Green synthesis of a urea-melamine-hexamethylenetetramine resin for efficient extraction and determination of berberine hydrochloride in Pudilan antiphlogistic oral liquid.

A urea-melamine-hexamethylenetetramine resin (UMHR) was synthesized using water as the reaction medium, with hexamethylenetetramine serving as an environmentally friendly crosslinking agent in place of traditional formaldehyde. The resin was optimized as an efficient solid-phase extraction (SPE) adsorbent through optimization of synthetic parameters. A precise detection method for berberine hydrochloride in Pudilan antiphlogistic oral liquid was established by optimizing extraction parameters. The method exhibited excellent linearity, with a correlation coefficient (r ≥ 0.9998) over a concentration range of 0.40-100.0 μg/mL. The limits of detection (LOD) and quantitation (LOQ) were 0.094 μg/mL and 0.314 μg/ mL, respectively. Recoveries ranged from 87.9 % to 97.3 %, with relative standard deviations (RSDs) below 3.2 %. This study presents a novel and environmentally friendly analytical approach for the quality control of traditional Chinese medicine preparations.