Abstract:

This study aimed to explore a robust method for propolis authentication. Ultra high performance liquid
chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) first grade cation electronic spray
ionization ([M+H]+) total ion chromatogram (TIC) and mass spectrometry (MS) were used to acquire and analyze
chromatographic fingerprints and mass spectral fingerprints of hot 75% (V/V) ethanol extracts of 9 propolis samples. Samples
of two brands of propolis from Guangdong province were identified as abnormal or fake propolis by TIC fingerprint profile;
neither rutin nor quercetin was found in all 9 samples. Compared to HPLC chromatographic fingerprint profiling, TIC profile
combined with m/z ratio of molecules in the peak could improve the discrimination power of chromatographic fingerprint
profiling. Through principal component analysis (PCA) of mass spectral fingerprint two abnormal propolis samples were
confirmed. This study implies that the combination of the two strategies may be helpful to develop a more accurate method
for propolis authentication. Mass spectrum contains far more information which is more complicated when compare to
chromatogram, so that deserving to be further explored.

Key words: propolis, ultra high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLCQTOF-MS), chromatographic fingerprint profiling, mass spectrum fingerprint profiling, principal component analysis (PCA)