# Fourth Commission Directive of 11 October 1985 on the approximation of the laws of the Member States relating to methods of analysis necessary for checking the composition of cosmetic products (85/490/EEC), Division 6.2.1: The operating conditions must yield a resolution factor R ≥ 1,5.

Extent: E+W+S+N.I.

R = 2 d'R 2 — d'R 2 W 1 + W 2 Where
R1 and R2 retention times, in minutes, of the peaks,
W1 and W2 peak widths at half height, in millimetres,
d' the chart speed, in millimetres per minute.

---
Source: https://www.legislation.gov.uk/eudr/1985/490/annex/division/2/division/1/division/6/division/6.2/division/6.2.1 (the official version)
Page: https://openlegislation.uk/eu-directive-1985-490/annex/division-2/division-1/division-6/division-6.2/division-6.2.1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.