Appendix IX D. Determination of Loss on Drying

Loss on drying is the loss of mass expressed as per cent m/m.

Method Place the prescribed quantity of the substance to be examined in a weighing bottle previously dried under the conditions prescribed for the substance to be examined. Dry the substance to constant mass or for the prescribed time by one of the following procedures. Where the drying temperature is indicated by a single value rather than a range, drying is carried out at the prescribed temperature ± 2 °C.

a) "in a desiccator": the drying is carried out over diphosphorus pentoxide R at atmospheric pressure and at room temperature;

b) "in vacuo": the drying is carried out over diphosphorus pentoxide R, at a pressure of 1.5 kPa to 2.5 kPa at room temperature;

c) "in vacuo within a specified temperature range": the drying is carried out over diphosphorus pentoxide R, at a pressure of 1.5 kPa to 2.5 kPa within the temperature range prescribed in the monograph;

d) "in an oven within a specified temperature range": the drying is carried out in an oven within the temperature range prescribed in the monograph;

e) "under high vacuum": the drying is carried out over diphosphorus pentoxide R at a pressure not exceeding 0.1 kPa, at the temperature prescribed in the monograph.

If other conditions are prescribed, the procedure to be used is described in full in the monograph.