Method Validation and Analysis of Vitamin C Content in Facial Brightening Creams Distributed in Bengkulu City Using UV-Vis Spectrophotometry

Abstract

Vitamin C is widely used in facial brightening creams as an antioxidant, collagen-supporting agent, and inhibitor of melanin formation, yet the actual amount in marketed products is not always quantitatively declared. To determine vitamin C levels in five facial brightening creams marketed in Bengkulu City and to evaluate the validity of the UV-Vis spectrophotometric method. Samples were purposively selected based on BPOM authorization and vitamin C labeling. Qualitative identification used methylene blue, FeCl3, and KMnO4, while the quantitative analysis was performed using UV-Vis spectrophotometry. Validation covered linearity, precision, accuracy, LOD, and LOQ. All samples tested positive for vitamin C. Mean levels in samples A-E were 0.9010%, 0.1673%, 8.0605%, 7.1276%, and 0.00785%, respectively. The mean linearity R² was 0.99960, %RSD was 1.76044%, recovery ranged from 97.999% to 102.451%, LOD was 0.32812 ppm, and LOQ was 0.99430 ppm. The UV-Vis spectrophotometric method met the evaluated validation parameters and was suitable for determining vitamin C in facial brightening cream matrices under the study conditions.