Extraction of anthocyanins with natural deep eutectic solvents and application in aluminum quantification by digital image colorimetry

• Grant number: 25/06997-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2025
• End date: July 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Analytical Chemistry
• Principal Investigator: Orlando Fatibello Filho
• Grantee: Ana Karoline Alvarenga Guerra
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Aluminum is present in natural sources (water and soil) and widely distributed in the environment due to anthropogenic activities. Although considered relatively safe, its accumulation in the human body may lead to various health issues, such as neurological damage and bone alterations. Traditional analytical methods for aluminum determination, such as Flame Atomic Absorption Spectrometry (FAAS) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), offer remarkable sensitivity and precision. However, these methods are time-consuming and do not allow real-time or even in-site determinations due to their bulky instrumentation and laborious sample preparation steps. Compared to other analytical methods, the colorimetric approach offers significant advantages, including cost-effectiveness, simplicity, and portability; however, some reagents and solvents used in these procedures have a potentially substantial impact on the environment. Alternatively, anthocyanins are biocompatible natural pigments that change color when complexed with metal cations, making them excellent reagents for metal detection. In this context, the aim of this project is to use of anthocyanin-rich crude extracts obtained with natural deep eutectic solvents (NADES) for the determination of Al³¿ using digital image colorimetry (DIC). Choline chloride-based NADES, combined with different hydrogen bond donors (urea, glucose, and citric acid) will be prepared and evaluated as extraction solvents of anthocyanins from different vegetal sources (black bean, blackberry, and jambolan). The crude extracts will be evaluated for the determination of Al3+ in antiperspirants and antacids samples. The quantification of aluminum is based on the measurement of the color changes that occur when Al3+ complexes with anthocyanins. The images will be captured with a smartphone and analyzed using a free web app (Trigit) for colorimetric analysis. This project could contribute to the development of a simple and rapid method for the determination of aluminum in different matrices, in accordance with the principles of green chemistry.