Principles and Practice of Chromatography - Chromatography Applications > Liquid Chromatography Applications > Page 83

The chromatographic conditions were as follows.

Column LC-PCN
Column Length 25 cm
Column Diameter 4.6 mm
Column Packing C18 Reverse Phase, (cyanopropile chain) Column Temperature 30oC
Mobile Phase 25%0.01M potassium phosphate (adjusted to pH 7 with 85% phosphoric acid)60% acetonitrile and 15% methanol
Flow-Rate 2 ml/min.
Detector UV adsorption at 215 nm
Sample Volume 100ml

An example of the use of native silica is in the analysis of Darvocet® and its generic equivalent formulation. The separation obtained is shown in figure 44. Darvocet® is an acetaminophen product of which acetaminophen itself is the active ingredient together with other weakly polar substances present. Consequently, the mixture lends itself to separation on silica gel. The analysis was completed in less than 4 minutes using a short column 3.3 cm long and 4.6 mm in diameter. The silica packing had a particle size of 3 m providing a maximum efficiency of about 5,500 theoretical plates.


Courtesy of Supelco Inc.


Figure 44 The Analysis of Acetaminophen Formulations