Extraction Procedures and Analytical Methods for the Determination of Methylene Blue, Rhodamine B and Crystal Violet - An Overview

Background: Dyes have been a blessing to mankind owing to their numerous applications in several industries ranging from textile, food, pharmaceuticals, and paper to leather, and many more. At the same time, these dyes pose a potential threat to mankind, when they are present beyond their permissible limits. This review covers the extraction and determination methods of dyes in different matrices. Introduction: Methylene blue (MB), rhodamine B (RB), and crystal violet (CV) are the three cationic dyes discussed in this review. These dyes can pose a potential threat to biota beyond their permissible limits. Methods: This review article mentions different analytical methods and extraction techniques involved in the determination of dyes. Result: Almost all the analytical methods reported in this article involve proper extraction of the analyte, which finds a place in this review article. Spectrophotometric and electrochemical methods are cost-effective, although the former is less sensitive than the latter. Liquid chromatography (LC) and liquid chromatography coupled with mass spectrometry (LC/MS) are capable of simultaneously determining a number of dyes. Conclusion: This review also offers a compilation of different mobile phase combinations that have been used for the quantitative analysis of these three dyes. The article also contains a list of different solvents for liquid-liquid extraction and different types of sorbent materials used during the solid-phase extraction of the reviewed dyes.