Voltammetry
Also known as: electrochemical voltammetry, cyclic voltammetry, CV, differential pulse voltammetry
Voltammetry is an electrochemical analytical technique that studies chemical reactions and properties of substances by measuring the current response as the potential applied to an electrode is systematically varied. Developed by Jaroslav Heyrovsky in the 1920s (polarography), modern voltammetry has become essential for measuring redox potentials, detecting trace analytes, and investigating reaction mechanisms. Variants such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV) offer high sensitivity and selectivity for electrochemically active analytes.
Key highlights
- High selectivity by controlling applied electrode potential
- Rapid analysis (seconds to minutes per sample)
- Non-destructive in reversible reactions; sample can be recovered
- Provides mechanistic information on electron transfer and coupled reactions
- Excellent sensitivity for suitable analytes (trace level detection possible)
- Minimal sample preparation required
Intuition
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How it works
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When to use it
Voltammetry is ideal for analyzing electrochemically active organic molecules (polycyclic aromatics, vitamins, antioxidants), metal ions, and reactive species (oxygen, hydrogen peroxide). Use voltammetry when selectivity via electrode potential is valuable, when real-time kinetic information is needed, or when coupled with chromatography (voltammetric detection in HPLC). Cyclic voltammetry is particularly useful for mechanistic studies and exploratory analysis; differential pulse voltammetry provides superior sensitivity for trace quantification.
Strengths & limitations
- High selectivity by controlling applied electrode potential
- Rapid analysis (seconds to minutes per sample)
- Non-destructive in reversible reactions; sample can be recovered
- Provides mechanistic information on electron transfer and coupled reactions
- Excellent sensitivity for suitable analytes (trace level detection possible)
- Minimal sample preparation required
- Only applicable to electrochemically active analytes (molecules with redox-active functional groups)
- Electrode fouling or contamination compromises signal and repeatability
- Interference from residual oxidation/reduction of solvent or supporting electrolyte (capacitive current)
- Requires deoxygenation, which adds time and introduces potential for contamination
- Quantification relies on comparison to standards; not an absolute method
Common pitfalls
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Applications
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Frequently asked
What is the difference between cyclic voltammetry and linear sweep voltammetry?
Linear sweep voltammetry scans the potential in one direction from an initial value to a final value and back to the starting point in a single ramp. Cyclic voltammetry repeats this back-and-forth cycle multiple times, allowing observation of how the system responds as the potential cycles. Multiple cycles reveal any changes in electrode behavior or analyte concentration, and the comparison of forward and reverse scans reveals information about electron transfer kinetics and reversibility.
Why is deoxygenation necessary before voltammetric analysis?
Dissolved oxygen is easily reduced at most electrode potentials, producing a large background current that obscures analyte signals. Additionally, oxygen reduction can interfere with the analyte reaction and cause spurious peaks. Deoxygenation (typically by bubbling nitrogen gas) removes oxygen to yield a clean baseline and sensitive analyte detection.
How do I determine the number of electrons transferred in a redox reaction using voltammetry?
The number of electrons (n) can be estimated from the peak width and shape in cyclic voltammetry: the peak width (in mV) is roughly proportional to RT/nF. More rigorous determination uses the Nicholson-Shain equations, which relate peak current and peak potential to the electron transfer rate and number. Rotating disk electrode voltammetry also yields n from the Levich equation relating current to electrode rotation rate.
What is differential pulse voltammetry (DPV), and when should I use it?
DPV applies small potential pulses superimposed on a linearly increasing base potential, measuring current difference between the baseline and pulse. This technique reduces capacitive background current and noise, improving signal-to-noise ratio by 10–100 fold compared to linear sweep. Use DPV for trace analysis and when analyte concentration is very low; use cyclic voltammetry for mechanistic studies and qualitative identification.
Can voltammetry be used with complex matrices, or do I need separation?
Voltammetry has moderate selectivity based on electrode potential; multiple redox-active species may produce overlapping peaks. For complex matrices, integration with chromatography (HPLC-ECD: high-performance liquid chromatography with electrochemical detection) provides superior selectivity by separating analytes before detection. Alternatively, computational deconvolution techniques can resolve overlapping voltammetric peaks in some cases.
Sources
- 1.Nicholson, R. S., & Shain, I. (1965). Theory of stationary electrode polarography for a chemical reaction coupled to electron transfer. Analytical Chemistry, 36(4), 706–723.
- 2.Bard, A. J., & Faulkner, L. R. (2001). Electrochemical Methods: Fundamentals and Applications (2nd ed.). John Wiley & Sons.ISBN 978-0471044925
- 3.Bond, A. M. (1994). Modern Polarographic Methods in Analytical Chemistry. Marcel Dekker.ISBN 978-0824790868
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Cite this page
ScholarGate. (2026, June 3). Voltammetry. ScholarGate. https://scholargate.app/analytical-chemistry/voltammetry