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This study involved the development, validation and application of a three-phase hollow-fiber liquid-phase microextraction (HF-LPME) and liquid chromatography with diode array detection (LC-DAD) method for the simultaneous determination of the proton pump inhibitor (PPI) drugs omeprazole, pantoprazole and lansoprazole in human plasma. The evaluation of the HF-LPME parameters was crucial for the determination of the drugs and the conditions selected were: 1-octanol as solvent; phosphate buffer at pH 5 as donor phase; borate buffer at pH 10 as acceptor phase; extraction time of 15 min; stirring at 750 rpm and NaCl was added at 5% (w/v). Validation of the method according to US-FDA recommendations showed a good linear range (0.2-2.0 μg/mL) for all analytes, with a determination coefficient >0.9910. Precision was evaluated using intra- and inter-day assays, which showed relative standard deviations (RSD), <15% for all concentrations, with a limit of quantification (LOQ) of 0.2 μg/mL. Accuracy was also assessed at these concentration levels and was in the range from 80 to 130%. Finally, the sensitive, selective and reproducible HF-LPME/LC-DAD developed method was successfully applied to human plasma samples from patients undergoing therapy with the PPI drugs.

An electrochemical sensor for the pesticide Pirimicarb (PMC) has been developed. A screen-printed electrode (SPCE) was used and modified with the conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) and gold nanoparticles (AuNPs) to enhance electrochemical proprieties. Electrode characterizations were performed using scattering electron microscopy (SEM) and cyclic voltammetry (CV). With the SPCE/PEDOT:PSS/AuNPs modified electrode, a new peak at 1.0 V appeared in the presence of PMC related to the PMC oxidation. To elucidate the mechanism of PMC oxidation, Gas Chromatography-Mass Spectrometry (GC-MS), where two major peaks were identified, evidencing that the device can both detect and degrade PMC by an electro-oxidation process. Exploring this peak signal, it was possible the sensor development, performing detection from 93.81–750 µmol L−1, limits of quantification (LOQ) and detection (LOD) of 93.91 µmol L−1 and 28.34 µmol L−1, respectively. Thus, it was possible to study and optimization of PMC degradation, moreover, to perform detection at low concentrations and with good selectivity against different interferents using a low-cost printed electrode based on graphite modified with conductive polymer and AuNPs.

Effective liquid-liquid fractionation methods of the heavy bio-oil have been pursued to improve the key biomass functionalities. Here, fast-pyrolysis bio-oil derived from eucalypt wood was fractionated in cold water to separate insoluble- and water-soluble fractions. We focus on the water-soluble fraction, a promising renewable source of chemicals with potential antimicrobial approaches. Fast-pyrolysis bio-oil was fractionated in three oil-to-water ratios, 1:100, 1:50, and 1:35, separating the pyrolytic lignin and producing water-soluble fractions as byproducts. The water-soluble fractions were analytically investigated through physicochemical properties, chemical composition by chromatography, phenolic content, antioxidant activity, antimicrobial activity, and their storage stability. Higher water content in the pyrolytic lignin separation resulted in higher yield and solids concentration in the water-soluble fractions, with the presence of high value-added chemicals, such as catechol, vanillin, and levoglucosan. Levoglucosan was the dominant chemical identified in the water-soluble fractions, notably for the 1:50 oil-to-water ratio. These remarkable chemicals and a high phenolic content contribute to both high antioxidant and antimicrobial activities. Despite the low concentration, all water-soluble fractions exhibited intense inhibition of Trametes versicolor and Gloeophyllum trabeum fungi. The fraction 1:50 completely inhibited the fungal activity. Both 1:100 and 1:50 fractions showed antibacterial activity for Escherichia coli and Staphylococcus aureus. Regardless of the oil-to-water ratio, water-soluble fractions exhibited a relative storage chemical stability under accelerated aging conditions for 43 days. Therefore, water-soluble fractions of fast-pyrolysis bio-oil derived from a simple method to separate pyrolytic lignin are functional materials with remarkable properties and, hence, upgrading bio-oil based on their functionalities.

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