292
2. Mount all the electrodes on the cell. Manually polish the surface of the working electrode with alumina (Al 2 O 3 ) water suspension on DP-Nap (Struers) prior to recording each cyclic
voltammogram.
3. Bubble the solution by argon or nitrogen to remove oxygen
before each measurement.
4. Record the cyclic voltammogram of the blank solution and then
transfer the solution of the target compound to the cell.
5. Record cyclic voltammograms at different scan rates and different values of concentration.
6. Analyze the shape of cyclic voltammograms in Origin or Excel
software and use values of I p and E p to determine the electrode
processes (see Notes 1 and 2).
7. Figure 2 shows that E p of quercetin-2HP-β-CD complex in
solution at different pH values differs, signifying that protons
participate in the oxidation (see Note 3). The dependence of
E p /pH indicates the ratio between the number of participating
protons and electrons [21, 23].
1. Prepare the solutions of the drug and of the CD-drug complex
in anoxic conditions, by bubbling argon in all vials and solvent
used for their preparation.
2. Transfer the blank solution to the spectroelectrochemical cell
and record the blank, against which absorption spectra will be
recorded. Remove the blank solution from the cell.
3. Transfer the target solution to the spectroelectrochemical cell
by a syringe under inert atmosphere.
4. Set up the potentiostat to perform cyclic voltammetry experiments with a scan rate of 5 mV/s, or to perform chronoamperometry for 300-s time.
5. In order to monitor the spectral changes during the electron
transfer, set the spectrophotometer for kinetics measurement to
record spectra every 3 s, sufficient to recognize the redox intermediates and products.
6. Start simultaneously the application of potential by the potentiostat and the monitoring of absorption spectra by the spectrophotometer. Plot register data in Origin or Excel software
(Fig. 3).
7. Clean first the surface of the platinum working electrode
mounted on the cell by washing it with solvents (water, ethanol,
acetone, acetonitrile) and afterwards by electrochemical cleaning (see Note 4).
3.2 The Generation
of Oxidation Products
Electrochemically
3.2.1 In Situ UV–Vis
Spectroelectrochemistry
Romana Sokolová and Ilaria Degano
2. Mount all the electrodes on the cell. Manually polish the surface of the working electrode with alumina (Al 2 O 3 ) water suspension on DP-Nap (Struers) prior to recording each cyclic
voltammogram.
3. Bubble the solution by argon or nitrogen to remove oxygen
before each measurement.
4. Record the cyclic voltammogram of the blank solution and then
transfer the solution of the target compound to the cell.
5. Record cyclic voltammograms at different scan rates and different values of concentration.
6. Analyze the shape of cyclic voltammograms in Origin or Excel
software and use values of I p and E p to determine the electrode
processes (see Notes 1 and 2).
7. Figure 2 shows that E p of quercetin-2HP-β-CD complex in
solution at different pH values differs, signifying that protons
participate in the oxidation (see Note 3). The dependence of
E p /pH indicates the ratio between the number of participating
protons and electrons [21, 23].
1. Prepare the solutions of the drug and of the CD-drug complex
in anoxic conditions, by bubbling argon in all vials and solvent
used for their preparation.
2. Transfer the blank solution to the spectroelectrochemical cell
and record the blank, against which absorption spectra will be
recorded. Remove the blank solution from the cell.
3. Transfer the target solution to the spectroelectrochemical cell
by a syringe under inert atmosphere.
4. Set up the potentiostat to perform cyclic voltammetry experiments with a scan rate of 5 mV/s, or to perform chronoamperometry for 300-s time.
5. In order to monitor the spectral changes during the electron
transfer, set the spectrophotometer for kinetics measurement to
record spectra every 3 s, sufficient to recognize the redox intermediates and products.
6. Start simultaneously the application of potential by the potentiostat and the monitoring of absorption spectra by the spectrophotometer. Plot register data in Origin or Excel software
(Fig. 3).
7. Clean first the surface of the platinum working electrode
mounted on the cell by washing it with solvents (water, ethanol,
acetone, acetonitrile) and afterwards by electrochemical cleaning (see Note 4).
3.2 The Generation
of Oxidation Products
Electrochemically
3.2.1 In Situ UV–Vis
Spectroelectrochemistry
Romana Sokolová and Ilaria Degano