A: Infrared Absorptioná197Kñ.

B: Asolution (1in 100)responds to the tests for Iodide á191ñ.

Sodium perchlorate buffer— Prepare a 0.14Msolution of sodium perchlorate in water,and adjust with 10Nsodium hydroxide or 0.05Mphosphoric acid to a pHof 3.0.

Mobile phase— Prepare a filtered and degassed mixture of Sodium perchlorate bufferand acetonitrile (69:31).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard preparation— Dissolve an accurately weighed quantity of USP Gallamine Triethiodide RSin Mobile phase,and dilute quantitatively,and stepwise if necessary,with Mobile phaseto obtain a solution having a known concentration of about 1.0mg per mL.

Assay preparation— Transfer about 25mg of Gallamine Triethiodide,accurately weighed,to a 25-mLvolumetric flask,dissolve in and dilute with Mobile phaseto volume,and mix.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 200-nm detector and a 4.6-mm ×25-cm column that contains packing L1.The flow rate is about 1.0mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed under Procedure:the column efficiency is not less than 5000theoretical plates,the tailing factor is not more than 1.4,and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 10µL)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 C30H60I3N3O3in the portion of Gallamine Triethiodide taken by the formula: in which Cis the concentration,in mg per mL,of USP Gallamine Triethiodide RSin the Standard preparation,and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.