A New Green In Situ Effervescent CO₂-Table-Induced Switchable Hydrophilicity Solvent Extraction Method of Rhodamine B in Food and Soft Drink Samples

Background: A new and simple effervescent CO₂-table-induced switchable hydrophilicity solvent extraction method (CI-SHS) was used for the preconcentration of rhodamine B (RB). Objective: The main theme of the proposed method to disperse green solvent by in situ CO₂-table system overcome on the contamination and to avoid the dispersion by using different chemicals. Methods: Switchable hydrophilicity solvent (N, N-Dimethyl cyclohexylamine) was dispersed in an aqueous solution by reaction of CO₂-table of sodium carbonate and citric acid to enhance the contact area between two medium, which radically improved the extraction capacity of the RB from aqueous medium to switchable solvent. The phase separation was achieved by simple heating not by centrifugation that makes a change on hydrophilicity to hydrophobicity. The supernatant-enriched RB- N, N-Dimethyl cyclohexylamine phase was withdrawn and injected into the UV glass cells. The absorbance was measured at 542. Results: Limit of detection and enhancement factor were achieved to be 0.042 and 50 mg/L. Validity and accuracy of the method verified by analysis of real samples by the spiking addition method. The relative standard deviation was obtained at 3.2%. The method was applied to food and soft drink samples. Conclusions: This method offers high sensitivity, selectivity, accuracy, and precision for the separation, preconcentration, and spectrophotometric determination of RB. Simple, fast, low-cost, and green extraction method was developed. Highlights: High enrichment factor and lower detection limits were observed in this microextraction method. Present method is sensitive, selective, very accurate, and precise.