Polymeric stationary phases based on poly(butylene terephthalate)and poly(4-vinylpirydine) in the analysis of polyphenols usingsupercritical fluid chromatography. Application to bee pollen

Abstract

Two new polymer-based stationary phases; DCpak PBT (poly(butylene terephthalate)) and DCpak P4VP(poly(4-vinylpirydine)) were evaluated for the analysis of polyphenols using supercritical fluid chro-matography (SFC). The compounds studied included phenolic acids and flavonoids. The different variablesthat influence the chromatographic separation, such as type and percentage of organic modifier, additive,pressure and temperature were examined. Using the DCpak P4VP column the retention was exception-ally high, obtaining better results with the DCpak PBT column. The separation of nine polyphenols wasachieved using a gradient of modifier (methanol with 0.1% trifluoroacetic acid) from 5 to 50%, a pressureof 150 bar, a temperature of 35◦C and a flow-rate of 2 mL/min. The use of additives was necessary in orderto obtain good peak shapes and efficiencies, achieving the best results with trifluoroacetic acid. LODs andLOQs values were lower than 5 g/mL in all the cases; meanwhile, the %RSD values for method repeatabil-ity and inter-day reproducibility were lower than 3% and 10% respectively. Finally, the proposed methodwas successfully applied to the analysis of polyphenols in commercial bee pollen; four compounds,namely cinnamic acid, p-coumaric acid, catechin and quercetin were identified and quantified.