Chromatographic system (see Chromatography 621)
The gas chromatograph is equipped with a flame-ionization detector and a 4-mm × 1.8-m column packed with 10% liquid phase G8 on 100- to 120-mesh support S1A. The carrier gas is nitrogen, flowing at a rate of 45 mL per minute. The column temperature is programmed to rise from 90
to 210
at a rate of 2
per minute and then to maintain at 210
for 8 minutes. The detector temperature is maintained at 280
, and the injection port temperature is maintained at 240
. Chromatograph the
System suitability solution, and record the peak responses as directed for
Procedure: the relative retention times for isopropyl myristate and isopropyl palmitate are about 1 and 1.3, respectively; the resolution,
R, is not less than 6.0 between the peaks due to isopropyl myristate and isopropyl palmitate; the tailing factor for the isopropyl palmitate peak is not more than 2; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure
Inject about 5 µL of the
Assay preparation into the chromatograph, record the chromatogram, and measure the responses for the major peaks. Calculate the percentage of C
19H
38O
2 in the portion of Isopropyl Palmitate taken by the formula:
100A/B,
in which
A is the isopropyl palmitate peak response; and
B is the sum of the responses of all the peaks in the chromatogram, except the solvent peak.