Appendix XI A. Total Solids

The term ‘total solids’ is applied to the residue obtained when the prescribed amount of the preparation is dried to constant weight under the conditions specified below.

Apparatus

A shallow, flat-bottomed, flanged dish, about 75 mm in diameter and about 25 mm deep, made of nickel or other suitable metal of high heat conductivity and low specific heat and which is not affected by boiling water. Suitable dishes are described in British Standard 1742:1951 (Methods for the chemical analysis of condensed milk).

Method

Place the quantity stated in the monograph in a tared dish, evaporate at as low a temperature as possible until the ethanol is removed and heat on a water-bath until the residue is apparently dry. Transfer to an oven operating without a fan and dry to constant weight at 105° unless otherwise stated in the monograph. It may be necessary, for residues of a hygroscopic nature, to use a dish provided with a well-fitting cover and to cool in a desiccator.