What are Carbon Paste Electrodes?

A carbon paste electrode is a particular type of electrochemical sensor widely used in voltammetric experiments. The electrode is made up of carbon paste; a mixture of a binder or pasting liquid and carbon powder. It was invented by Ralph Norman Adams in 2008.

Types of Carbon Paste Electrode

Carbon paste electrodes are classified into two types – biologically/chemically modified, or unmodified electrodes.

According to Svancara et al. (2009), modified electrodes are formed using different types of carbonaceous materials, such as carbon nanotubes, carbon microspheres, carbon nanofibers, diamond, acetylene black, and graphite.

Preparation of Carbon Paste Electrodes

According to a report published by Vytras et al. (2009), carbon paste electrodes are generally prepared by combining the carbonaceous material and the binder. The mixture is blended to obtain a paste with excellent consistency. The paste is usually filled in a holder which is a polyethylene syringe, glass tube or Teflon rod electrically connected by a conducting wire.

However, this type of electrode construction is not ideal for practical applications due to the frequent filling of carbon paste for experiments that involve the extraction of the surface layer of the electrodes. The more advanced design employs electrode holders that are driven by a piston. In this type, the carbon paste used can be mechanically expelled from the electrode structure.

Advantages of Carbon Paste Electrodes

The key benefits of carbon paste electrodes include:

• Low cost
• Simple design
• Low background current
• Ability to introduce various modifiers during paste preparation
• Easy removal of electrode surface layer
• Low ohmic resistance
• Wide potential range

Applications of Carbon Paste Electrodes

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Some of the major applications areas of carbon paste electrodes include:

• Coulometric applications
• Electrocatalytic determination of hydroxylamine in pharmaceutical and water samples
• Glucose biosensor applications
• Determination of polyphenols in tea and wine
• Determining the presence of adrenaline
• Detecting acetaminophen, aspirin, and caffeine

Sources and Further Reading

• Svancara I et al, Carbon Paste Electrodes in Facts, Numbers, and Notes: A Review on the Occasion of the 50-Years Jubilee of Carbon Paste in Electrochemistry and Electroanalysis, Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim, 2009, 21 (1), 7-28
• Vytras k et al, Carbon paste electrodes in electroanalytical chemistry, Journal of the Serbian Chemical Society, 2009, 74 (10), 1021–1033
• Shankar SS, Shereema RM, Rakhi RB. Electrochemical Determination of Adrenaline using MXene/Graphite composite paste electrodes. ACS applied materials & interfaces. 2018 Nov 22;10(50):43343-51.
• Sanghavi BJ, Srivastava AK. Simultaneous voltammetric determination of acetaminophen, aspirin and caffeine using an in situ surfactant-modified multiwalled carbon nanotube paste electrode. Electrochimica Acta. 2010 Dec 1;55(28):8638-48.

This article was updated on the 30^th May, 2019.