title: A Novel Four-step Approach for Systematic Identification of Naphthoquinones in Juglans cathayensis Dode using Various Scan Functions of Liquid Chromatography-Tandem Mass Spectrometry along with Data Mining Strategies.
abstract: BACKGROUND
  Systematic analyses of naphthoquinones in Juglans cathayensis have not yet been reported. It is very challenging to identify naphthoquinones with various structural diversities, especially those at trace levels.
  
  
  OBJECTIVE
  To develop an efficient analytical approach for systematic discovery and identification of naphthoquinones in Juglans cathayensis.
  
  
  METHODS
  A novel four-step approach was evaluated by utilizing various scan functions of liquid chromatography-triple quadrupole-linear ion trap mass spectrometry (LC-QTRAP-MS/MS) and liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (LC-QTOF-MS/MS) along with data mining strategies. First, MS/MS fragmentation behaviors of naphthoquinones were investigated. Second, multiple ion monitoring triggered enhanced product ion scan (MIM-EPI) with specified ions was conducted to identify targeted naphthoquinones. Third, other scan functions of QTRAP-MS/MS and data mining strategies were explored to identify untargeted naphthoquinones. Fourth, structural rationalization and confirmation of naphthoquinones were performed using QTOF-MS/MS via its accurate mass measurement and MS/MS fragmentation functions.
  
  
  RESULTS
  Optimal scan methods and data mining strategies using QTRAP-MS/MS were obtained for identification of targeted and untargeted naphthoquinones. Consequently, 48 naphthoquinones including 24 novel ones were identified or tentatively identified from Juglans cathayensis.
  
  
  CONCLUSIONS
  A novel four-step approach for efficient discovery and identification of naphthoquinones was developed by exploring various scan functions of current LC-MS/MS technologies and data mining strategies, providing an example for systematic characterization of certain classes of phytochemicals, especially trace analytes in complex samples.
authors.affiliation: Tongji School of Pharmacy, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei, 430030, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Gan
authors.affiliation: Department of Pharmacy, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei, 430030, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Tongji School of Pharmacy, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei, 430030, China.
authors.forename: Aiqian
authors.initials: A
authors.lastname: Li
authors.affiliation: Tongji School of Pharmacy, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei, 430030, China.
authors.forename: Chengwu
authors.initials: C
authors.lastname: Song
authors.affiliation: Tongji School of Pharmacy, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei, 430030, China.
authors.forename: Chang
authors.initials: C
authors.lastname: Chen
authors.affiliation: Medical Research Center, Humanwell Healthcare (Group) Co., Ltd, 666 Gao xin Road, Wuhan, Hubei, 430075, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Tongji School of Pharmacy, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei, 430030, China.
authors.forename: Hanli
authors.initials: H
authors.lastname: Ruan
authors.affiliation: Tongji School of Pharmacy, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei, 430030, China.
authors.forename: Hongliang
authors.initials: H
authors.lastname: Jiang
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D057225:Data Mining / Q000379:methods*; D031324:Juglans / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D009285:Naphthoquinones / Q000032:analysis* / Q000737:chemistry
chemical_list: D009285:Naphthoquinones
keywords: Juglans cathayensis Dode; LC-MS/MS; Naphthoquinones; QTOF; QTRAP