Fig. 2

Discriminant Analysis of Partial Least Squares. A: Positive ion mode (a) D vs Q PLS-DA obtained dispersion plot and sequence verification diagram (b) Z vs D PLS-DA obtained dispersion plot and sequence verification diagram (c) Z vs Q PLS-DA obtained dispersion Point graph and sorting verification graph. B: Negative ion mode (a) D vs Q PLS-DA obtained dispersion point diagram and sequence verification diagram (b) Z vs D PLS-DA obtained dispersion point diagram and sequence validation diagram (c) Z vs Q PLS-DA obtained dispersion point graph and sorting verification graph. Scatter plot of scores, the horizontal coordinate is the score of the sample on the first principal component; the vertical coordinate is the score of the sample on the second principal component; R2Y indicates the explanatory rate of the model, Q2Y is used to evaluate the predictive power of the PLS-DA model, and R2Y is greater than Q2Y indicates a well established model. For the ranking test, the horizontal coordinates represent the correlation between the randomly grouped Y and the original grouped Y, and the vertical coordinates represent the scores of R2 and Q2. (“D” refer to Artemisia sieversiana. “Q” refer to Artemisia annua. “Z” refer to Artemisia wellbyi)