Silica‐based monolithic column with evaporative light scattering detector for HPLC analysis of bacosides and apigenin in Bacopa monnieri

A high performance liquid chromatographic method using a silica‐based monolithic column coupled with evaporative light scattering detector (HPLC–ELSD) was developed and validated for simultaneous quantification of bacosides (bacoside A, bacopaside I, bacoside A 3 , bacopaside II, bacopaside X, bacopasaponin C) and apigenin in Bacopa monnieri . The chromatographic resolution was achieved on a Chromolith RP‐18 (100×4.6 mm) column with acetonitrile/water (30:70) as mobile phase in isocratic elution at a flow rate of 0.7 mL/min. The drift tube temperature of the ELSD was set to 95°C, and the nitrogen flow rate was 2.0 SLM (standard liter per minute). The calibration curves revealed a good linear relationship ( r 2 >0.9988) within the test ranges. The detection limits ( S/N = 3) and the quantification limits ( S/N = 10) for the compounds were in the range of 0.54–6.06 and 1.61–18.78 μg/mL, respectively. Satisfactory average recovery was observed in the range of 95.8–99.0%. The method showed good reproducibility for the quantification of these compounds in B. monnieri with intra‐ and inter‐day precision of less than 0.69 and 0.67%, respectively. The validated method was successfully applied to quantify analytes in nine accessions of B. monnieri and thus provides a new basis for overall quality assessment of B. monnieri .