Potassium Perchlorate
»Potassium Perchlorate contains not less than 99.0percent and not more than 100.5percent of KClO4,calculated on the dried basis.
Caution—Great care should be taken in handling Potassium Perchlorate in solution or in the dry state,as explosions may occur if it is brought into contact with organic or other readily oxidizable substances.
Packaging and storage— Preserve in well-closed containers.
Identification—
A: Ignite a small portion of a solution (1in 10)on a platinum wire in a nonluminous flame:a transient violet color is imparted to the flame.
B: Add a few drops of methylene blue solution (1in 1000)to the solution (1in 10):a violet-colored precipitate is formed.
pHá791ñ: between 5.0and 6.5,in a 0.1Msolution.
Loss on drying á731ñ— Dry it over silica gel for 12hours:it loses not more than 0.5%of its weight.
Insoluble substances— Dissolve 20g in 150mLof warm water,pass through a tared medium-porosity filtering crucible,and wash with three 50-mLportions of warm water.Dry the residue at 105for 3hours:the weight of the residue does not exceed 1mg (0.005%).
Chloride á221ñ— A5.0-g portion shows no more chloride than corresponds to 0.20mLof 0.020Nhydrochloric acid (0.003%).
Limit of sodium— Ignite a small portion of a solution (1in 10)on a platinum wire in a nonluminous flame:no pronounced yellow color is imparted to the flame.
Organic volatile impurities,Method Iá467ñ: meets the requirements.
Assay—
Mobile phase— Transfer 16.6g of phthalic acid to a 100-mLvolumetric flask,dissolve in and dilute with methanol to volume,and mix.Transfer 10.0mLof this solution to a 1000-mLflask,dilute with water to volume,and mix.Adjust with about 450mg of lithium hydroxide to a pHof 4.5,filter,and degas.
Standard preparation— Transfer about 50mg of USP Potassium Perchlorate RS,accurately weighed,to a 50-mLvolumetric flask,dilute with water to volume,and mix.Transfer 10.0mLof this solution to a 100-mLvolumetric flask,dilute with water to volume,and mix to obtain a solution having a known concentration of about 0.1mg per mL.
Assay preparation— Using about 50mg of Potassium Perchlorate,accurately weighed,proceed as directed for the Standard preparation.
Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a conductivity detector and a 4.6-mm ×7.5-cm column that contains 6-µm packing L23.The flow rate is about 1.2mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the tailing factor is not more than 1.5;and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure— Separately inject equal volumes (about 50µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of KClO4in the portion of Potassium Perchlorate taken by the formula:
500C(rU/rS),
in which Cis the concentration,in mg per mL,of USP Potassium Perchlorate RSin the Standard preparation;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information— Staff Liaison:Andrzej Wilk,Ph.D.,Senior Scientific Associate
Expert Committee:(RMI)Radiopharmaceuticals and Medical Imaging Agents
USP28–NF23Page 1597
Phone Number:1-301-816-8305