Simultaneous extraction and preconcentration of two dyes with the same color from food samples by dual gel electro-membrane and determination by spectrophotometric method

Abstract

In this study, the dual gel electromembrane extraction (G-EME) method coupled with UV–Vis spectrophotometry was developed to monitor the trace amount of Tartrazine (Tt) and auramine O (AO) in food samples. These dyes have different acidic and basic properties, but their colors are the same. The main driving forces of the dual G-EME are electro-migration and electroendosmosis (EEO). Tt as acidic and AO as basic analyte from 10 mL aqueous sample solution (pH 5.27) with a voltage of 65 V and a time of 29 min were extracted into 600 µL acidic (pH 9) and basic (pH 4) acceptor solution after passing through the agar membrane. The parameters, including the agar gel concentration (% w/v), the thickness of the agar gel, the pH of the gel, and the acceptor phases were optimized by one factor at a time also the design of the Experiment program was used to analyze and optimize the parameters such as the pH of the donor phase, voltage, time and stirring rate. Under the optimal conditions, the linear range for both dyes Tt and AO was 0.05–2.0 μg mL−1 with R2 > 0.99, the detection limits were 0.0256 and 0.0310 μg mL−1 and % recovery 85.0–111 and 91.7–112 respectively. Finally, the proposed method was successfully applied to the determination of Tt and AO in food samples. This novel approach offers a sensitive and accurate way to monitor the presence of these dyes in food products, which can be crucial for ensuring food safety and quality control.