HPTLC-bioautography/SERS screening nifedipine adulteration in food supplement based on Ginkgo biloba

Ginkgo biloba was a popular phytomedicine as the essential ingredient of many food supplement. In this work, a bio-inspired HPTLC method was proposed for the visualized screening of nifedipine adulteration in food supplement based on Gingko biloba . To customize the visualization of the analyte by inhibiting bacterium ( Photobacterium phosphoreum ) bioluminescence, the silica gel plate that gives the highest detectability was selected as the stationary phase of separation. Thereafter, the HPTLC procedure (toluene and ethyl acetate 8/2, v/v, as the mobile phase, to a distance of 60 mm) was optimized and standardized as a sample cleanup tool to exclude noises caused by bioactive co-extracts. Then, the separation result fixed on the plate layer was selectively visualized as dark bands against the white background, only after 6 min exposure. To achieve quantitation of the obtained HPTLC images, an enhanced quantitative analysis was optimized via software (ImageJ) facilitated pixel scanning, offered remarkable sensitivity (LOD=24.0 μg/g), linearity ( R 2 =0.9985 within 50–300 ng/band) and precision (RSD<7.2%). Further, the developed method was validated with real samples (recovery rates within 81.0–92.8%). In conjunction with image quantitation, in-situ surface enhance Raman spectroscopy was incorporated into the analysis, using silver nanoparticles as the active substrate and He:Ne 633 nm lamp the incident laser source. The obtained SERS spectra displayed highly characteristic fingerprint patterns, enabling unambiguous confirmation of effect-directed results.