<644> Conductivity of Solutions

Expert Committee: General Chapters—Chemical Analysis
Coordinating Pharmacopoeia: USP

A revision to the harmonized standard for Conductivity of Solutions has been approved by the Pharmacopeial Discussion Group (PDG) as described in its PDG Correction of sign-off cover sheet. Having reached Stage 4 of the PDG process, the general chapter of Conductivity of Solutions has been formally approved by the USP General Chapters—Chemical Analysis Expert Committee in accordance with the Rules and Procedures of the 2015–2020 Council of Experts.

Changes from the existing USP–NF General Chapter include:

Temperature compensation

  • Replace “In cases of very low conductivity (<10 µS/cm), such as purified pharmaceutical waters, two compensations need to be made” with “In cases of very low conductivity (<10 µS/cm), such as purified water for cleaning/rinsing purposes, two compensations need to be made.”

Conductivity Measurements of Fluid

  • Replace “For off-line batch measurements” with “For off-line or at-line batch measurements”.
  • Replace “For continuous on-line or at-line measurements” with “For continuous on-line or in-line measurements”.

General Chapter <644> Conductivity of Solutions will be incorporated into and become official with the USP-NF 2021, Issue 1.

Should you have any questions about the <644> Conductivity of Solutions General Chapter, please contact Antonio Hernandez-Cardoso (301-816-8308 or ahc@usp.org. For any questions about the PDG and its processes, please see the Pharmacopeial Harmonization Web page or contact Richard Lew (240-221-2060 or rll@usp.org.