INVESTIGATION OF TEMPERATURE DEPENDENCE OF D2O SOLUTIONS BY 400 MHZ NMR

The rate of water proton relaxation of protein solutions were studied in the presence and absence of the paramagnetic ions[gadolinium (III), manganese (II), chromium (III), iron (III), nickel (II), copper (II), and cobalt (II)]   in the previous studies. However, these studies were carried out rather at low frequencies. Therefore, studying of temperature dependence of relaxation rates for absence and presence of 2 % albumin in pure D2O by 400 MHz will be a novelty. In this study, T1 and T2 relaxation ratios of D2O and 0.1 H2O/0.9D2O solutions were investigated with respect to temperature for pure and  for constant  albumin  concentration(2%). The experiments were carried out by using Bruker Avance 400 MHz NMR. Inversion Recovery (180-?-90) pulse step were used for T1, whereas Carr-Purcell-Meiboom-Gill pulse step were used for T2.  The experiments were performed for temperature range of 20°C-40°C by using automatic temperature control unit. 1/T1 and 1/T2 decrease linearly with increasing temperature for pure D2O solutions. However, for 0.1H2O/0.9D2O solutions, the relaxation rates of T1 increase with increasing temperature while T2 decreases with increasing temperature. The decrease in both relaxation rates of the D2O solution with respect to the increased temperature suggests that relaxation is due to spin relaxation interaction. Increasing of relaxation rates with the increasing temperature, in the presence of albumin demonstrates the validity of the dipolar mechanism