Traceable Standards for Electrolytic Conductivity Measurements Required for Pharmaceutical Production

Abstract

Certified reference materials for low electrolytic conductivity can now be produced successfully that meet the basic criteria of a high quality technical standard for industrial purposes. The materials are very stable and easy to handle. The values for these high quality references have low uncertainties and are traceable to international standards by an unbroken chain of comparison. These certified reference materials can be used to check the compliance with the requirements for pharmaceutical grades of water. Water for injection (WFI) or highly purified water (HPW) can now be checked reliably against the limiting values set by the European and United States Pharmacopeia using instruments that are calibrated with low level electrolytic standards. The comparability of the results has been demonstrated on occasion of an intercomparison between expert reference laboratories.