Voltammetry
Methods:
1. Potentiometry:
a. Measures potential of electrochemical cell in absence of current
b. E.g. ion selective electrodes, glass electrode
2. Voltammetry:
a. Measures cell current as function of applied potential under conditions of
electrode polarization
b. Polarography: form of voltammetry using dropping mercury electrode
c. Amperometry: form of voltammetry where measured current is proportional to
analyte concentration at fixed potential
d. E.g. oxygen sensor, glucose sensor
3. Coulometry:
a. Based on quantitative conversion to new oxidation state
b. Constant potential methods, constant current methods, electrogravimetry
Linear Scan Voltammetry:
- Energy of electrode matches or exceeds redox potential of species, current flows as
electrons are exchanged between electrode and valence orbitals of electroactive species
of interest
- Max current is limited by ability of electroactive species to diffuse and react at electrode
- Voltage tells us about species
- Magnitude tells us about quantity of species in solution
Voltammogram:
- Limiting current (Id): info about rate of delivery of material to electrode surface, related
to concentration
