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Your search keyword '"Giokas, Dimosthenis L."' showing total 348 results
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348 results on '"Giokas, Dimosthenis L."'

7. A Revisit to Effervescence-Assisted Microextraction of Non-Polar Organic Compounds Using Hydrophobic Magnetic Nanoparticles—Application to the Determination of UV Filters in Natural Waters.

Author

Toti, Efthymia, Gouma, Vasiliki, Karagianni, Vasiliki I., and Giokas, Dimosthenis L.

Subjects
MAGNETIC materials, WATER filters, ORGANIC compounds, WATER use, WATER sampling
Abstract

In this work, we revisited the method of effervescence-assisted microextraction, aiming to assess the effects of the process of effervescence on the extraction efficiency of organic compounds. We used a magnetic nano-sorbent material composed of stearic acid-coated cobalt-ferrite magnetic nanoparticles as an adsorbent and dispersed it in water using 12 combinations of acid and base mixtures at two different mass ratios. The solution pH, the ionic strength, and the duration of effervescence were calculated and correlated to the extraction efficiency of nonpolar UV filters from aqueous samples as model organic compounds. Our findings provide a general perspective into the influence of the process of effervescence on extraction efficiency. Based on these findings, we developed and optimized a new analytical method for extracting UV filters from water samples using HPLC-UV as a detector. Under the optimum experimental conditions (0.2 g fumaric acid/0.1 g Na2CO3, 50 mg of magnetic nanoparticles and methanol as an elution solvent assisted by vortex agitation for 5 min) the method was found to afford good linearity in the calibration curves expanding by two orders of magnitude, satisfactory reproducibility and repeatability (1.8–11.1%), and high recoveries (78.4–127.1%). This research provides a new perspective on the influence of the process of effervescence on the extraction efficiency of nonpolar organic compounds and introduces a new method for extracting UV filters from aqueous media. [ABSTRACT FROM AUTHOR]

Published
2024
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14. From Simple Packaging Materials to Smart Sensors: Sunlight Exposure Sensing in Bubble Wraps Incorporating a Layered Metal Selenide Photocatalyst.

Author

Karagianni, Vasiliki I., Georgiadis, Andronikos, Lykos, Christos, Vlessidis, Athanasios G., Konstantinou, Ioannis, Manos, Manolis J., and Giokas, Dimosthenis L.

Subjects
PACKAGING materials, INTELLIGENT sensors, RGB color model, SELENIDES, SMART materials, SUNSHINE
Abstract

This work demonstrates that the packaging material commonly called "bubble wraps" (Aeroplast) can be leveraged to serve as a probe to visible sunlight exposure. This probe relies on a newly developed layered metal selenide photocatalyst with the general formula (DMAH)2xMnxSn3–xSe6 (DMSe‐1) (x = 1.3–1.7; DMAH+ = dimethylammonium), featuring a narrow bandgap of 0.76 eV, in addition to an indicator dye and a reducing agent. The photochemically sensitive probe is introduced into the air‐filled compartments of bubble wraps and undergoes photocatalytic degradation, resulting in a chromatic response to sunlight exposure. The probe's sensitivity to variable irradiation doses can be adjusted by varying the amount of the photocatalyst. The color intensity correlates with the absorbed irradiation dose, allowing for qualitative assessment by the naked eye or quantitative measurement using the RGB color system. The results obtained from the new probe agree with those obtained from standard sunlight pyranometers (r = 0.98), with an average error of <15%. This suggests that beyond their use as protective coatings, bubble wraps can be successfully repurposed as visible light sensors. Furthermore, this study describes the initial use of metal chalcogenides as visible light probes, potentially paving the way for the development of innovative light‐sensitive materials. [ABSTRACT FROM AUTHOR]

Published
2024
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