27 September 2022
In the European Pharmacopoeia (Ph. Eur.) Supplement 10.6, published in July 2021, a new general chapter 2.1.7 Balances for Analytical Purposes was included. It complements existing guidelines for the use and qualification of balances published elsewhere. The scope of the new chapter is limited to balances used for analytical purposes. Balances used for manufacturing and other purposes are not covered.
In a press release of the European Pharmacopoeia Commission it is stated that "this addition to section 2.1. Apparatus fills a long-standing gap by setting out clear requirements for a piece of equipment that is the cornerstone of every analytical procedure described in the Ph. Eur. Weighing is one of the most common but also most critical tasks in a laboratory, as even the smallest weighing error can propagate throughout the whole analysis, affecting the accuracy of reported results."
2.1.7 Balances for Analytical Purposes
The new chapter is divided into the following sections:
The new chapter first gives an overview of the principles. Electronic balances and mechanical balances are mentioned. However, it is clear that most of the balances used in the laboratory are electronic and based on force compensation. The subchapter on equipment includes information regarding installation and location and good practices for weighing vessels. The subchapter on equipment performance provides detailed information on calibration and carrying out performance checks (in particular repeatability and sensitivity) during routine use and between calibrations. The use of reference weights and built-in weights is described. The last two subchapters address the weighing process itself and how to handle samples.
The principles outlined in the new chapter apply to all weighings performed as part of analytical procedures prescribed to establish compliance with a Ph. Eur. text. In addition, the European Pharmacopoeia (Ph. Eur.) Commission adopted a revised version of Ph. Eur. Chapter 1 General Notices to provide greater clarity for users. It will be published in Ph. Eur. Supplement 10.7, available in October 2021 (implementation date: 1 April 2022). Quantities (1.2.1) will include a reference to the new chapter 2.1.7.