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:
Asolution in 6Nacetic acid responds to the tests for Calcium á191ñ.It also imparts a yellow color to a nonluminous flame that,when viewed through cobalt glass,may show a violet color.
Loss on drying á731ñ—
Weigh accurately,in a tared weighing bottle,about 10g,and dry at 105
for 2hours:it loses between 12.0%and 19.0%of its weight.
for 2hours:it loses between 12.0%and 19.0%of its weight.
Moisture absorption—
Place about 10g in a tared,50-mLweighing bottle,having a diameter of 50mm and a height of 30mm,and weigh.Then place the bottle,with cover removed,for 24hours 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 200g on a mechanical sieve shaker (see Particle Size Distribution Estimation by Analytical Sieving á786ñ)having a frequency of oscillation of 285±3cycles per minute,for 3minutes,to remove granules both coarser and finer than the labeled particle size.Proceed as directed in the test for Hardnessunder Barium Hydroxide Lime,beginning with “Weigh 50g 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 absorbencyunder 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 granulesunder Barium Hydroxide Lime.
Auxiliary Information—
Staff Liaison:Radhakrishna S Tirumalai,Scientist
Expert Committee:(GTB)General Toxicology and Biocompatibility
USP28–NF23Page 3074
Phone Number:1-301-816-8339