One-pot derivatization spectrofluorimetric method for detection of aspartame in sweetener commercial tablets and soft drinks: Greenness assessments of the methodology

Aspartame is an artificial sweetener used in drinks and many foods. International Agency for Research on Cancer classified aspartame as possibly carcinogenic to humans (IARC Group 2B). In this study, a sensitive and selective spectrofluorimetric method was developed to detect aspartame. The method is based on switching on the fluorescence activity of aspartame upon its condensation with O-phthalaldehyde (Roth's reaction) in the presence of 2-mercaptoethanol. The reaction product was detected fluorometrically at λ_em of 438 nm after λ_ex of 340 nm. All reaction conditions required to yield the optimal fluorescence intensity were observed and investigated. Furthermore, the approach was validated according to ICH guidelines. Upon plotting the concentrations of aspartame against their associated fluorescence intensity values, the relationship between the two variables was linear within the range of 0.5–3.0 μg/mL. Furthermore, the method was employed to analyze the quantity of aspartame in commercial packages and soft drinks with an acceptable level of recovery. In addition, the Green Solvents Selecting Tool, Complementary Green Analytical Procedure Index, and the Analytical Greenness Metric tool were used to evaluate the sustainability and the greenness of the developed methodology.