Soda Lime
» Soda Lime is a mixture of Calcium Hydroxide and Sodium or Potassium Hydroxide or both.
It may contain an indicator that is inert toward anesthetic gases such as Ether, Cyclopropane, and Nitrous Oxide, and that changes color when the Soda Lime no longer can absorb Carbon Dioxide.
Identification—
A:
Place a granule of it on a piece of moistened red litmus paper: the paper turns blue immediately.
B:
A solution in 6 N acetic acid responds to the tests for Calcium 
191
. It also imparts a yellow color to a nonluminous flame that, when viewed through cobalt glass, may show a violet color.
191. It also imparts a yellow color to a nonluminous flame that, when viewed through cobalt glass, may show a violet color.
Loss on drying 731—
Weigh accurately, in a tared weighing bottle, about 10 g, and dry at 105
for 2 hours: it loses between 12.0% and 19.0% of its weight.
731—
Weigh accurately, in a tared weighing bottle, about 10 g, and dry at 105 for 2 hours: it loses between 12.0% and 19.0% of its weight.
Moisture absorption—
Place about 10 g in a tared, 50-mL weighing bottle, having a diameter of 50 mm and a height of 30 mm, and weigh. Then place the bottle, with cover removed, for 24 hours in a closed container in which the atmosphere is maintained at 85% relative humidity by being in equilibrium with sulfuric acid having a specific gravity of 1.16. Weigh again: the increase in weight is not more than 7.5%.
Hardness—
Screen 200 g on a mechanical sieve shaker (see Particle Size Distribution Estimation by Analytical Sieving 786) having a frequency of oscillation of 285 ± 3 cycles per minute, for 3 minutes, to remove granules both coarser and finer than the labeled particle size. Proceed as directed in the test for Hardness under Barium Hydroxide Lime, beginning with “Weigh 50 g of the granules.” The percentage of Soda Lime retained on the screen is not less than 75.0, and represents the hardness.
786) having a frequency of oscillation of 285 ± 3 cycles per minute, for 3 minutes, to remove granules both coarser and finer than the labeled particle size. Proceed as directed in the test for Hardness under Barium Hydroxide Lime, beginning with “Weigh 50 g of the granules.” The percentage of Soda Lime retained on the screen is not less than 75.0, and represents the hardness.
Carbon dioxide absorbency—
Proceed as directed in the test for Carbon dioxide absorbency under Barium Hydroxide Lime. The increase in weight is not less than 19.0% of the weight of Soda Lime used for the test.
Other requirements—
It meets the requirements for Packaging and storage, Labeling, and Size of granules under Barium Hydroxide Lime.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
| Monograph | Radhakrishna S Tirumalai, Ph.D.
Senior Scientist 1-301-816-8339 |
(GTMDB05) General Toxicology and Medical Device Biocompatibility |
USP32–NF27 Page 1339