Multivariate Optimization of an Analytical Method for Bisulfite Determination in Vinegar Samples Using Digital Images

• Published in: Food analytical methods Vol. 17; no. 9; pp. 1327 - 1335
• Main Authors: de Jesus, Joseane G., dos Reis, Marcos Levi C. M., Dantas, Alailson F., Teixeira, Leonardo S. G., de S. Dias, Fabio
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.09.2024
• Subjects: Analytical Chemistry; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Food Science; Microbiology; 2,2′-Bipyridine; Full factorial design; Bisulfite; Doehlert matrix; Digital images
• ISSN: 1936-9751; 1936-976X
• DOI: 10.1007/s12161-024-02665-y

This work proposes an analytical method based on digital images to indirectly determine bisulfite in vinegar samples using the colorimetric reaction between Fe(II) and the complexing agent 2,2′-bipyridine. Optimization was conducted using a multivariate methodology. Firstly, a two-level full factorial design was performed to identify the factors with significant effects on the analytical response through a two-level full factorial design (2 3 ). The studied variables included pH, 2,2′-bipyridine concentration, and sample volume. Subsequently, a Doehlert matrix was employed to establish the optimal conditions for the significant variables. The recommended procedure involved a reaction pH of 5.7 and a 0.0038 mol L −1 2,2′-bipyridine concentration, with a sample volume of 0.75 mL. The proposed method exhibited a linear response within the range of 0.45 to 300 mg L −1 of bisulfite, with detection and quantification limits of 0.15 mg L −1 and 0.45 mg L −1 , respectively. The method’s precision, assessed through relative standard deviation, was 3.4% ( n  = 10, 1.0 mg L −1 ). Accuracy was evaluated through recovery tests, with results ranging from 97 to 114%. Furthermore, a comparison was made between the bisulfite concentrations determined using the proposed method and those obtained through a reference method based on iodometric titration. The method was successfully applied to determine bisulfite in commercial vinegar samples. The bisulfite concentration varied from (14 ± 1) mg L −1 to (261 ± 3) mg L −1 .