295
3. Derivatization procedure: Add 30 μL of the derivatization
agent BSTFA in 50 μL of AcOEt to the dried sample. The reaction takes place at 60 °C for 30 min into closed glass vials
inserted in a water bath. Just before injection, add 10 μL of
hexadecane (solution in iso-octane; internal standard IS2) and
150 μL of AcOEt.
1. Possibly you may need to dilute the aliquot of the sample containing quercetin and its possible electrolysis products with
water.
2. Insert the sample in autosampler vials and inject a suitable
amount in the chromatographic system automatically.
3. Acquire the chromatogram in the 200–650 nm range.
1. Possibly you may need to dilute the aliquot of the sample containing quercetin and its possible electrolysis products with
water.
2. Insert the sample in autosampler vials and inject a suitable
amount in the chromatographic system automatically.
3. Acquire the chromatogram in unsupervised, untargeted tandem mass spectrometric acquisition mode.
4 Notes
1. The linear dependence of I p on the square root of scan rate is
characteristic for a diffusion-controlled electrode process.
2. Figure 2 shows that cyclic voltammograms of quercetin-2HPβ-CD complex and quercetin do not differ neither in E p nor in
I p indicating that all electroactive sites of quercetin encapsulated
in the cavity are available for oxidation.
3. The oxidation waves belonging to the oxidation of nondissociated drug complexed by cyclodextrin, its dissociated
form, and dianionic form are labeled in cyclic voltammograms
recorded at different pH.
4. Electrochemical cleaning of the cell: The cell is washed by acetonitrile; then, 0.1 M tetrabutylammonium hexafluorophosphate
in acetonitrile is inserted into the cell. A potential of −1.9 V is
applied for 100 s. The cell is then washed carefully by acetonitrile and acetone.
5. The charge Q in coulombs consumed during the electrolysis
will give information about the number of electrons participating in the redox process. It is calculated using Eq. (2):
Q mz
=
F M
/
(2)
3.3.2 HPLC-DAD
Chromatography
3.3.3 HPLC-MS/MS
Chromatography
Electrochemistry Investigation of Drugs Encapsulated in Cyclodextrins
3. Derivatization procedure: Add 30 μL of the derivatization
agent BSTFA in 50 μL of AcOEt to the dried sample. The reaction takes place at 60 °C for 30 min into closed glass vials
inserted in a water bath. Just before injection, add 10 μL of
hexadecane (solution in iso-octane; internal standard IS2) and
150 μL of AcOEt.
1. Possibly you may need to dilute the aliquot of the sample containing quercetin and its possible electrolysis products with
water.
2. Insert the sample in autosampler vials and inject a suitable
amount in the chromatographic system automatically.
3. Acquire the chromatogram in the 200–650 nm range.
1. Possibly you may need to dilute the aliquot of the sample containing quercetin and its possible electrolysis products with
water.
2. Insert the sample in autosampler vials and inject a suitable
amount in the chromatographic system automatically.
3. Acquire the chromatogram in unsupervised, untargeted tandem mass spectrometric acquisition mode.
4 Notes
1. The linear dependence of I p on the square root of scan rate is
characteristic for a diffusion-controlled electrode process.
2. Figure 2 shows that cyclic voltammograms of quercetin-2HPβ-CD complex and quercetin do not differ neither in E p nor in
I p indicating that all electroactive sites of quercetin encapsulated
in the cavity are available for oxidation.
3. The oxidation waves belonging to the oxidation of nondissociated drug complexed by cyclodextrin, its dissociated
form, and dianionic form are labeled in cyclic voltammograms
recorded at different pH.
4. Electrochemical cleaning of the cell: The cell is washed by acetonitrile; then, 0.1 M tetrabutylammonium hexafluorophosphate
in acetonitrile is inserted into the cell. A potential of −1.9 V is
applied for 100 s. The cell is then washed carefully by acetonitrile and acetone.
5. The charge Q in coulombs consumed during the electrolysis
will give information about the number of electrons participating in the redox process. It is calculated using Eq. (2):
Q mz
=
F M
/
(2)
3.3.2 HPLC-DAD
Chromatography
3.3.3 HPLC-MS/MS
Chromatography
Electrochemistry Investigation of Drugs Encapsulated in Cyclodextrins