Studies of the intercalation and "in vitro" liberation of amino acids in magnesium aluminium layered double, hydroxides

Layered double hydroxides (LDHs) can be structurally described as the stacking of positively charged layers with hydrated anions intercalated in the interlamellar domain. LDHs are a class of materials represented by the general formula: [M1-x2+Mx3+ (OH)(2)]A(x/m)(m-).nH(2)O where: M2+ is a bivalent cation; M3+ is a trivalent cation; A is an anion with m(-) charge. We have studied the intercalation and "in vitro" liberation of aspartic and glutamic amino acids in Mg-Al-LDHs. LDHs intercalated with this type of anions could combine both the compound and the LDH properties. The materials were prepared by the coprecipitation method under constant pH, followed by a hydrothermal treatment for 18 hours, and subsequent characterisation of intercalated materials using PXRD, ATG/DTA and FT-IR. Studies of "in vitro" liberation were made by determination of amino acid concentrations in solution through UV-VIS (nynhydrin methods). Moreover simultaneous pH monitoring was conducted during the experiment.