Lee Kyung-Sun, Shiddiky Muhammad J A, Park So-Hee, Park Deok-Su, Shim Yoon-Bo
Department of Chemistry, Pusan National University, Busan, South Korea.
Electrophoresis. 2008 May;29(9):1910-7. doi: 10.1002/elps.200700556.
A simple and sensitive on-chip preconcentration, separation, and electrochemical detection (ED) method for the electrophoretic analysis of food dyes was developed. The microchip comprised of three parallel channels: the first two are for the field-amplified sample stacking (FASS) and subsequent field-amplified sample injection (FASI) steps, while the third one is for the micellar EKC with ED (MEKC-ED) step. The food dyes were initially extracted from real samples by employing a method that was simpler, easier, and faster compared with a standard method. The extraction of the samples was characterized by UV-Vis and electrochemical experiments. The chronoamperometric detection was performed with a glassy carbon electrode coupled horizontally with the microchip at the separation channel exit. Experimental parameters affecting the analytical performance of the method were assessed and optimized. The sensitivity of the method was improved by approximately 10,800-fold when compared with a conventional MEKC-ED analysis. Reproducible response was observed during multiple injections of samples with an RSD of <7.2% (n=5). The calibration plots were linear (r2=0.998) within the range of 1.0 nM-1.0 microM for all food dyes. LODs were estimated between 1.0 and 5.0 nM, based on S/N=3, for food dyes. The applicability of the method for the analysis of food dyes in real sample was demonstrated.
开发了一种用于食品染料电泳分析的简单灵敏的芯片上预浓缩、分离和电化学检测（ED）方法。该微芯片由三个平行通道组成：前两个用于场放大样品堆积（FASS）和随后的场放大样品进样（FASI）步骤，而第三个用于带ED的胶束EKC（MEKC-ED）步骤。与标准方法相比，食品染料最初采用一种更简单、更容易且更快的方法从实际样品中提取。通过紫外可见和电化学实验对样品的提取进行了表征。计时电流检测在分离通道出口处与微芯片水平耦合的玻碳电极上进行。评估并优化了影响该方法分析性能的实验参数。与传统的MEKC-ED分析相比，该方法的灵敏度提高了约10800倍。多次进样时观察到可重复的响应，相对标准偏差（RSD）<7.2%（n=5）。所有食品染料的校准曲线在1.0 nM-1.0 microM范围内呈线性（r2=0.998）。基于信噪比（S/N）=3，食品染料的检测限估计在1.0至5.0 nM之间。证明了该方法在实际样品中分析食品染料的适用性。
