Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) based inorganic element fingerprinting and multivariate analysis for discriminating the geographical origin of domestic and imported dried Platycodon roots

초록

Geographical origin authentication of dried Platycodon grandiflorum roots is important for preventing false labeling and supporting the quality control of commercially distributed food and medicinal plant materials. In this study, inorganic elemental fingerprints of domestic and imported dried P. grandiflorum roots were fingerprinted using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). A total of 114 samples, including 58 domestic and 56 imported samples, were ground, sieved, and pelletized prior to analysis. Twentyfive inorganic elements were monitored, and the resulting signals were expressed as counts per second (CPS) and used as relative elemental fingerprints rather than absolute total elemental concentrations. The elemental fingerprints showed origin-dependent differences between domestic and imported samples. Several elements, including Ca, Ti, Zn, Ga, Sr, and Zr, showed relatively higher signal intensities in imported samples, whereas Cr, Mn, and Se tended to be higher in domestic samples. These differences indicate that inorganic elemental fingerprints can provide useful chemical information for distinguishing the geographical origin of dried P. grandiflorum roots. Multivariate analyses were used to support the discrimination performance of the elemental fingerprints. The OPLS-DA model showed good explanatory and predictive performance (R-2 = 0.848, Q(2) = 0.806), and ROC analysis yielded an AUC of 1.000 within the model development dataset. LDA further achieved a fivefold cross-validation accuracy of 97.4 +/- 2.4% and 100.0% accuracy in an independent external validation set. These results demonstrate that LA-ICP-MS-based inorganic elemental fingerprinting can serve as a rapid and reliable approach for geographical origin verification of dried P. grandiflorum roots. The proposed strategy may also be useful for authenticity control of other dried agricultural and medicinal plant materials.

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