A: Infrared Absorption 197F.

B: The retention time for the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of a similar preparation of USP Acetyltriethyl Citrate RS.

System suitability solution— Prepare a solution in toluene containing about 30 mg each of USP Acetyltriethyl Citrate RS and USP Triethyl Citrate RS per mL.

Assay preparation— Transfer about 300 mg of Acetyltriethyl Citrate, accurately weighed, to a 10-mL volumetric flask, dissolve in and dilute with toluene to volume, and mix.

Chromatographic system (see Chromatography 621)— The gas chromatograph is equipped with an on-column, temperature-programmable injector, a flame-ionization detector maintained at about 275, and a 0.32-mm × 30-m column bonded with a 0.5-µm layer of phase G42. The column temperature is programmed as follows. Initially the temperature of the column is maintained at about 80 for 0.5 minute, then increased at a rate of 20 per minute to about 220, and maintained at about 220 for 10 minutes. The injection port temperature is programmed as follows. Initially the temperature is maintained at about 85 for 0.5 minute, then increased at a rate of 20 per minute to about 225, and maintained at about 225 for 10 minutes. The carrier gas is helium, flowing at a rate of about 2.3 mL per minute. Chromatograph the System suitability solution, and record the peak responses as directed for Procedure: the relative retention times are about 0.9 for triethyl citrate and 1.0 for acetyltriethyl citrate; the resolution, R, between triethyl citrate and acetyltriethyl citrate is not less than 1.5; and the relative standard deviation for replicate injections is not more than 2.0% determined from both the triethyl citrate and acetyltriethyl citrate peaks, based on area percent calculation.

Procedure— Inject 1 µL of the Assay preparation into the chromatograph, record the chromatogram, and measure all of the peak areas, excluding the solvent peak. Calculate the percentage of C14H22O8 in the portion of Acetyltriethyl Citrate taken by the formula: in which A is the acetyltriethyl citrate peak area response; and B is the sum of the area responses of all the peaks.