Rapid identification and quantitative analysis of the chemical constituents in Scutellaria indica L. by UHPLC-QTOF-MS and UHPLC-MS/MS.

Ultra high performance liquid chromatography (UHPLC) coupled with a hybrid quadrupole time-of-flight mass spectrometry (QTOF-MS) was used to separate and identify the compounds in Scutellaria indica L. Fragmentation patterns of these compounds were investigated by the UHPLC-QTOF-MS technique in both negative and positive ion modes. By using this strategy, both intact precursors and fragment ions information were obtained from a single injection. A total of 42 phenolic and other compounds were unequivocally or tentatively identified from S. indica for the first time. Among them, 8 phenolic compounds: scutellarin, luteolin, naringenin, wogonoside, apigenin, hispidulin, wogonin and chrysin were further quantified and used as marker substances by multiple-reaction monitoring in negative ionization mode. The results demonstrated that the calibration curves for all analytes showed good linearity (R(2)>0.9992) within the test ranges. The overall limits of detection and limits of quantification were 0.12-10.52 ng/mL and 4.67-20.22 ng/mL, respectively. The recovery was 96.02-102.88% with a relative standard deviation of less than 3.02%. It is proposed that the methods described here can be applied for rapid evaluation, quality control and authenticity establishment of S. indica.