Polyaniline based material as a new SPE sorbent for pre-treatment of Chelidonium majus extracts before chromatographic analysis of alkaloids

Abstract

In the present study, deprotonated and protonated polyaniline based sorbent obtained by in situ polymerization of aniline on silica (Si-PANI) was applied for SPE pretreatment of Chelidonium majus extracts before determination of benzophenanthridine, protoberberine and protopine alkaloids. The experimentally optimized conditions, such as protonated polyaniline impregnated with methanol as a sorbent, 2 mL of water and methanol mixture (1/1, v/v) as a washing solution, and 5 mL of 0.1 M methanolic solution of ammonia as an elution solvent, yielded the highest values of analyte recovery (above 96.5%) with simultaneous removal of undesirable plant matrix. Virtually modeled structure of polyaniline revealed possible occurrence of the mixed mode binding mechanism, based both on π-π and ion interactions on protonated form of polyaniline. Moreover, lack of significant changes of the polyaniline film quality assessed by Raman spectroscopy after series of ten experiments proved the reusability of the sorbent.

Keywords: Alkaloids; Chelidonium majus L.; Raman spectroscopy; Silica modified with polyaniline; Solid phase extraction.