Simultaneous separation and quantification of acidic and basic dye specimens via a dual gel electro-membrane extraction from real environmental samples

In this work, an environmentally friendly and easy-in-performance dual gel electro-membrane extraction approach (dual G-EME) was combined with high performance liquid chromatography. Method was arranged for parallel isolation, enrichment and determination of brilliant green (BG) and reactive red (RR), serving as model basic and acidic dyes, respectively. A DIY (do-it-yourself) agarose-based gel membrane was fabricated, and served as green and highly selective filtering item. The extractions were hazards-free (i.e., there was no need for organic solvents or toxic regents) and membrane assembly is highly degradable as being of fully natural character. Thereby, setup has met the requirements of being a green analytical chemistry technique. By using an electric potential of 50 V during 20 min extraction time, the positively charged BG and negatively charged RR migrated selectively from a 7.0 mL aqueous sample (pH 7.0) to the 500 μL cathodic (pH 4.0) and 500 μL anodic (pH 9.0) aqueous acceptor phases, respectively. Under the optimal conditions, limits of detection were 0.020 and 0.025 ng mL−1, and extraction recoveries were of 75–78% and 67–71% for BG and RR, respectively. The linearity was in the range of 0.06–1.0 μg mL−1 with correlation coefficient higher than 0.996, obtained for both model analytes. Finally, the methodology was successfully applied for parallel quantification of BG and RR in complex environmental samples.