Parabenos em efluente hospitalar: quantificação e identificação de metabólitos e subprodutos de oxidação avançada

Abstract

In this study, it was developed an analytical methodology for the quantification of parabens (PBs) in hospital effluent (University Hospital of Santa Maria - HUSM), by using solid phase extraction (SPE) followed by liquid chromatography coupled to diode array detector (HPLC-DAD). The main SPE variables were investigated by multivariate planning and optimized for the extraction/recovery of methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), butylparaben (BuP) and benzylparaben (BeP). The recovery rates varied from 75% upto 109% (± 1,0% upto 13,0%) for aqueous solution, and from 72% upto 106% (± 7,0% upto 15,5%) for hospital effluent. MeP e PrP showed the highest concentrations related to the other PBs on the sampling points HUSM General‟ (HG) e Receptor Water Course‟ (CR). The BuP concentration laid below the limit of detection (LD). Liquid Chromatography coupled to a sequential mass spectrometer provided with electrospray ionization (LC-ESI-MS/MS) was used for the identification of the metabolite, p-hydroxybenzoic acid, in hospital effluent. Photolysis and Heterogeneous photocatalysis were applied to the degradation of PBs and the variables were investigated with multivariate planning. A stirring tank reactor provide with a thermostatic jacket was used for the advance oxidation processes. Adsorption bars with titan dioxide (TiO2) supported on polydimethylsiloxane (PDMS) and polyurethane (PU) polymers were used and the efficiency was compared to the catalyst in suspension. Kinetic studies of the oxidation reactions were conducted and a total of eleven degradation products were identified by LC-ESI-MS/MS. A preliminary risk evaluation revealed that all the PBs showed a low environmental risk, MEC/PNEC < 1.