Journal of the Brazilian Chemical Society
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/13322
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Item Development of a Disposable Pipette Extraction Method Using Coffee Silverskin as an Adsorbent for Chromium Determination in Wastewater Samples by Solid Phase Extraction(Sociedade Brasileira de Química, 2022-05-02) Silva, Weida R.; Costa, Bruno E. S.; Batista, Alex D.; Alves, Vanessa N.; Coelho, Nivia M. M.A procedure using disposable pipette tips adapted for solid-phase extraction, known as DPX SPE, was used as an alternative way for the chromium determination in wastewater samples. DPX-SPE consists of a device which allows a dynamic contact between the sample and the solid-phase. A residue obtained from the processing of coffee beans, denominate coffee silverskin, was used as a new adsorbent. Characterization techniques revealed properties of lignocellulosic materials with potential application for chromium adsorption. The parameters including adsorbent mass (25.00 mg), elution solvent (0.1 mol L-1 HCl, 200 μL) and pH (2.0) were optimized. Thus, 1.00 mL of deionized water for conditioning, 4.00 mL of sample, 2 extraction cycles and 1 elution cycle were the employed conditions. Enrichment factor of 12, limit of detection of 6.00 µg L-1 and relative standard deviation (RSD) 1.3% (n = 3) were obtained. The method proved to be fast, cheap, environmentally friendly, and simple, providing good recoveries (104-113%), and it was satisfactorily applied in real samples.Item Evaluation of the bioaccessability of Ca, Fe, Mg and Mn in ground coffee infusions by in vitro gastrointestinal digestion(Sociedade Brasileira de Química, 2014) Stelmach, Ewelina; Pohl, Pawel; Szymczycha-Madeja, AnnaThe bioaccessibility of Ca, Mg, Mn and Fe in ground coffee brews was assessed through in vitro gastrointestinal digestion with stomach and intestinal juice solutions (pepsin, pancreatin and bile salts). Absorption of metals in the intestinal villi was simulated by ultrafiltration over a 3 kDa molecular weight cut-off semi-permeable membrane. Concentrations of Ca, Fe, Mg and Mn in coffee infusions and permeates of gastrointestinal incubates were measured by flame atomic absorption spectrometry. It was established that Mg, with a 62% contribution to the bioaccessible fraction, was the most bioaccessible. The bioaccessibilities of Ca (42%) and Fe (43%) were similar but individual results for both metals varied widely. The least bioaccessible metal was Mn, with an average contribution of 27%. Drinking one cup of coffee daily covers dietary reference intakes of Ca, Fe, Mg and Mn to a small degree (less than 3%).