Determinação de HPAS em cachaça e açúcar utilizando membranas de náilon, espectroscopia de fluorescência e PARAFAC

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are formed from the incomplete combustion of organic matter, being classified as persistent organic pollutants, with some recognized as carcinogenic. In the context of sugarcane, the practice of burning for agricultural management or energy production can generate PAHs, which contaminate derived products such as cachaça and sugar. These products are widely consumed in Brazil, highlighting the importance of monitoring PAHs in these matrices. Chromatography is the reference technique for determining these contaminants; however, it is costly and requires a significant amount of analysis time. In this study, alternative approaches based on fluorescence spectroscopy using nylon membranes combined with second-order calibration (PARAFAC) were evaluated for the determination of PAHs. Two preconcentration systems were employed: (i) positive-pressure filtration using a filter holder, applied to cachaça samples, and (ii) rotating-disk sorptive extraction (RDSE), applied to sugar samples. The PAHs studied were benzo[a]pyrene, benzo[a]anthracene, benzo[b]fluoranthene, benzo[g,h,i]perylene, and dibenzo[a,h]anthracene. For sugar samples, the RDSE system exhibited problems caused by the presence of sucrose, which hindered the achievement of satisfactory results. In addition to the high viscosity of sugar solutions, sucrose impregnated the membrane, leading to fluorescence suppression, thereby evidencing a strong matrix effect. Reflectance and fluorescence spectra of sugar samples were presented in this study to demonstrate this effect. The filtration system for cachaça proved quantitative and effective for detecting PAHs in the range of 24 to 225 ng L⁻¹. The method yielded apparent recoveries between 91% and 105%. RMSEP values ranged from 11 to 17 ng L⁻¹, while limits of detection were between 16 and 27 ng L⁻¹, demonstrating good sensitivity associated with low method errors.