de Oliveira Krambeck Franco M, Dias Castro GA, Vilanculo C, Fernandes SA, Suarez WT. A color reaction for the determination of Cu
2+ in distilled beverages employing digital imaging.
Anal Chim Acta 2021;
1177:338844. [PMID:
34482892 DOI:
10.1016/j.aca.2021.338844]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 07/03/2021] [Accepted: 07/06/2021] [Indexed: 12/01/2022]
Abstract
In this work, we describe for the first time the synthesis of a thiocarbazone for the selective determination of Cu2+ in distilled beverages. The method was based on the complexation reaction of Cu2+ with the thiocarbazone, and the colored product was analyzed using a smartphone application. The thiocarbazone reacts with Cu2+ to form a 1:1 (metal:ligand) complex. The Cu2+ complex was characterized by UV, IR and NMR spectral analyses. The proposed reaction yields a yellow color, and therefore, channel B of the RGB system was used in the analysis. After optimizing the reaction conditions, an analytical curve was obtained to determine Cu2+ concentrations ranging between 0.25 and 6.75 mg L-1; the use of 400 μL sample volumes led to a relative standard deviation (n = 5) of 3.2% and a detection limit of 0.18 mg L-1. Recovery experiments were performed with sugar cane spirits, whiskies and tequilas to evaluate the accuracy of the method, and the recovery obtained ranged from 80.5 to 112.2%.
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