Optimization of C18-Cellulose Triacetate Thin Film for Analysis of Caffeine Residue in Water

Abstract

This study report the optimal condition of an extraction method for caffeine residue analysis in water. C18 was impregnated with cellulose triacetate by using a solution casting method to produce a thin film. Optimization work was performed based on a 23-full factorial central composite design, which was subjected to salt addition, extraction time, and stirring rate as the main parameters. The optimum condition suggested by the model was as follows; salt addition (0.6 %, m/v), extraction time (11 min) and stirring rate (300 rpm). The generated model and 2-way interaction were significant at p < 0.05. Detection and quantification limits of the developed method were calculated at 0.06 and 0.21 ng/mL, respectively. The thin film displayed exceptional recovery (83.90-98.50 %) and repeatability (7.71-12.40 % RSD) at two levels of concentration.