Thermodynamic and spectroscopic studies of biotin supplement in aqueous solution of biocompatible choline amino acid ionic liquids

Biotin is one of the most important ingredients of supplements and can be used for some clinical purposes. In this work, aqueous systems of biotin in the presence of biodegradable amino acid-based ionic liquids (ILs), choline glycinate and choline alaninate are investigated. In this respect, the density and speed of sound of the aqueous biotin systems in the different concentrations of the ILs have been measured under atmospheric pressure and T = (288.15–318.15) K. These properties were used to calculate the apparent molar properties of biotin and consequently used to interpret the existing interactions. Also, the UV-vis and FT-IR spectroscopy was used to determine the type of these interactions. According to the results, there are strong interactions between choline glycinate and biotin rather than choline alaninate and the polar–polar interactions between the ILs and biotin are dominant. Also, the strength of these types of interactions has been increased by the addition of biotin and temperature. The spectroscopic studies indicates that strong hydrogen bonding between the biotin and the ILs.