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An Enzymatic Biosensor with Amperometric Detection in a Flow Injection Analysis for the Determination of L-lactic Acid: Development and Application
Tvorynska, Sofiia ; Barek, J. ; Josypčuk, Bohdan
An amperometric biosensor consisting of an enzymatic mini-reactor (lactate oxidase covalently\nattached to −NH2 functionalized mesoporous silica powder SBA−15 using glutaraldehyde) and\na silver amalgam-based screen-printed electrode acting as a transducer was developed for the\ndetermination of L-lactic acid (LA) in FIA. The detection potential of −0.9 V vs. Ag pseudoreference\nelectrode was applied for cathodic detection of enzymatically consumed oxygen.\nUnder the optimized conditions, the constructed biosensor enabled selective determination of\nLA with a micromolar limit of detection. Importantly, the proposed biosensor represented\nexcellent operational stability after ≥350 measurements. Finally, it was successfully applied to\nreal sample analysis.
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Preparation, Testing and Application of Amalgam Screen-Printed Electrodes
Josypčuk, Bohdan ; Langmaier, Jan ; Tvorynska, Sofiia
Silver amalgam screen-printed electrodes (AgA-SPEs) were designed, prepared, and tested for\nthe first time as perspective representatives among SPEs for measuring at high negative\npotentials. The precise coulometric preparation procedure for mercury deposition at the\nworking electrode surface of the commercial silver-SPE was developed. An optimal\nelectrolyzer construction for the mercury deposition, electrolyte composition, and electrolysis\nconditions were proposed. The maximum value of hydrogen overvoltage (-1979 ± 4 mV) was\nfound on AgA-SPE with 50% (w/w) of Hg content in 0.1 mol L-1 NaOH, which is more negative\nthan with the original silver-SPE for 387 mV (-1592 ± 12 mV).
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Amalgam Electrodes Pretreatment and Electrochemical Analysis of DNA
Daňhel, Aleš ; Fojta, Miroslav
Mercury meniscus silver solid amalgam electode (m-AgSAE) represents the most suitable and perspective alternative to mercury electrodes which excel in sensitivity to biopolymers and their structural changes. This work briefly summarizes factors influencing electrochemical analysis of DNA at mercury and amalgam electrodes and it is mainly devoted to development of suitable pretreatment procedure, which could securte repeatable and reliable measurements of DNA at m-AgSAes. The results are essential for further utilization of amalgam electrodes in developement of biosensors, since DNA samples are very strongly adsorbed at the electrodes, and none pretreatment procedure was found to be successful in their complete desorption.
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Electrochemical Deposition of Silver Amalgam Particles on Pyrolitic Graphite Electrode
Šebest, Peter ; Havranová-Vidláková, Pavlína ; Ligmajer, Filip ; Fojta, Miroslav ; Daňhel, Aleš
Silver solid amalgam represents suitable alternative electrode material to metallic mercury, Controlled electrodeposition of variable silver amalgam particles (AgAP) on the surface of pyrolitic graphite electrode from an electrolyte containing Agt It and Hg(II) ions is reported as a novel method suitable lot preparation of perspective supporting materials Scanning electron microscopy including energy-disperse X-ray spectrometer and image processing software were used for analysis of composition and morphology of AgAP on POE A model electrochemically reducible 4-niirophenol was used to test a potential applicability of AgAp-PGE in electroanalytical methods.
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Preparation and Characterization of Silver Amalgam Particles on Gold Electrode Surface
Havranová-Vidláková, Pavlína ; Šebest, Peter ; Ligmajer, Filip ; Fojta, Miroslav ; Daňhel, Aleš
This work is focused on the preparation of silver amalgam particles by its direct electrodeposition on gold surfaces using double pulse chronoamperometry from solution containing soluble Ag+ and Hg2+ ionts. During the electrodepositions of silver amalgam particles, different: i) parameters of chronoamperometry, ii) Ag/Hg ratio in solution and iii) gold electrodes were studied. All the prepared amalgam particles were characterized by scanning electron microscope with energy dispersive X-ray spectroscopy and electrochemical methods. Voltammetric application of the gold electrodes decorated by sliver amalgam particles was confirmed by analysis of model organic nitrocompound using cyclic voltammetry.
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