Propylene Glycol as a Promising Eluent in Green Reversed Phase Liquid Chromatographic Separation of Ascorbic Acid and Glutathione in Effervescent Tablets

Exploring green organic solvents is a global demand. Most of the currently used solvents pose some concerns regarding environmental sustainability and occupational health risks. In this work, propylene glycol was employed for the first time as a green solvent for mobile phase preparation in the reversed phase chromatographic separation of a mixture of two antioxidants, glutathione and ascorbic acid. The slight viscosity of propylene glycol was manipulated by using water as a co-fluidizing agent to facilitate pumping. Method optimization was performed using factorial design experimental Expert 13® Software (Minneapolis, MN, USA) to achieve the maximum resolution and the minimum run time. The reported method was properly validated according to the International Conference on Harmonization criteria at the linearity range of 1–500 µg/mL, with acceptable accuracy and precision for both drugs. The method was effectively applied for the quantification of both drugs in their commercial pharmaceutical formulation. The proposed method was assessed for environmental and operator safety by means of global tools like AGREE and MoGAPI and has proved high degrees of greenness. Propylene glycol has several benign properties, such as low volatility, less toxicity, compatibility with UV detectors and very low flammability, that will soon assemble it as a promising alternative for the conventionally used solvents.