# Commission Regulation (EC) No 152/2009 of 27 January 2009 laying down the methods of sampling and analysis for the official control of feed (Text with EEA relevance), Division 3.3

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

Requirements for GC-MS techniques
Monitoring of at least the following number of molecular ions or characteristic ions from the molecular cluster:
(a)two specific ions for HRMS;
(b)three specific ions for LRMS;
(c)two specific precursor ions, each with one specific corresponding transition product ion for for MS-MS.
Maximum permitted tolerances for abundance ratios for selected mass fragments:
Relative deviation of abundance ratio of selected mass fragments from theoretical abundance or calibration standard for target ion (most abundant ion monitored) and qualifier ion(s): ± 15 %

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Source: https://www.legislation.gov.uk/eur/2009/152/annex/V/division/B/chapter/III/division/3/division/3.3 (the official version)
Page: https://openlegislation.uk/eu-regulation-2009-152/annex-V/division-B/chapter-III/division-3/division-3.3
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.