Solid state NMR and extraction studies on “phenyl”-bonded stationary phases used for solid phase extraction

Abstract

The solid phase extraction (SPE) and elution of [ 14C]-propranolol from aqueous buffer has been studied for a range of phenyl-bonded SPE materials. Differences were noted in the recovery of the analyte using methanol-water eluents depending upon the manufacturer and whether or not phase had been endcapped. Efficient recoveries of [ 14C]-propranolol were only achieved when triethylamine was added to the eluting solvent as a competing base. Solid state cross polarisation/magic angle spinning (CP/MAS) NMR spectroscopy was used to characterise the phases further, which revealed differences in endcapping between materials as well as differences in the type and extent of cross-linking.