Validation of an HPLC-RI method for the quantification of D-pinitol from Mesembryanthemum crystallinum

Abstract

A high-performance liquid chromatography with refractive index detection (HPLC-RI) method was developed and validated to quantify D-pinitol in Mesembryanthemum crystallinum. Effective separation was achieved with a retention time of 8.7 min. The proposed method demonstrated excellent linearity (r²= 0.9999) over a 0.125-2 mg/mL range, with a calibration curve equation of Y = 102.37X-181.97. The limits of detection and quantification were 19.2 and 58.2 µg/mL, respectively. Accuracy, assessed by recovery tests at three spiked concentrations, showed recovery rates between 103.24 and 112.69% with relative standard deviations (RSDs) ranging from 0.84 to 4.19%. Precision analyses revealed intra-and inter-day RSDs of 0.77 and 1.26%, respectively, at a concentration of 20.0 mg/mL. This study presents the first validated HPLC-RI method for D-pinitol quantification in M. crystallinum, providing a reliable and cost-effective analytical tool that fills a gap in existing research, as well as a methodological basis for future pharmacological and phytochemical studies.