An online derivatization strategy targeting carbon–carbon double bonds by laser-ablation carbon fiber ionization mass spectrometry imaging: Unraveling the spatial characteristic in mountain-cultivated ginseng and garden-cultivated ginseng with different ages

•Online derivatization imaging strategy were developed targeting CC in ginseng.•Isotope labelled derivatization promoted by laser ablation carbon fiber ionization.•52 bioactive metabolites were detected in mountain- and garden-cultivated ginseng.•Spatial location differences were found in two ginseng species with various ages.•Mountain-cultivated ginseng held high correlation among bioactive compounds.