Development and Validation of a Method for the Analysis of Zinc Oxide in Cosmetic Matrices by Flame Atomic Absorption Spectroscopy

Abstract

A fast and simple method for the extraction and Flame Atomic Absorption Spectroscopy (FAAS) quantification of ZnO in different cosmetic matrices, including lipsticks, water-in-oil foundations, and oil-in-water creams, was developed and validated, according to the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) and the United States Pharmacopeial Convention guidelines. The sample preparation consisted of an ultrasound-assisted ethanolic extraction of ZnO followed by digestion with 1 M nitric acid (HNO3). Samples were analyzed by Flame Atomic Absorption Spectroscopy (FAAS). Specificity, linearity, the limit of detection (LOD), the limit of quantification (LOQ), sensitivity, precision, and accuracy parameters were studied. The robustness of the method was evaluated with a five-variable Youden–Steiner model. The method was specific for ZnO, and the extraction procedure did not affect the stability of the signal compared to the background. The method was linear in the range 0.2–1.0 mg/L with LOD/LOQ values equal to 0.0156 (mg·L−1)/0.0473 (mg·L−1), 0.0098 (mg·L−1)/0.0297 (mg·L−1), 0.0113 (mg·L−1)/0.0341 (mg·L−1), and 0.0131 (mg·L−1)/0.0397 (mg·L−1), respectively, for raw material, lipstick, liquid foundation, and emulsion matrices. Regarding precision, the %RSD values were below 3.0% for repeatability and intermediate precision. Global reproducibility RSD was below 8.0% for all matrices. The percentage of recovery was not statistically different from 100% in all cases. The final concentration was found to be a critical variable for all matrices except for the raw material. The variables associated with the extraction step (ethanol volume, bath temperature, and extraction time) were critical in the extraction of liquid foundations and cream emulsions. The method reduces the number and concentration of mineral acids spent on the digestion of ZnO, and its application is extendable to raw materials. This development is an adequate tool for routine analysis and cosmetic quality control of chemically different products that contain ZnO as ultraviolet radiation (UV) filter, to guarantee regulatory compliance and ensure the safety and efficacy of products delivered to consumers.

Analisis logam berat kadmium (Cd) pada sampel pangan segar asal tumbuhan (PSAT) di BBKP Makassar

“…Logam Cd memliki penyebaran yang luas di alam. Berdasarkan sifat fisiknya, logam Cd memiliki sifat yang lunak yang mudah dibentuk dimana logam tersebut akan kehilangan kilapnya ketika berada dalam udara yang basah atau lembapserta cepat akan mengalami kerusakan bila terkena uap amoniak (NH3) dan sulfur hidroksida (SO2) [6].…”

“…Dalam tubuh manusia, Cd paling sering membuat kerusakan pada kedua organ ini, serta gonad, paru-paru dan tulang. Terlebih lagi, itu menyebabkan dampak penyebab kanker, memulai pertumbuhan ganas dari prostat, ginjal, pankreas, dan testis [6]. Dalam kasus sayuran dan buah-buahan, sumber kontaminasi dengan logam berat mungkin dari lingkungan dimana kultivasi dilakukan [11].…”