title: Profiling phlorotannins in brown macroalgae by liquid chromatography-high resolution mass spectrometry.
abstract: BACKGROUND
  Phlorotannins, phenolic compounds produced exclusively by Phaeophyceae (brown algae), have recently been associated with a wide variety of beneficial bioactivities. Several studies have measured the total phenolic content in extracts from various species, but little characterisation of individual phlorotannin components has been demonstrated.
  
  
  OBJECTIVE
  The purpose of this study was to develop a liquid chromatography-mass spectrometry (LC-MS) based method for rapid profiling of phlorotannins in brown algae.
  
  
  METHODS
  Phlorotannin-enriched extracts from five phaeophyceaen species were analysed by ultrahigh-pressure liquid chromatography (UHPLC) operating in hydrophilic interaction liquid chromatography (HILIC) mode combined with high resolution mass spectrometry (HRMS). The method was optimised using an extract of Fucus vesiculosus; separation was achieved in less than 15 min. The basic mobile phase enhanced negative-ion electrospray ionisation (ESI), and generated multiply charged ions that allowed detection of high molecular weight phlorotannins.
  
  
  RESULTS
  The phlorotannin profiles of Pelvetia canaliculata, Fucus spiralis, F. vesiculosus, Ascophyllum nodosum and Saccharina longicruris differed significantly. Fucus vesiculosus yielded a high abundance of low molecular weight (< 1200 Da) phlorotannins, while P. canaliculata exhibited a more evenly distributed profile, with moderate degrees of polymerisation ranging from 3 to 49. HRMS enabled the identification of phlorotannins with masses up to 6000 Da using a combination of accurate mass and ¹³C isotopic patterns.
  
  
  CONCLUSIONS
  The UHPLC-HRMS method described was successful in rapidly profiling phlorotannins in brown seaweeds based on their degree of polymerisation. HILIC was demonstrated to be an effective separation mode, particularly for low molecular weight phlorotannins.
authors.affiliation: National Research Council of Canada, Institute for Marine Bioscience, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, Canada.
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Steevensz
authors.forename: Shawna L
authors.initials: SL
authors.lastname: Mackinnon
authors.forename: Rachael
authors.initials: R
authors.lastname: Hankinson
authors.forename: Cheryl
authors.initials: C
authors.lastname: Craft
authors.forename: Solène
authors.initials: S
authors.lastname: Connan
authors.forename: Dagmar B
authors.initials: DB
authors.lastname: Stengel
authors.forename: Jeremy E
authors.initials: JE
authors.lastname: Melanson
mesh_terms: D002247:Carbon Isotopes / Q000737:chemistry; D005591:Chemical Fractionation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000592:standards; D044645:Fucus / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D013058:Mass Spectrometry / Q000379:methods* / Q000592:standards; D008970:Molecular Weight; D010696:Phloroglucinol / Q000737:chemistry* / Q000302:isolation & purification; D058105:Polymerization; D012624:Seaweed / Q000737:chemistry; D013634:Tannins / Q000737:chemistry / Q000302:isolation & purification*; D013997:Time Factors
chemical_list: D002247:Carbon Isotopes; D013634:Tannins; D010696:Phloroglucinol