Microextração líquido-líquido dispersiva na determinação de bisfenóis (A, S, F, AF) e de benzofenona em amostras aquosas reais e complexas: desenho experimental e otimização de processos

Abstract

The Dispersive Liquid-liquid Microextraction (DLLME) is a technique for extraction and concentration of target compounds applied to aqueous matrices of high complexity, such as sewage, industrial effluents and environmental samples. Bisphenol and benzophenone are widely applied in the manufacture of products in different industrial sectors and have been increasingly detected in different environmental and biological matrices. These compounds are associated to a variety of physiological dysfunctions and health impacts. Therefore, proper detection and quantification of bisphenols and benzophenone in aqueous matrices are necessary. The objective of this study was to find the best condition for a joint extraction/recovery process of Bisphenol A (BPA), Bisphenol S (BPS), Bisphenol F (BPF), Bisphenol AF (BPAF) and Benzophenone (BZP) by Dispersive Liquid-liquid Microextraction (DLLME), using the statistical approach Design of Experiments (DoE) for process optimization. In the present study, optimised DLLME was used for extraction/recovery of these compounds in complex aqueous matrices. Analytes were identified and quantified using a Xevo TQD®, Quadrupole (UPLC-MS/MS Waters) equipment. The selection of variables and conditions considered relevant for optimization of DLLME was done with the construction of two successive matrices of Plackett-Burman Design (PB) followed by a Central Composite Rotatable Design (CCRD) for a joint optimization. After the optimization, the best extraction condition was applied to five real samples (raw and treated wastewaters and surface waters) obtained in Rio de Janeiro city, Brazil. The recovery efficiencies ranged from 83 to 121% for BPA, 76 to 91% for BPS, 89 to 98% for BPF, 60% to 92% for BPAF and 81 to 99% for BZP. The concentrations of target analytes found in real samples were: BPA (0.054-150 µg L-1), BPS (0.329-18.2 µg L-1), BPF (0.048-0.091 µg L-1), BPAF (0.005-0.027 µg L-1), BZP (0.402-0.923 µg L-1). The association of DLLME with the UPLC-MS/MS met the validation requirements adopted and enabled high analytical standards. Additional advantages of applying this extraction technique instead of SPE commonly used is the low analytical cost per analysis ($0.10 USD) and low sample volume required, making it possible to process a larger number of samples quickly, with simplicity and efficiency, besides being environmentally friend.