title: A simplified determination of total concentrations of Ca, Fe, Mg and Mn in addition to their bioaccessible fraction in popular instant coffee brews.
abstract: A direct analysis of instant coffee brews with HR-CS-FAAS spectrometry to determine the total Ca, Fe, Mg and Mn content has been developed and validated. The proposed method is simple and fast; it delivers good analytical performance; its accuracy being within -3% to 3%, its precision--2-3% and detection limits--0.03, 0.04, 0.004 and 0.01 mg l(-1) for Ca, Fe, Mg and Mn, respectively. In addition, Ca, Fe, Mg and Mn bioaccessibility in instant coffee brews was measured by means of the in vitro gastrointestinal digestion with the use of simulated gastric and intestinal juice solutions. Absorption of metals in intestinal villi was simulated by means of ultrafiltration over semi-permeable membrane with a molecular weight cut-off of 5 kDa. Ca, Fe, Mg and Mn concentrations in permeates of instant coffee gastrointestinal incubates were measured with HR-CS-FAA spectrometry.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Wroclaw University of Technology, Smoluchowskiego 23, 50-372 Wroclaw, Poland.
authors.forename: Ewelina
authors.initials: E
authors.lastname: Stelmach
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Wroclaw University of Technology, Smoluchowskiego 23, 50-372 Wroclaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Szymczycha-Madeja
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Wroclaw University of Technology, Smoluchowskiego 23, 50-372 Wroclaw, Poland. Electronic address: pawel.pohl@pwr.wroc.pl.
authors.forename: Pawel
authors.initials: P
authors.lastname: Pohl
mesh_terms: D002118:Calcium / Q000032:analysis*; D040503:Coffea / Q000737:chemistry*; D003069:Coffee / Q000737:chemistry*; D007501:Iron / Q000032:analysis*; D008274:Magnesium / Q000032:analysis*; D008345:Manganese / Q000032:analysis*; D008670:Metals / Q000032:analysis; D013054:Spectrophotometry, Atomic / Q000379:methods
chemical_list: D003069:Coffee; D008670:Metals; D008345:Manganese; D007501:Iron; D008274:Magnesium; D002118:Calcium
keywords: Calcium; Direct analysis; Flame atomic absorption spectrometry; In vitro gastrointestinal digestion; Instant coffee; Iron; Magnesium; Manganese