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An electrochemical fingerprinting method was developed for the quality assessment and geographical origin discrimination of Kadsura coccineafruit. The optimized conditions, using BRBS (pH 5.0) as the electrolyte, a potential range of -0.2 to 1.0 V, and a scan rate of 100 mV/s, yielded reproducible fingerprints with three main oxidation peaks corresponding to phenolic compounds, flavonoids, and lignans. Ethanol was identified as the most effective extraction solvent. The fingerprints exhibited strong correlations (0.8542 to 0.9317) with the contents of key compounds determined by HPLC. Chemometric analysis revealed clear differences among samples from different origins, with accuracies of 96.7%, 96.7%, and 95% for the discrimination of Hubei, Sichuan, and Yunnan samples, respectively. The proposed method demonstrates potential as a rapid, reliable, and cost-effective approach for the quality control and authenticity verification of K. coccineafruit.

We present an experimental study on the photodissociation dynamics of [O2–H2O]+in the 580–266 nm wavelength range using a cryogenic ion trap velocity map imaging spectrometer. The cryogenic ion trap produces mass selected and internally cold [O2−H2O]+ions for photodissociation. By detecting both the O2+and H2O+photofragments using the time-of-flight mass spectrometry and velocity map imaging techniques, branching ratios and total kinetic energy release distributions of the O2++ H2O and H2O++ O2product channels are experimentally measured at 16 different excitation energies. State-resolved photodissociation mechanisms of the parent [O2–H2O]+are interpreted as (1) the O2(X3Σg–) + H2O+(X~2B1), O2(a1Δg) + H2O+(X~2B1), and O2(X3Σg–) + H2O+(A~2A1)channels are produced from direct dissociation of [O2–H2O]+in its excited B~2A″, D~2A″, and F~2A″states, respectively; (2) the O2+(X2Πg) + H2O(X~A11)channel is produced from nonadiabatic relaxations of the excited B~2A″, D~2A″, and F~2A″states to the X~2A″ground state with subsequent dissociation. The latter nonadiabatic processes involve charge-transfer on the potential energy surfaces, and the charge-transfer probabilities are determined from experimental results. The dissociation energy of the ground state to the lowest dissociation limit is experimentally refined as D0= 1.05 ± 0.05 eV. This work provides important information to understand the charge-transfer dynamics in the photochemistry of [O2–H2O]+and in the ion–molecule reaction O2+ H2O+→ O2++ H2O.