit of detection was calculated to be 2.2 mg/L for CE without sample stacking and 0.10 mg/L with high performance liquid chromatography (HPLC). Sample extraction involved homogenization and enzymatic extraction with alpha-amylase. Results indicated that FA was stable during four main stages of instant fried noodle manufacturing (dough crumbs, cut sheets, steaming and frying).
本文描述了一种在通过毛细管区带电泳（CZE）和带紫外检测的反相高效液相色谱（RP-HPLC）分析强化即食亚洲炒面中添加叶酸（FA）的定量之前，用α-淀粉酶进行单一酶处理的方法。该方法针对毛细管电泳（CE）进行了验证和优化，使用pH 9.5的8 mM磷酸盐-12 mM硼酸盐运行缓冲液和5%甲醇实现分离。FA与基质成分能很好地分离，使用烟酸（NA）作为内标。在一项对比研究中，使用HPLC进行FA的分离，流动相由含5 mM磷酸二氢四丁铵作为离子对试剂的磷酸钾水溶液（3.5 mM KH₂PO₄和3.2 mM K₂HPO₄）中的27%甲醇（v/v）组成，pH 8.5。对于这两种方法，在包括线性、准确度和精密度等各种分析参数方面都获得了优异的结果。CE在不进行样品堆积时的检测限计算为2.2 mg/L，高效液相色谱（HPLC）的检测限为0.10 mg/L。样品提取包括用α-淀粉酶进行匀浆和酶提取。结果表明，FA在即食炒面制造的四个主要阶段（面团碎粒、切片、蒸煮和油炸）中是稳定的。
