Artigo
A digital image method of spot tests for determination of copper in sugar cane spirits
Autor
Pessoa, Kenia Dias
Suarez, Willian Toito
Reis, Marina Ferreira dos
Franco, Mathews de Oliveira Krambeck
Moreira, Renata Pereira Lopes
Santos, Vagner Bezerra dos
Institución
Resumen
In this work the development and validation of analytical methodology for determination of copper in sugarcane spirit
samples is carried out. The digital image based (DIB) method was applied along with spot test from the colorimetric
reaction employing the RGB color model. For the determination of copper concentration, it was used the cuprizone -
a bidentate organic reagent - which forms with copper a blue chelate in an alkaline medium. A linear calibration
curve over the concentration range from 0.75 to 5.00 mg L^−1 (r2 = 0.9988) was obtained and limits of detection
and quantification of 0.078 mg L^−1 and 0.26 mg L^−1 were acquired, respectively. For the accuracy studies, recovery per-
centages ranged from 98 to 104% were obtained. The comparison of cooper concentration results in sugar cane spirits
using the DIB method and Flame Atomic Absorption Spectrometry as reference method showed no significant differ-
ences between both methods, which were performed using the paired t-test in 95% of confidence level. Thus, the spot
test method associated with DIB allows the use of devices as digital cameras and smartphones to evaluate colorimetric
reaction with low waste generation, practicality, quickness, accuracy, precision, high portability and low-cost.