Further Revision of Ph. Eur. General Chapter 2.2.46 Concerning Signal-to-Noise Ratio

Recommendation

3/4 February 2026

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As already reported a few months ago, a revised general chapter 2.2.46. Chromatographic separation techniques has been published in Ph. Eur. 11.0. The implementation date is 01 January 2023.

One of the changes is the sensitivity requirement. According to the revised chapter, the signal-to-noise (S/N) ratio is calculated on a window of 20 times the peak width at half height (“20 x Wh”). In contrast, from Ph. Eur. Supplement 6.4 through Supplement 10.8, the S/N ratio is calculated on a window of at least 5 times the peak width at half height (“at least 5 x Wh”).

In this context, the EDQM has now published a press release dated 14 December 2022, stating that this change might be technically challenging for a number of users. Therefore, there will be another revision, which will be included in Supplement 11.3 (to be published in July 2023 and implemented on 01 January 2024).

The EDQM writes that in the meantime "Ph. Eur. users are advised to continue calculating the S/N ratio on a window “at least 5 x Wh”, instead of “20 x Wh”."

Please also see the supporting information in the EDQM knowledge database.