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. [ABSTRACT FROM AUTHOR]