Determination of 5-hydroxymethylfurfural in a dextrose infusion solution, compared on two ASTRA® columns: ASTRA® C18-HE, 5 µm (150 mm × 4.6 mm, AST-5732-LK46) and ASTRA® DM, 5 µm (150 mm × 4.6 mm, AST-5810-LK46). Isocratic elution with methanol/water 40/60 (v/v) at 1.0 ml/min and 25 °C, injection volume 2.5 µl, UV detection at 284 nm. The polar-embedded ASTRA® DM phase retains the analyte longer (about 2.7 min against 2.4 min on C18-HE), which gives better separation of this polar degradation product from the injection front.