Low cost method for copper determination in sugarcane spirits using Photometrix UVC® embedded in smartphone

• Published in: Food chemistry 2022-01, Vol.367, p.130669-130669, Article 130669
• Main Authors: Böck, Fernanda C., Helfer, Gilson A., da Costa, Adilson B., Dessuy, Morgana B., Ferrão, Marco F.
• Format: Article
• Language: English
• Subjects: Cachaça; Digital image analysis; Doehlert matrix; External camera; Partial least squares
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2021.130669

•Copper determination by digital images analysis using smartphone and PhotoMetrix® application.•Different region of interest (ROI) sizes, cameras and ways of processing data were evaluated.•Accurate results were obtained using low-cost apparatus and a small reagent volumes.•The multivariate calibration by Partial Least Squares presented better results. Analysis of digital images by smartphone was used for copper quantification in sugarcane spirit (cachaça) samples through the formation of blue complex between copper and cuprizone. An experimental design was carried out to evaluate the best complexation reaction conditions. Moreover, different image acquisition procedures (external camera coupled to a smartphone or the smartphone camera) with different regions of interest sizes, distances in image acquisition, and concentration ranges of the calibration curve and the influence of processing the curve in univariate and multivariate modes, by PLS, were evaluated. The results obtained in three real samples and two spikes were compared with those of UV–Vis spectrophotometry, used as a reference method, and they show the potential of the proposed method for the accurate determination of copper. When compared to traditional techniques, the proposed method has the advantages of portability and low cost in addition to requiring a smaller amount of reagents.