Law Wai Siang, Kubán Pavel, Zhao Jian Hong, Li Sam Fong Yau, Hauser Peter C
Department of Chemistry, National University of Singapore, Republic of Singapore.
Electrophoresis. 2005 Dec;26(24):4648-55. doi: 10.1002/elps.200500437.
The separation and detection of commonly used preservatives (benzoate, sorbate) and vitamin C by both conventional CE and microchip electrophoresis with capacitively coupled contactless conductivity detection is presented. The separation was optimized by adjusting the pH-value of the buffer and the use of hydroxypropyl-beta-CD (HP-beta-CD) and CTAB as additives. For conventional CE, optimal separation conditions were achieved in a histidine/tartrate buffer at pH 6.5, containing 0.025% HP-beta-CD and 0.1 mM CTAB. LOD ranged from 0.5 to 3 mg/L (S/N = 3) and the RSDs for migration time and peak area were less than 0.1 and 2%, respectively. A considerable reduction of analysis time can be accomplished by using microchip electrophoresis without significant loss in sensitivity under optimal separation conditions. A histidine/tartrate buffer at pH 6.5, incorporating 0.06% HP-beta-CD and 0.25 mM CTAB, gave detection limits ranging between 3 and 10 mg/L and satisfactory reproducibilities of < or =0.4% for the migration time and < or =3.5% for the peak area. The methods developed are useful for the quantitative determination of food additives in real samples such as soft drinks and vitamin C tablets.
本文介绍了采用常规毛细管电泳（CE）和具有电容耦合非接触电导检测的微芯片电泳对常用防腐剂（苯甲酸盐、山梨酸盐）和维生素C进行分离与检测的方法。通过调节缓冲液的pH值以及使用羟丙基-β-环糊精（HP-β-CD）和十六烷基三甲基溴化铵（CTAB）作为添加剂对分离条件进行了优化。对于常规CE，在pH 6.5的组氨酸/酒石酸盐缓冲液中实现了最佳分离条件，该缓冲液含有0.025%的HP-β-CD和0.1 mM的CTAB。检测限范围为0.5至3 mg/L（信噪比=3），迁移时间和峰面积的相对标准偏差分别小于0.1%和2%。在最佳分离条件下，使用微芯片电泳可显著缩短分析时间，且灵敏度无明显损失。在pH 6.5的组氨酸/酒石酸盐缓冲液中加入0.06%的HP-β-CD和0.25 mM的CTAB，检测限在3至10 mg/L之间，迁移时间的重现性令人满意，小于或等于0.4%，峰面积的重现性小于或等于3.5%。所开发的方法可用于定量测定软饮料和维生素C片等实际样品中的食品添加剂。
