Pontos de carbono a partir de Opuntia inermis para determinação espectrofluorimétrica de cobre(II) em cachaça artesanal

Abstract

Cachaça is a widely consumed alcoholic beverage throughout Brazil, losing only to beer. This consumption sparks reflection on the conditions and facilities in which the production of this beverage occurs, since a series of organic and inorganic contaminants can be present. Among these contaminants, copper (II) has gained prominence because it is frequently found at levels higher than 5.0 mg L-1, the limit allowed by law. This shows the need for an efficient monitoring of copper concentrations in beverages and food. For the above, this work sought to evaluate the copper contents in artisanal cachaças marketed in the city of Serra Talhada, Pernambuco. Proposing a methodology based on the synthesis of fluorescent carbon points (PC) to act as a chemical sensor in the presence of copper (II). The PCs were synthesized from the hydrothermal treatment of the juice of the cactus palm in microwave oven. Its optical properties were evaluated by molecular absorption spectra in UV-Vis and molecular fluorescence, and its particle distribution was evaluated by transmission electron microscopy. The PCs showed quantum fluorescence yield of 23.2%. The limits of detection and quantification were 0.36 mg L-1 and 1.18 mg L-1 , respectively. The correlation between the fluorescence intensity of PC-Cu (II) solutions with concentration of Cu (II) present, exposes the success of the nanomaterial as a chemical sensor and fluorescent reagent. This correlation is supported by the linear behavior presented by the analytical curve. The carbon points from the palm have been shown to be a versatile reagent for determination of copper concentrations, which makes the proposed method an alternative to be further explored.