Figure 2.

Principal component analysis (PCA) score plots of green tea samples drawn with Hotelling's 95% confidence ellipse for (A) untargeted UPLC-MS, (B) targeted quantitative UPLC-MS, and (C) Untargeted ¹HNMR. Data points representing triplicate green tea samples were closely clustered, and distinct clusters were observed between green tea supplements (denoted as Suppl), green teas (leaf and powder), and the negative control (turmeric-ginger T23 denoted as non-green tea). Representative samples are highlighted, including NIST SRM 3254 (T26), SRM 3255 (T27), and SRM 3256 (T37), to demonstrate the reproducibility of the extraction and analytical protocol. Adapted with permission from Kellogg et al. (83); further permissions related to this excerpted material should be directed to the American Chemical Society.