In this paper, we proposed a procedure for the determination of Fe(III) and total Fe(II)+Fe(III) in wine samples employing newly synthesized Fe(II) ion imprinted polymer (Fe(II)-IIP) as a sorbent incorporated in dispersive solid phase extraction. Cross-linked precipitation copolymerization using 4-vinylpyridine (functional monomer), trimethylolpropane trimethacrylate (cross-linking agent) and 2,2′-bipyridyl as a specific for Fe(II) ligand was used for the synthesis of Fe(II)-IIP. The optimization experiments showed quantitative sorption of both Fe(II) and Fe(III) on the surface of Fe(II)-IIP at pH 7, however selective sorption of only Fe(II) could be achieved in the presence of fluoride ions as a masking agent for Fe(III). The Langmuir adsorption isotherm best described the adsorption of Fe(II) on the surface of the sorbent on the at least two kinds of binding sites with higher and lower affinities as defined by Scatchard plot. The analytical procedure developed allows the determination of iron(III) and total Fe(II)+Fe(III) in wine samples, with limits of quantification 0.1 mg L-1. The relative standard deviation varied in the range 3-7% for Fe content 0.1-10 mg L-1 .
The rising interest in harmful cyanoprokaryote blooms promotes an increase of phycological and ecological research on potentially toxic species and their hazardous substances. The present study aimed to identify the main microcystin (MC) producers and their contribution to the phytoplankton of shallow waterbodies in Bulgaria, applying different methods. The sampling was performed in August 2019 in nine lakes and reservoirs, two of which (reservoirs Kriva Reka and Izvornik 2) were studied for the first time. The high contribution of cyanoprokaryotes to the total species composition and phytoplankton abundance was proved by light microscopic (LM) observations and HPLC analysis of marker pigments. The LM identification of potential MC-producers was supported by PCR amplification of mcyE and mcyB genes. The MCs amounts, detected by HPLC-DAD, varied by sites with a range from undetectable concentrations to 0.46 µg L−1 with only one recorded variant, namely MC-LR. It was found only in the reservoirs Mandra and Durankulak, while toxigenic MC-strains were obtained by PCR from five more waterbodies. Both LM and PCR demonstrated that the MC-producers were Microcystis aeruginosa and M. wesenbergii, despite their occurrence in low amounts (<0.5–5% of the total biomass) when filamentous cyanoprokaryotes dominated.
This study is focused on the synthesis of chromate anion imprinted sorbent supported on silica gel for nonchromatographic Cr speciation in surface waters. The preparation procedure is based on grafting of 3-methyl-1trimethoxysilylpropylimidazolium, preliminarily coordinated to CrO 2− 4 as a template ion, onto the surface of silica gel.Sorption and desorption characteristics of surface-imprinted sorbent toward Cr(III) and Cr(VI) were examined by batch solid-phase extraction. An excellent separation of Cr(VI), selectively retained on the sorbent, from Cr(III) remained in the solution, was achieved at pH 2-3 for 20 min. A freshly prepared mixture of ascorbic acid and nitric acid was selected as the most efficient eluent for quantitative desorption of the retained Cr(VI). An analytical procedure for Cr speciation in surface waters was developed and validated through analysis of certified reference materials. Detection limits achieved and relative standard deviations for typical concentration levels of Cr(VI) in surface waters matched the requirements of analytical procedures used in monitoring programs.
The effect of template species -Fe(II) complexes with 4-(2-pyridylazo)resorcinol or 2,2 0 -bipyridine as well as the functional monomers: acidic (methacrylic acid) and neutral (hydroxyethyl methacrylate) on the extraction efficiency and applicability of Fe(II) ion-imprinted polymers for iron speciation in surface waters is presented in this study. The polymers were synthesized by precipitation copolymerization of functional monomer, trimethylolpropane trimethacrylate (crosslinking agent) and 2,2 0 -azo-bis-isobutyronitrile (initiator) in the presence of template and characterized by elemental microanalysis, SEM and Brunauer-Emmett-Teller analyses. Extraction efficiency was examined by batch solid-phase extraction. The equilibrium experimental data of adsorption processes with different synthesized sorbents were fitted by both Langmuir and Freundlich isotherms and are discussed from the viewpoint of possible bond formation between monomer and template species and the stability of the prepolymerization complex. Pseudo-first-order and pseudo-second-order kinetic models were tested to elucidate the possible controlling mechanism of the sorption process for different sorbents. Under the optimum conditions pH 7 and equilibrium time of 30 min the highest extraction efficiency and selectivity toward Fe(II) was achieved for Fe(II) ion-imprinted polymer containing methacrylic acid and Fe(II)-4-(2-pyridylazo)resorcinol complex as a template. The analytical procedure for Fe speciation was developed and validated with this sorbent.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.