Determination of Methylene Blue as Toxic Contaminant in Aqueous Media using Electromembrane Microextraction Method Optimization by Experimental Design

In analytical chemistry, sample preparation before any instrumental measurement is one of the most important steps. Extraction is one of the most widely used methods of sample preparation, which concentrates the analyte and transfers it to a simpler and cleaner matrix media. Therefore, in the present work, electromembrane extraction method combined with UV–Vis spectrophotometric detection was proposed for the preconcentration and determination of methylene blue in cultivated fish samples. The optimized conditions for preconcentration step were: agarose amount 5.0% (w/v), acetic acid amount 0.10% (v/v), pH of donor and acceptor phase of 8.3 and 2, respectively, applied electric voltage 80V and extraction time of 25 min. In the optimum conditions, the precision according to relative standard deviation formula was found to be 2.3 and the linear range was 0.015-1.560 µM. Limits of detection and quantification were 4.7×10-3 and 15.4×10-3, respectively. The method validation was compared with the other methylene blue analysis techniques. The proposed method provided a rapid, sensitive, requires low sample volume, and short extraction time with high precision and accuracy which is applicable successfully for routine analysis of methylene blue contents in cultivated fish samples.