# Commission Regulation (EEC) No 2568/91 of 11 July 1991 on the characteristics of olive oil and olive-residue oil and on the relevant methods of analysis, Division 5.2.1: Preparatory work

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

Fit the column to the gas chromatograph (3.3) by connecting the inlet port to the on-column system and the outlet port to the detector. Perform a general check on the GC apparatus (operation of gas circuits, detector and recorder efficiency, etc.).
If the column is being used for the first time it should be conditioned first. Pass a little gas through the column, then turn on the GC apparatus. Heat gradually until 350 °C is reached after about four hours. Maintain that temperature for at least two hours then regulate the apparatus to operating conditions (set gas flow, light flame, connect to the electronic recorder (3.3.4), set temperature of column chamber, detector, etc.) and record the signal at a sensitivity at least twice as high as that required for the analysis. The baseline must be linear, with no peaks of any kind, and must not show any deviation.
A negative straight-line drift indicates that the column connections are not tight; a positive drift that the column has not been sufficiently conditioned.

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Source: https://www.legislation.gov.uk/eur/1991/2568/annex/IV/division/5/division/5.2/division/5.2.1 (the official version)
Page: https://openlegislation.uk/eu-regulation-1991-2568/annex-IV/division-5/division-5.2/division-5.2.1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.