This work describes the development and validation of an offline solid-phase extraction with simultaneous cleanup capability, followed by liquid chromatography-(electrospray ionisation)-ion trap mass spectrometry, enabling the concurrent determination of 23 pharmaceuticals of diverse chemical nature, among the most consumed in Portugal, in wastewater samples. Several cleanup strategies, exploiting the physical and chemical properties of the analytes vs. interferences, alongside with the use of internal standards, were assayed in order to minimise the influence of matrix components in the ionisation efficiency of target analytes. After testing all combinations of adsorbents (normal-phase, ion exchange and mixed composition) and elution solvents, the best results were achieved with the mixed-anion exchange Oasis MAX cartridges. They provided recovery rates generally higher than 60%. The precision of the method ranged from 2% to 18% and 4% to 19% (except for diclofenac (22%) and simvastatin (26%)) for intra- and inter-day analysis, respectively. Method detection limits varied between 1 and 20 ng L(-1), while method quantification limits were <85 ng L(-1) (both excluding ibuprofen). This analytical method was applied to gather preliminary results on influents and effluents of two wastewater treatment plants (WWTPs) located in the urban region of Porto (Portugal). Typically, paracetamol, hydrochlorothiazide, furosemide, naproxen, ibuprofen, diclofenac and bezafibrate were detected in concentrations ranging from 1 to 20 μg L(-1), while gemfibrozil, simvastatin, ketoprofen, azithromycin, bisoprolol, lorazepam and paroxetine were quantified in levels below 1 μg L(-1). These WWTPs were given particular attention since they discharge their effluents into the Douro river, where water is extracted for the production of drinking water. Some sampling spots in this river were also analysed.

This work is based on the evaluation of the protein binding affinity, partition coefficients (with a biomimetic membrane) and surfactant properties of three pharmaceutically active ionic liquids based on the salicylate anion. Fluorescence spectroscopy was used for the evaluation of the binding of ionic liquids to human serum albumin and for the determination of critical micelle concentrations. Partition coefficients were determined using micelles of hexadecylphosphocholine and UV-Vis derivative spectroscopy. The results indicate that all the compounds bind strongly and spontaneously to human serum albumin and exhibit the ability to form micelles. The determined partition coefficients were up to 6 times higher than those of the starting materials, evidencing that the ionic liquid form has greater affinity for the lipid phase than the inorganic salt form of salicylate. Generally, the studied salicylate ionic liquids exhibit an interesting pharmaceutical profile presenting favorable properties regarding the incorporation of the compounds in antimicrobial pharmaceutical formulations. It was evidenced that the tested ionic liquids can exert direct effects on cell membranes as indicated by their surfactant properties and high ability to partition to hydrophobic environments.

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A new automated chemiluminescence method resorting to sequential injection analysis (SIA) was developed to rapidly determine biochemical oxygen demand (BOD). The assay is based on the redox reaction between quinone and Baker’s yeast in the presence of organic substances. The formed active oxygen species reacted with luminol, under the catalytic action of ferricyanide, and increased chemiluminescence signal. The automation of the assay ensured a precise control of the reaction conditions and enabled a reduction of more than 75-times in the reagents consumption and effluents production comparatively to BOD5. The sampling rate was widely improved with a flow rate of 8 cycles per hour. The method was applied to determine the BOD of ionic liquids (ILs) incorporating different chemical elements and deep eutectic solvents (DESs) combining choline chloride with varying hydrogen-bond donors. Differences in BOD and biodegradability were observed between tested compounds, with DESs showing, in general, higher BOD values and greater biodegradation than ILs. The results obtained in the developed bioassay demonstrated statistical correlation with the BOD5 method. Therefore, the developed methodology is a simple, economic and high-throughput alternative screening bioassay to the conventional method, with the potential to preliminarily assess the potential biodegradability of chemicals in the environment.