Electrophoretic analysis of food dyes using a miniaturized microfluidic system

Abstract

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.

Sample preconcentration in microfluidic devices

“…Using this microchip, coupled with electrochemical detection (ED) for the separation and detection of 100-bp DNA ladders, CFs of 2.3 9 10 4 (for the 400-bp fragment) to 2.5 9 10 4 (for the 2000-bp fragment) were obtained when compared with a conventional MGE-ED analysis. If MGE separation is replaced with MEKC separation, this microchip can be also applied to the analysis of phenolic compounds (Shiddiky et al 2006), food dyes (Lee et al 2008b), and tetracycline antibiotics (Lee et al 2009b) with CFs of 5.20 9 10 3 , 1.08 9 10 4 , and 1.09 9 10 4 , respectively. One disadvantage of FASS/FASI is its poor applicability to physiological samples containing high-concentrations of salts which may greatly reduce the stacking effect.…”

Development of a Novel Electrochemical Sensor Based on a Carbon Paste Electrode Decorated with Nd2O3 for the Simultaneous Detection of Tartrazine and Sunset Yellow

“…The excessive use of TZ and SY in the manufacture of industrially produced foods has motivated the development of new methodologies for the simultaneous detection of TZ and SY. The most commonly used techniques are spectrophotometry capillary electrophoresis and high‐performance liquid chromatography (HPLC) . These reports show that these techniques are selective and sensitive but operationally expensive and require rigorous pretreatment of the samples.…”

Second order advantage in the determination of amaranth, sunset yellow FCF and tartrazine by UV–vis and multivariate curve resolution-alternating least squares

“…Therefore, the analyses have traditionally been focused on separation methods. The analytical methods frequently used for the determination of amaranth, sunset yellow and tartrazine include thin layer chromatography (TLC) [5], capillary electrophoresis (CE) [6][7][8], and mainly high-performance liquid chromatography (HPLC) [9][10][11][12]. However, some disadvantages arise from these methods, such as usage of toxic solvents, spending of time, and the need of sample pretreatments.…”