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Electrical asymmetric-flow field-flow fractionation (EAF4) is a new and interesting analytical technique recently proposed for the characterization of metallic nanoparticles (NPs). It has the potential to simultaneously provide relevant information about size and electrical parameters, such as electrophoretic mobility (μ) and zeta-potential (ζ), of individual NP populations in an online instrumental setup with an array of detectors. However, several chemical and instrumental conditions involved in this technique are definitely influential, and only few applications have been proposed until now. In the present work, an EAF4 system has been used with different detectors, ultraviolet-visible (UV-vis), multi-angle light scattering (MALS), and inductively coupled plasma with triple quadrupole mass spectrometry (ICP-TQ-MS) for the characterization of gold, silver, and platinum NPs with both citrate and phosphate coatings. The behavior of NPs has been studied in terms of retention time and signal intensity under both positive and negative current with results depending on the coating. Carrier composition, particularly ionic strength, was found to be critical to achieve satisfactory recoveries and a reliable measurement of electrical parameters. Dynamic light scattering (DLS) has been used as a comparative technique for these parameters. The NovaChem surfactant mix (0.01%) showed a quantitative recovery (93 ± 1%) of the membrane, but the carrier had to be modified by increasing the ionic strength with 200 μM of Na

A rapid and reliable method based on magnetic solid-phase extraction (MSPE) and ultra-high performance liquid chromatography (UHPLC-FLD) analysis was developed and validated for the quantitative determination of seven polycyclic aromatic hydrocarbons (PAHs) in water samples. Hybrid composites made up of magnetic nanoparticles (MNPs) and carbon nanotubes (CNTs) were tested as adsorbent materials. The main factors influencing the extraction yields were optimized, namely the amount and type of adsorbent in the adsorption, and the solvent, the type of energy and the time in the desorption step. The selected composite was made up of Fe3O4 and multiwalled (MW)-CNTs. The desorption was carried out with sonication probe and tetrahydrofuran (THF); this solvent makes the method directly compatible with the chromatographic mobile phase and it reduces the analysis time. Under the optimized conditions, the LODs and LOQs achieved were in the range of 0.025–0.73 and 0.04–2.4 ng mL−1, respectively. The calibration curves were linear (R 2 ≥ 0.9936) over the concentration ranges from 1 to 500 ng mL−1. The recoveries of PAHs were from 76.4 ± 1.7 up to 106.5 ± 3.5%. The method was applied to synthetic and real (tap, dam, river and mineral) water samples with different characteristics to evaluate the performance under real conditions.