Separation of six beta blockers – atenolol (CAS 29122-68-7), pindolol (CAS 13523-86-9), acebutolol (CAS 37517-30-9), metoprolol (CAS 37350-58-6), labetalol (CAS 36894-69-6) and propranolol (CAS 525-66-6) – on an ASTRA® C18-HE, 5 µm column (150 mm × 4.6 mm, AST-5732-LK46). Gradient elution with A: 20 mM phosphate buffer pH 2.5 and B: ACN, with the flow rate stepped from 0.75 to 1.00 ml/min according to the gradient table, 25 °C, injection volume 2.0 µl, UV detection at 250 nm. All six analytes are resolved between 5.5 and 9.5 minutes.