Dados do Trabalho

Título

EVALUATION OF THE SUSTAINABILITY OF A METHOD FOR DETERMINING POLYPHENOLS IN COCOA BY HPLC USING THE ECO-SCALE

Introdução

The Eco-Scale is an analytical tool designed to assess the sustainability of analytical methods by applying the 12 principles of green chemistry. It quantifies the environmental impact with a total score of 100, from which points are deducted for factors such as energy consumption, solvent use, waste production, safety, and health impact. This study employed the Eco-Scale to evaluate the sustainability of an analytical method for determining polyphenols in cocoa samples.

Material e Métodos

Cocoa extracts were prepared using organic solvents combined with water, specifically methanol (50:50), acetonitrile, and ethanol, with a gradual reduction of the organic solvent until reaching 100% water. These extracts were analyzed using high-performance liquid chromatography (HPLC-DAD), with an emphasis on chromatographic peak resolution and area.

Resultados e Discussão

The combinations of water with methanol and ethanol proved to be the most efficient. However, the water and ethanol solution (88:12) was ultimately selected as the optimal extraction solvent due to its superior solubility characteristics and better environmental score. For chromatographic separation, the ideal mobile phase was found to be water acidified with 0.1% acetic acid at pH 3.0 combined with methanol (75:25). While this combination provided good chromatographic performance, it did reduce the overall Eco-Scale score due to the use of methanol, a less environmentally friendly solvent. The final method scored 72 points on the Eco-Scale, classifying it as an "excellent green analysis."

Conclusão

Several factors contributed positively to this high score, particularly the miniaturization of the extraction method. This miniaturization allowed for a significant reduction in sample size without compromising representativeness, thereby enabling the use of smaller volumes of solvent. Although HPLC is traditionally associated with high solvent consumption, this method achieved a strong Eco-Scale score due to its short chromatographic run time (13 minutes), the increased proportion of aqueous components in the mobile phase, and a low flow rate. These factors minimized solvent waste and reduced the overall environmental impact, clearly demonstrating that the method is both efficient and environmentally sustainable. This study highlights the potential of applying the Eco-Scale in the development of green analytical methods, particularly in fields where environmental sustainability is a priority.