Use of Hydrophilic Interaction Liquid Chromatography to Separate Butylhydroxyanisole Isomers

The possibility of using columns with nitrile, diol, and amino sorbents to separate butylhydroxyanisole isomers by hydrophilic interaction liquid chromatography was studied. Columns containing nitrile and diol sorbents did not separate butylhydroxyanisole isomers using either hydrophilic interaction liquid chromatography or reverse phase chromatography. Separation of butylhydroxyanisole isomers by reverse phase chromatography was only obtained on a Diasphere 110 C10CN 250 × 4.6 mm, 5 μm column using acetonitrile:water (50:50) or methanol:water (65:35) as the mobile phase. These isomers could only be separated by hydrophilic interaction chromatography on columns containing an amino sorbent when the acetonitrile level in the mobile phase was greater than 97%. Columns containing amino sorbents had greater selectivity for butylhydroxyanisole isomers than columns containing C18 sorbents in reverse phase chromatography. Better isomer separation was obtained on Zorbax NH₂150 × 4.6 mm, 5 μm columns with a mobile phase acetonitrile content of 99 – 99.5%.