Validation of titration methods
31. 5. 2021
Článek
Manufacturing products of the highest quality is a must, especially in the pharmaceutical and food industries. This requires accurate, reproducible, and simple analysis methods that eliminate human errors as much as possible. Automated titration is one such solution that offers additional time and cost savings to laboratories.
After applying automation to a titration method, how can you ensure that the chosen method also delivers a reliable result? And how do you know that it is suitable for the analysis of your analyte(s)? This requires method validation of a titration, which includes standardization of the titrant as well as determination of accuracy and precision, linearity, and specificity.
USP General Chapter <1225> Validation of Compendial Procedures and ICH Guidance Q2(R1) Validation of Analytical Procedures: Text and Methodology define the validation elements – some of the most important ones are described in the following article.
These include (click to go directly to each section):
Standardization
Dilution and weighing errors as well as the constant aging of all titrants lead to changes in the concentration of the titrant. To obtain results that are as reliable as possible, the most accurate titrant concentration is a prerequisite. Standardization of the titrant is therefore an integral part of a titration method validation. The standardization procedures for various titrants are described in the Volumetric Solution section of USP – NF as well as in the free Application Bulletin AB-206 below regarding the titer determination in potentiometry.
AB-206 – Titer determination in potentiometry
The titrant to be used in the validation must first be standardized against a primary standard or a pre-standardized titrant. It is important that the standardization step and the sample titration are carried out at the same temperature.
Primary standards are characterized by the following properties:
- high purity and stability
- low hygroscopicity (to minimize weight changes)
- high molecular weight (to minimize weighing errors)
The use of a standard substance (primary standard) allows accuracy to be assessed.
For more information about titrant standardization, check out our other related blog posts: