Desenvolvimento de métodos voltamétricos para a determinação simultânea de aminas biogênicas em vinhos e cafés solúveis

Abstract

Monitoring biogenic amines in food and beverage products is essential to ensure compliance with quality standards and consumer food safety. In this work, two analytical methods based on square-wave voltammetry (SWV) were developed, employing different electrodes and strategies to obtain first- and second-order multivariate data. In the first study, a zinc phthalocyanine–modified carbon paste electrode (CPE–ZnPc) was employed to generate first-order data. The successful modification of the optimized electrode was confirmed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. Under optimized conditions (borate buffer, pH 9.2; f = 50 Hz, a = 30 mV, and ΔEs = 6 mV), the proposed method enabled the simultaneous determination of tyramine and spermidine in wine and instant coffee samples, achieving low limits of detection of 48.6 nmol L⁻¹ for tyramine and 76.9 nmol L⁻¹ for spermidine. The method exhibited satisfactory accuracy, with recoveries ranging from 86.1% to 107.5%, and good reproducibility (RSD of 2.6%). Moreover, high selectivity was observed, as no significant interference affected the electrochemical quantification of the target analytes in either matrix. Consequently, no sample pretreatment was required, which contributes to the principles of green analytical chemistry. In the second study, a boron-doped diamond (BDD) electrode was used to acquire second-order voltammetric data through pulse amplitude variation. Under optimized SWV conditions (Britton–Robinson buffer, pH 9.0; f = 70 Hz, a = 20–70 mV, and ΔEs = 8 mV), a method was developed for the simultaneous quantification of putrescine, cadaverine, and histamine, allowing the resolution of highly overlapping voltammetric signals. For this purpose, calibration models based on Partial Least Squares Unfolded with Residual Bilinearization (U-PLS/RBL) and Resolution of Multivariate Curves with Alternating Least Squares (MCR-ALS) were constructed using individual standard solutions in the linear concentration range of 0.92 to 7.46 μmol L⁻¹, with limits of detection between 50 and 100 nmol L⁻¹. Overall, the combination of conventional electrodes with multiway calibration methods proved to be a promising strategy for the analysis of biogenic amine mixtures. Although application to real samples remains a subject for future investigation, the results demonstrate strong potential for the development of methodologies aimed at the simultaneous determination of biogenic amines in food matrices without prior sample preparation.