title: Extraction of Al, Cu, Fe, Mn, Ni and Zn--polyphenol complexes from black tea infusions by Amberlite resins.
abstract: BACKGROUND
  Metals can be present in tea infusion as ions or as complexes with endogenous bioligands naturally occurring in tea, especially with polyphenols. Their chemical form, i.e. free or metal complexes, can affect their actual bioavailability, gastrointestinal absorption and possible toxicity.
  
  
  RESULTS
  The total amount of Al, Cu, Fe, Mn, Ni and Zn in black tea infusions was determined by inductively coupled plasma--atomic emission spectroscopy after mineralization and compared with their fractions occurring as polyphenol complexes, extracted using two different polymeric resins: Amberlite XAD-2 and Amberlite XAD-7.
  
  
  CONCLUSIONS
  The obtained results demonstrated the suitability of Amberlite resins for the extraction of Al, Cu, Fe, Mn, Ni and Zn–polyphenol complexes from black tea infusions and for the evaluation of the actual distribution of the considered metals among different chemical species, i.e. as free metals and as polyphenol complexes.
authors.forename: Claudio
authors.initials: C
authors.lastname: Mucchino
authors.forename: Marilena
authors.initials: M
authors.lastname: Musci
mesh_terms: D000180:Acrylic Resins; D001682:Biological Availability; D028241:Camellia sinensis / Q000737:chemistry*; D004781:Environmental Exposure / Q000032:analysis; D006801:Humans; D007408:Intestinal Absorption; D008024:Ligands; D019216:Metals, Heavy / Q000032:analysis*; D059808:Polyphenols; D011137:Polystyrenes; D012117:Resins, Synthetic; D013662:Tea / Q000737:chemistry*; D014131:Trace Elements / Q000032:analysis*
chemical_list: D000180:Acrylic Resins; D008024:Ligands; D019216:Metals, Heavy; D059808:Polyphenols; D011137:Polystyrenes; D012117:Resins, Synthetic; D013662:Tea; D014131:Trace Elements; C015661:amberlite XAD 7; C003771:Amberlite XAD-2 resin; C046797:amberlite