Microfluidic evaporative light scattering detector coupled with capillary liquid chromatography and its application to Ginkgo biloba extract analysis

A novel separation system of microfluidic evaporative light scattering detector (microELSD) coupled with capillary liquid chromatography (cLC) was built and applied to the separation and detection of herbal medicine Ginkgo biloba extract and its disperse tablet formulation. Compared with the traditional HPLC, this microELSD-cLC system consumed much less sample and solvent. Some key parameters were optimized. It was found that the higher the evaporization temperature of the drift tube, the higher S/N could be achieved. The mobile phase A was 0.05% (v/v) trifluoroacetic acid (TFA), and the mobile phase B was methanol containing 0.05% (v/v) TFA. The optimized gradient conditions were as follows: 0-10 min, 5% B - 25% B; 10-25 min, 25% B - 38% B; 25-35 min, 38% B; 35-40 min, 38% B - 42% B; 40-55 min, 42% B - 50% B. The complex herbal medicine Ginkgo biloba extract and its disperse tablet formulation were successfully separated. Four main therapeutic components (bilobalide and ginkgolide A, B, C) were finally separated and determined, which were terpene lactones with pretty weak UV absorption. The RSDs of the detected terpene lactones from different manufacturers were all no more than 2.42%, which proved this platform's good analysis repeatability. The results showed the applicability of the platform to the analysis of complex traditional Chinese medicines.