Electrochemistry of catalase at a liquid|liquid micro-interface array

The electrochemistry of catalase (CAT) was investigated at the interface between two immiscible elec-trolyte solutions (ITIES) as a step towards its detection. Electrochemistry at the ITIES offers advantages such as the non-redox detection of biomolecules. The electrochemical behaviour of CAT at the ITIES, in a micro-interface array format, displayed a distinct cyclic voltammogram when the aqueous phase pH was lower than the isoelectric point (pI) of CAT. No voltammetric response was observed when the aque-ous phase pH > pI of CAT, indicating that neutral or negatively charged CAT has no capability to facilitate anion transfer from the organic phase. Adsorptive stripping voltammetry (AdSV) was assessed for detec-tion of low concentrations at the mITIES array. Application of a positive preconcentration potential for a fixed time enabled interfacial accumulation of CAT as a complex; subsequently, a voltammetric scan to lower potentials desorbed the complex, providing the electroanalytical signal. Assessment of sample matrix effects by examining the electrochemistry of CAT in artificial serum indicated that detection in pH-adjusted samples is feasible. Together, these results demonstrate that CAT is electroactive at the liq-uid-liquid interface and this may be useful as a strategy to detect and characterize the enzyme in a label-free manner. (c) 2020 Elsevier B.V. All rights reserved.

Automated summary

The electrochemistry of catalase (CAT) was investigated at the liquid-liquid interface, demonstrating its electroactive nature under specific conditions. Analysis of CAT's electrochemical behavior in a micro-interface array format allows for its detection and characterization at the interface.