Conductivity Testing

Conductivity measures a substance’s ionic strength and helps confirm that reagent concentration stays within range, avoiding skewed results. Learn more about conductivity testing for custom-made reagents before release.

Considerations and Limitations of Conductivity Testing

Temperature of the Solution

Conductivity is temperature-sensitive, with higher temperatures increasing conductance. Ensure temperature compensation for consistency.

Concentration of the Solution

Extremely concentrated solutions may affect the outcome of the conductivity reading and should be diluted from a 1X to a 10X solution prior to performing the conductivity test.

Ionic Strength of Reagents Ambient Gases

Ambient air can influence conductivity, particularly carbon dioxide (CO₂) as it forms the carbonic acid (H₂CO₃), which dissociates into ions in solution.

USP <644> Conductivity of Solutions, United States Pharmacopeial Convention, 12601 Twinbrook Parkway, Rockville, MD 20852-1790, USA. www.usp.org.
Hacyan, S. (2023). Electricity and magnetism. In The mathematical representation of physical reality (pp. 31-38). Springer1.
Bešter-Rogač, M., & Habe, D. (2006). Modern advances in electrical conductivity measurements of solutions. 391-Beser-Rogac.indd (researchgate.net).
USP <645> Water Conductivity, United States Pharmacopeial Convention, 12601 Twinbrook Parkway, Rockville, MD 20852-1790, USA. www.usp.org.

Considerations and Limitations of Conductivity Testing
Temperature of the Solution	Conductivity is temperature-sensitive, with higher temperatures increasing conductance. Ensure temperature compensation for consistency.
Concentration of the Solution	Extremely concentrated solutions may affect the outcome of the conductivity reading and should be diluted from a 1X to a 10X solution prior to performing the conductivity test.
Ionic Strength of Reagents Ambient Gases	Ambient air can influence conductivity, particularly carbon dioxide (CO₂) as it forms the carbonic acid (H₂CO₃), which dissociates into ions in solution.

References

USP <644> Conductivity of Solutions, United States Pharmacopeial Convention, 12601 Twinbrook Parkway, Rockville, MD 20852-1790, USA. www.usp.org.
Hacyan, S. (2023). Electricity and magnetism. In The mathematical representation of physical reality (pp. 31-38). Springer1.
Bešter-Rogač, M., & Habe, D. (2006). Modern advances in electrical conductivity measurements of solutions. 391-Beser-Rogac.indd (researchgate.net).
USP <645> Water Conductivity, United States Pharmacopeial Convention, 12601 Twinbrook Parkway, Rockville, MD 20852-1790, USA. www.usp.org.