Nickel-containing 4,4′-biphenol mixed-mode stationary phase for the separation of polyaromatic compounds, benzene derivatives and nucleotides

Abstract

A new mixed-mode hybrid stationary phase is synthesized, followed by its characterization using BET analysis, SEM, FTIR spectroscopy and EDX analysis. 4, 4′-Biphenol was esterified using ethyl chloroacetate in the presence of potassium carbonate, followed by carboxylation using ethanol/water (9 : 1 v/v%) in the presence of NaOH. The product was treated with nickel nitrate hexahydrate, resulting in the formation of nickel-containing 4,4′-biphenol. The newly synthesized stationary phase was completely characterized through ¹H-NMR, ¹³C-NMR, FTIR, EDX, FE-SEM, BET, particle size distribution, and XRD resulting in characteristics in line with proposed material and best fitting of the material to be used as the new separation media in liquid chromatography. The resultant material was packed in a stainless-steel column (200 mm long × 0.2 mm internal diameter) using a slurry packing machine and tested as a separation media in liquid chromatography. The newly developed column resulted in the separation of different analytes belonging to different classes, such as polyaromatic compounds (PACs), benzene derivatives, and a set of nucleotides, with average plate counts of 272 100, 243 000, and 244 800 plates m⁻¹, respectively, under the optimized mobile phase of acetonitrile/methanol/15 mM ammonium formate in the ratio of 60/30/10 v/v% at pH 6.5 and a flow rate of 25 µL min⁻¹.