Polyethyleneimine Functionalized Multi-walled Carbon Nanotubes-Based Solid Phase Extraction for Selective Screening of Carboxylic Acid Compounds in Natural Products

In this work, by adopting polyethyleneimine functionalized multi-walled carbon nanotubes as the absorbent, a solid phase extraction based method for fast and selective screening of carboxylic acid compounds was developed. The structure and morphology of the polyethyleneimine functionalized multi-walled carbon nanotubes were confirmed via scanning electron micrograph, transmission electron microscopy, Fourier transform infrared spectra and X-ray photoelectron spectroscopy. And the proposed approach was successfully applied to screen carboxylic compounds from the crude extract of Perilla frutescens . As a result, seven polyhydric compounds with carboxyl including caffeic acid, luteolin-7- O -diglucuronide, apigenin-7- O -diglucuronide, sagerinic acid, scutellarein-7- O -glucuronide, rosmarinic acid, and apigenin-7- O -glucuronide were favorably screened out from compounds without carboxyl group. Similar screening results were also obtained via generalizing the method to the crude extract of Chrysanthemum . This strategy could serve as a rapid and efficient pathway for preliminary screening of certain types of compounds from complex natural products.