Development and validation of a hydrophilic interaction chromatography method coupled with a charged aerosol detector for quantitative analysis of nonchromophoric α-hydroxyamines, organic impurities of metoprolol.

•The first report of a quantitative HPLC method for metoprolol EP impurities M and N.•HILIC method development including a comprehensive HILIC column screening.•The HILIC-CAD method showed good linearity, sensitivity, specificity, accuracy and precision.•Application of a HILIC-CAD method for the analysis of polar, nonochromophoric α-hydroxyamines in metoprolol drug substances and drug products.