Loss on Ignition Test Procedure as per IP & USP

Discover the comprehensive guide on the General Test Procedure for Loss on Ignition, aligned with IP and USP pharmacopoeia standards.

Loss on Ignition Test Procedure

1.0     Objective

    • The objective of this GTP is to describe the procedure to be used for performing loss on ignition test.

2.0     Principle/Reaction

    • It is a quantitative measuring technique used to find out presence of inorganic impurities.
    • It can be measured in terms of % w/w of the substance being examined.

3.0     Requirements for Loss on Ignition Test

    • As per IP
    • Silica or platinum crucible
    • Muffle furnace
    • Desiccator
    • Analytical balance
    • As per USP
    • Silica or platinum crucible
    • Muffle furnace
    • Desiccator
    • Analytical balance

4.0     Procedure for Determining of Loss on Ignition

    • Loss on Ignition as per IP 

    • Weigh a silica or platinum crucible, complete with the lid, previously ignited for 1 hour at the temperature specified for the test and cooled in a desiccator.
    • Transfer to the crucible the quantity of the substance specified in the individual monograph, without any treatment, unless a preliminary drying at a lower temperature or other special treatment is specified.
    • Weigh accurately the crucible, lid and the contents. Place the loaded uncovered crucible and cover in a suitable muffle furnace or oven that is capable of maintaining a temperature within 25°C of that required for the test.
    • Ignite the crucible for the period of time and at the temperature stated in the monograph.
    • Ignite for successive 1-hour periods where ignition to constant weight is indicated.
    • Upon the completion of each ignition, cover the crucible and allow it to cool in a desiccator to room temperature before weighing.

    • Loss on Ignition as per USP

    • Perform the test on finely powdered material, and break up lumps, if necessary, with the aid of a mortar and pestle before weighing the specimen.
    • Weigh the specimen to be tested without further treatment, unless a preliminary drying at a lower temperature, or other special pretreatment, is specified in the individual monograph.
    • Unless other equipment is designated in the individual monograph, conduct the ignition in a suitable muffle furnace or oven that is capable of maintaining a temperature within 25° of that required for the test, and use a suitable crucible, complete with cover, previously ignited for 1 hour at the temperature specified for the test, cooled in a desiccator, and accurately weighed.
    • Unless otherwise directed in the individual monograph, transfer to the tared crucible an accurately weighed quantity, in g, of the substance to be tested, about equal to that calculated by the formula:

10 / L

    • in which L is the limit (or the mean value of the limits) for Loss on ignition, in percentage.
    • Ignite the loaded uncovered crucible, and cover at the temperature (±25°C) and for the period of time designated in the individual monograph.
    • Ignition to constant weight is indicated for successive 1-hour periods where it is ignited.
    • Upon completions of each ignition, cover the crucible, and allow it to cool in a desiccator to room temperature before weighing.
Tags: ,

Leave a Reply