Showing papers by "Samo B. Hočevar published in 2019"

The in vivo effects of silver nanoparticles on terrestrial isopods, Porcellio scaber, depend on a dynamic interplay between shape, size and nanoparticle dissolution properties

Abstract: The present work aims to study the effects that acute exposure to low concentrations of silver nanoparticles (AgNPs) cause in digestive glands of terrestrial isopods (Porcellio scaber). The experiments were designed to integrate different analytical techniques, such as transmission electron microscopy, atomic absorption spectroscopy, proton induced X-ray emission, and Fourier transform IR imaging (FTIRI), in order to gain a comprehensive insight into the process from the AgNPs’ synthesis to their interaction with biological tissues in vivo. To this aim, terrestrial isopods were fed with AgNPs having different shapes, sizes, and concentrations. For all the tested conditions, no toxicity at the whole organism level was observed after 14 days of exposure. However, FTIRI showed that AgNPs caused detectable local changes in proteins, lipids, nucleic acids and carbohydrates at the tissue level, to an extent dependent on the interplay of the AgNPs’ properties: shape, size, concentration and dissolution of ions from them.

A novel bismuth imidazolate-based sensor for detection of trace lead(II)

Abstract: Abstarct A new type of bismuth electrode (BiImE) for anodic stripping voltammetric detection of trace Pb(II), which is based on a bismuth imidazolate (BiIm) sensing coating, is presented. A simple preparation protocol was adopted via drop-casting a rapidly drying methanol suspension of amorphous BiIm, serving as a source of bismuth ions, onto a supporting glassy carbon electrode. The BiIm sensing material was characterized and several key parameters influencing the preparation and performance of BiImE were investigated. The BiImE revealed good linear response in the two examined concentration ranges of 10–100 μg L−1 and 1–10 μg L−1 with r2 of 0.998 and 0.995, respectively, a low limit of detection (3σ) of 0.1 μg L−1 Pb(II) associated with 240 s accumulation, and a favorable repeatability with RSD of 3.8%. Even after scanning the potential toward more positive values than the re-oxidation potential of bismuth, the BiImE could be reused several times without any significant loss of performance, hence making it superior compared to its ex situ prepared counterparts while exhibiting advantages of the in situ prepared analogues. The applicability of BiImE was demonstrated through measuring Pb(II) in a real tap water sample. Preliminary experiments also proved its suitability for simultaneous measurement of trace Pb(II) and Cd(II).