Empower Tip: USP Chapter 621 for Chromatography

In this tip for Empower Chromatography Data System (CDS), begin a new series on the upcoming changes to USP Chapter 621 on Chromatography.

The upcoming changes to USP Chapter 621 on Chromatography will go into effect on 1 December 2022. Specifically, in this tip, we will look at the changes to the calculations which affect Empower. Those calculations are resolution, relative resolution, plate count, tailing factor and signal-to-noise ratio. These changes are being made to harmonize the calculations with the European Pharmacopeia (EP) and the Japanese Pharmacopeia (JP). Most notably, the USP will use peak widths at half height for resolution, relative resolution, and plate count, i.e., no longer using peak widths at tangent.

We begin with an understanding of the changes which will take place effective 1 December 2022.

Currently resolution is calculated using peak widths at tangent. The change to the calculation will be using peak widths at half height. Empower currently reports USP Resolution (HH), EP Resolution and JP Resolution, all of which use peak widths at half height.

Likewise, relative resolution will be calculated using peak widths at half height. Currently Empower reports relative resolution using peak widths at half height for USP, EP and JP. Selecting All or ChP, Empower will calculate relative resolution using peak widths at tangent.

Plate Count will be called Plate Number. Currently Plate Count is calculated using peak widths at tangent. The change to the calculation will be using peak widths at half height. Empower currently reports EP Plate Count and JP Plate Count, both of which use peak width at half height.

Tailing Factor will be called Symmetry Factor. There is no change to the calculation and Empower currently reports USP Tailing.

The calculation for signal-to-noise ratio remains the same. The half-height multiplier is changing from 5 to 20 for both USP and EP.

It’s that easy!