Application of central composite design and desirability function in the optimization of spectrophotometric method for quantification of fast green FCF using a green microextraction method

The aim of this article is to develop a "switchable hydrophilicity solvent liquid phase microextraction" (SHS-LPME) for the effectual extraction of fast green FCF. Three "switchable hydrophilicity solvents" (SHSs) were practiced for the extraction of fast green FCF. The attained extract phase afterward phase separation was evaluated by UV-VIS spectrophotometry. The extraction parameters such as, SHS volume, HNO3 volume and NaOH volume, were enhanced using central composite design and desirability function. Under optimized conditions, the linear range 0.50-5.00 µg/ mL with R2 = 0.9886, limit of detection 0.341 µg/ mL, limit of quantitation 1.026 µg/ mL. The method showed a relative standard deviation (RSD) of 1.16% for 7 replicate measurements. Preconcentration and Enrichment factors were determined to be 20 and 35 respectively, indicating the method’s efficiency in enhancing fast green detection. The proposed method was applied in real samples successfully.