The identification of polyoxyethylene glycols and related compounds by capillary gas chromatography

A sample work-up method for gas chromatographic profiling of polyoxyethylene glycol (PEG)-related compounds in pharmaceutical matrices is described. After a short sample clean-up, carbon-oxygen linkages are partially cleaved with 0.07 M boron tribromide in dichloromethane at room temperature. The reaction is stopped after 1 min by addition of 0.01 M HCl. The products are trimethylsilylated and injected onto a WCOT 50 m x 0.25 mm CP-SIL 5 CB fused silica column. Eleven model compounds, representing four common types of PEG-derivatives, have been evaluated by this method. The results show that characteristic profiles can be obtained from PEG-derivatives carrying different functional groups. Minimum detectable amounts are in the range of 200 micrograms.