Nejvíce citovaný článek - PubMed ID 12349984
Label-free determination of picogram quantities of DNA by stripping voltammetry with solid copper amalgam or mercury electrodes in the presence of copper
This year we celebrate seventy years since the establishment of the Institute of Biophysics of the Czechoslovak Academy of Sciences (IBP) (founded on January 1, 1955). If we look into the biography of Professor Emil Paleček (born on October 3, 1930), one of the most world-recognized personalities associated with the Institute and one of the most cited Czech scientists, known as the founder of nucleic acids electrochemistry, we are drawn to the same year, i.e. 1955, as the year in which Emil Paleček finished his studies in biochemistry and joined the IBP, where he worked with admirable vitality, enthusiasm and dedication until his death (October 30, 2018). In the context of celebration of founding of the Institute, we would like to commemorate in this article a personality who significantly influenced the history of the Institute alongside the important discoveries and research directions that defined his extremely successful career. We prefer this form, which is a sort of a mini-review of the most important results of the laboratory obtained under EP's leadership over 63 years, presented in mutual context and natural relations. For his life's work, Professor Paleček received many prestigious awards, with the Czech Head Award in 2014 and the Neuron Foundation Award in 2017 being the most distinguished.
- Klíčová slova
- Electrochemistry, Glycans, Modification, Nucleic acids, Proteins, Structure,
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Toxic metal contamination of the environment is a global issue. In this paper, we present a low-cost and rapid production of amalgam electrodes used for determination of Cd(II) and Pb(II) in environmental samples (soils and wastewaters) by on-site analysis using difference pulse voltammetry. Changes in the electrochemical signals were recorded with a miniaturized potentiostat (width: 80 mm, depth: 54 mm, height: 23 mm) and a portable computer. The limit of detection (LOD) was calculated for the geometric surface of the working electrode 15 mm² that can be varied as required for analysis. The LODs were 80 ng·mL-1 for Cd(II) and 50 ng·mL-1 for Pb(II), relative standard deviation, RSD ≤ 8% (n = 3). The area of interest (Dolni Rozinka, Czech Republic) was selected because there is a deposit of uranium ore and extreme anthropogenic activity. Environmental samples were taken directly on-site and immediately analysed. Duration of a single analysis was approximately two minutes. The average concentrations of Cd(II) and Pb(II) in this area were below the global average. The obtained values were verified (correlated) by standard electrochemical methods based on hanging drop electrodes and were in good agreement. The advantages of this method are its cost and time effectivity (approximately two minutes per one sample) with direct analysis of turbid samples (soil leach) in a 2 M HNO₃ environment. This type of sample cannot be analyzed using the classical analytical methods without pretreatment.
- Klíčová slova
- amalgam electrodes, electrochemistry, heavy metals, soil, turbid sample,
- Publikační typ
- časopisecké články MeSH
Using a paraffin impregnated graphite electrode (PIGE) and mercury-modifiedpyrolytic graphite electrode with basal orientation (Hg-PGEb) copper(II) and Cu(II)-DNApurine base solutions have been studied by cyclic (CV) and linear sweep voltammetry(LSV) in connection with elimination voltammetry with linear scan (EVLS). In chlorideand bromide solutions (pH 6), the redox process of Cu(II) proceeded on PIGE with twocathodic and two anodic potentially separated signals. According to the eliminationfunction E4, the first cathodic peak corresponds to the reduction Cu(II) e⁻ → Cu(I) withthe possibility of fast disproportionation 2Cu(I) → Cu(II) Cu(0). The E4 of the secondcathodic peak signalized an electrode process controlled by a surface reaction. Theelectrode system of Cu(II) on Hg-PGEb in borate buffer (pH 9.2) was characterized by onecathodic and one anodic peak. Anodic stripping voltammetry (ASV) on PIGE and cathodicstripping voltammetry (CSV) on Hg-PGEb were carried out at potentials where thereduction of copper ions took place and Cu(I)-purine complexes were formed. By usingASV and CSV in combination with EVLS, the sensitivity of Cu(I)-purine complexdetection was enhanced relative to either ASV or CSV alone, resulting in higher peakcurrents of more than one order of magnitude. The statistical treatment of CE data wasused to determine the reproducibility of measurements. Our results show that EVLS inconnection with the stripping procedure is useful for both qualitative and quantitativemicroanalysis of purine derivatives and can also reveal details of studied electrodeprocesses.
