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Thermal decomposition of copper digallide was studied using experimental (thermal analysis) and theoretical (thermodynamic modeling) methods. The temperatures of CuGa2incongruent melting are in satisfactory agreement between experimental and calculated values. Small differences with the phase diagram can be explained by minor non-stoichiometry of the alloy samples. The experimental studies of thermal diffusivity and thermal expansion of CuGa2were performed in the temperature range 298-500 K. The heat conductivity coefficient was further calculated using literary data concerning the density and heat capacity of the copper digallide.

The determination of antibiotics in food is important due to their negative effect on human health related to antimicrobial resistance problem, renal toxicity, and allergic effects. We propose an impedimetric aptasensor for the determination of kanamycin A (KANA), which was assembled on the glassy carbon electrode by the deposition of carbon black in a chitosan matrix followed by carbodiimide binding of aminated aptamer mixed with oligolactide derivative of thiacalix[4]arene in a cone configuration. The assembling was monitored by cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy. In the presence of the KANA, the charge transfer resistance of the inner interface surprisingly decreased with the analyte concentration within 0.7 and 50 nM (limit of detection 0.3 nM). This was attributed to the partial shielding of the negative charge of the aptamer and of its support, a highly porous 3D structure of the surface layer caused by a macrocyclic core of the carrier. The use of electrostatic assembling in the presence of cationic polyelectrolyte decreased tenfold the detectable concentration of KANA. The aptasensor was successfully tested in the determination of KANA in spiked milk and yogurt with recoveries within 95% and 115%.

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