engleski

Tensammetry of Proteins and Polysaccharides on Mercury Electrode under Conditions of Catalytic Activity

Proteins and polysaccharides adsorb ubiquitously on the mercury electrodes. Depending on the structure, they produce catalytic hydrogen evolution reaction (CHER) peak in a buffer solution using voltammetric and chronopotentiometric stripping method. Here we show that the voltammetric appearance of CHER peak at very negative potentials, ~ -1.8 V in the protein and polysaccharide solution, is accompanied by a capacitive current minimum in alternate current (AC) out-of-phase voltammetry. The observed “tensammetric minimum” highly depended on buffer concentration, ionic strength, pH, catalyst concentration and time of accumulation. One of the possible reason for its appearance could be strong adsorption of the positively charged species such as hydrogen ions at the negatively charged mercury electrode. Moreover, tensammetric minimum proved to be sensitive toward catalytically active protein or polysaccharide when present in the mixture with catalytically inactive molecule.

Catalytic hydrogen evolution reaction ; tensammetry ; biomacromolecules ; mercury electrode

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