Chromatographic behaviour of synthetic high pressure high temperature diamond in aqueous normal phase chromatography.

•Non-porous irregular synthetic diamond particles are used in aqueous normal phase chromatography.•Retention mechanism in acetonitrile and methanol based mobile phases is established.•Various buffers effects on the separation selectivity are tested, including alkaline eluents.•A unique selectivity reversal is observed with change acetonitrile/methanol ratio in the eluent.•Weak cation-exchanger could be useful type of phases for aqueous normal phase chromatography.