An Ultraviolet–Visible Spectrophotometric Approach to Establish a Method for Determining the Presence of Rhodamine B in Food Articles

Rhodamine B, a synthetic dye, is used as a food additive to impart color to different foodstuffs to attract buyers. The aim of this study was to develop and validate an ultraviolet–visible spectrophotometric method for the identification and estimation of rhodamine B in rhodamine B-adulterated food articles. Upon reaction with HCl, rhodamine B produces a rose-pink color, exhibiting maximum absorption at 556 nm. The linearity, precision, and accuracy were analyzed statistically for validation. An aliquot of rhodamine B obeyed the Beer–Lambert law between 2 and 20 μg/mL and exhibited a linear regression curve with a correlation coefficient (R2) of 0.9991. The limit of detection and limit of quantification were 1.15 and 3.5 μg/g, respectively. The detection was further confirmed by performing thin layer chromatography and 1H nuclear magnetic resonance of the sample with the pure rhodamine B. The proposed method for the determination and estimation of rhodamine B as a food coloring agent in this report is accurate and precise.