An arginine selective colorimetric assay using azobenzothiazole-polyene based dipolar molecular receptor

A new simple colorimetric method for selective determination of arginine was developed using an azobenzothiazole-polyene dye. The benzothiazole moieties of the dye act as dipolar molecular receptors to arginine. Importantly, arginine could be recognized in solution with the naked eye due to the color change from orange to blue. Reproducibility of the assays was proven by calculating of the intraand inter-assay variations for the color responses and the variations were found to be 6.9 and 4.2%, respectively. Finally, the accurate measurements of arginine in real samples (commercial supplementary medicines) were achieved. In conclusion, validation of the developed method revealed excellent performance characteristics, including long life span, good arginine selectivity among a wide variety of other amino acids and long-term response stability.