Several reference materials for use in testing instruments are described in the European pharmacopoeias (e.g. Ph Eur. 2.2.6). In this case, the substances trimethylpentane, toluene and methylnaphthalene are prescribed. This instrument test should be carried out prior to every analysis. The comprehensive product range includes standards suitable for practically every operating range; the range 1,3915 to 1,6160 (20 °C) is covered.