Observation of Triplet Traces Obtained with Inversion Recovery Method in Both Residual Water- and H2O/D2O-Albumin Mixture by Using 400 MHz Proton NMR

Abstract

NMR studies involving H₂O/D₂O mixtures are mainly based on a single spectrum of water. However, some recent papers have revealed the presence of an HDO triplet in H₂O/D₂O, which is caused by the splittings of H₂O signal by deuterium (D). Observation of inversion recovery (IR) traces of this triplet should be very useful for analyzing relaxation data in such mixtures. In this work, in order to obtain the traces, inversion recovery signal intensities of residual water and a mixture of 0.10 H₂O and 0.90 D₂O were acquired versus a set of short delay times in the presence or absense of 0.2 g albumin. T₁ and T₂ curves of the same samples were also obtained by using different sets of much longer times for checking the effect of radiation damping on the traces. Experiments were carried out with a 400 MHz proton NMR spectrometer equipped with a topspin programme for relaxation measurements. Inversion recovery data of the traces and T₁ curves were obtained with the inversion recovery method, while T₂ curves were obtained with the Carr-Purcell-Meiboom-Gill method. Data was processed through an analysis programme of the topspin. Data showed that radiation damping is effectively reduced upon addition of albumin. Furthermore, the data of the residual water- and the mixture with albumin demonstrated the traces of the triplet at the initial part of a single inversion recovery line. Our results suggest that the splitting of water proton signal by deuterium can be detectable by the inversion recovery method for D₂O- and the mixture containing albumin.