Apparatus and procedures

Apparatus and procedures
Volumetric glassware complies with Class A requirements of the appropriate International Standard issued by the International Organisation for Standardisation.
Unless otherwise prescribed, analytical procedures are carried out at a temperature between 15 °C and 25 °C.
Unless otherwise prescribed, comparative tests are carried out using identical tubes of colourless, transparent, neutral glass with a flat base; the volumes of liquid prescribed are for use with tubes having an internal diameter of 16 mm but tubes with a larger internal diameter may be used provided the volume of liquid used is adjusted (2.1.5). Equal volumes of the liquids to be compared are examined down the vertical axis of the tubes against a white background, or if necessary against a black background. The examination is carried out in diffuse light.
Any solvent required in a test or assay in which an indicator is to be used is previously neutralised to the indicator, unless a blank test is prescribed.