Cyclic voltammetry (CV) is a type of electrochemical measurement which is applied in the Q-Module as a quality control step to determine the redox potential of Coenzyme Q in the specific experimental conditions used. In cyclic voltammetry, the Q-Sensor with the three-electrode system is used to obtain information about the analyte (CoQ) by measuring the current (I) as the electric potential (V) between two of the electrodes is varied. In CV the electric potential between the glassy carbon (GC) and the Ag/AgCl reference electrode changes linearly versus time in cyclical phases, while the current is detected between GC and platinum electrode (Pt). The detected current is plotted versus the applied voltage to obtain the typical cyclic voltammogram trace (Figure 1). The presence of substances that are oxidized/reduced will result in current between GC and Pt, which can be seen as characteristic peaks in the voltammogram at a defined potential. The oxidation or the reduction peak potential values are used to set the GC (integrated into the Q-Sensor) for a separate experiment to measure the Q redox state of a biological sample. The oxidation and reduction peak potentials can be influenced by 1) the respiration medium, 2) type of CoQ, 3) polarization window, 4) scan speed, 5) number of cycles, 6) concentration of the analyte (CoQ),and 7) initial polarization voltage. For further information, see: MiPNet24.12 NextGen-O2k: Q-Module.
Figure 1. Cyclic voltammogram of Coenzyme Q2 measured with the Q-Module. Measurements were carried out in non-stirred MiR05-Kit medium, at 37 °C using the NextGen-O2k. Initial potential: +30 mV, polarization window: between -500 mV and +500 mV, scanning speed: 100 mV/s, gain: 1; 30 µM Q2 was used for each test. The oxidation peak potential shows the maximum rate of quinol oxidation and the reduction peak potential is the point of maximum rate of quinone reduction.
Cyclic voltammetry is part of the Q-Module and the NextGen-O2k project
In the NextGen-O2k project we are working on developing the Q-Module for the new series of our O2k-FluoRespirometer, the NextGen-O2k. The Q-Module allows us to monitor the Q redox state of the Q-junction using the specific Q-Stoppers with the integrated three-electrode system and the modified electronics inside the O2k housing.
Communicated by Komlodi T, Cardoso LHD 2020-07-28
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Mitochondrial pathways, respiratory Complexes, and Q
NextGen-O2k and Q-Module