Dispersive solid‐phase extraction of alkaloids and polyphenols using borate hypercrosslinked polymers

Abstract

In this study, a borate hyper‐crosslinked polymer was synthesized by crosslinking 1‐naphthalene boric acid and dimethoxymethane via the Friedel‐Crafts reaction. The prepared polymer exhibits excellent adsorption performance toward alkaloids and polyphenols with maximum adsorption capacities ranging from 25.07 to 39.60 mg/g. Adsorption kinetics and isotherms model results indicated the adsorption was a monolayer and chemical process. Under the optimal extraction conditions, a sensitive method was established for the simultaneous quantification of alkaloids and polyphenols in green tea and Coptis chinensis by coupling with the proposed sorbent and ultra‐high performance liquid chromatography detection. The proposed method exhibited a wide linear range of 5.0–5000.0 ng/ml with R2 ≥ 0.99, a low limit of detection (0.66–11.25 ng/ml), and satisfactory recoveries (81.2%–117.4%). This work provides a simple and convenient candidate for the sensitive determination of alkaloids and polyphenols in green tea and complex herbal products.