Growth of C₁₂E₈Micelles with Increasing Temperature. A Convection-Compensated PGSE NMR Study

Assessment of diffusion coefficients of general solvents by PFG-NMR: Investigation of the sources error

“…This result could be caused by the effect of the convection of the solvent. The existence of convection effects was confirmed by measuring the diffusion coefficient with increasing D [51,56]. When we measured the self-diffusion coefficients of benzene for D set to 50 and 100 ms, the observed difference for those two D was almost 0.4% when using the Shigemi NMR tube.…”

Sensitive and robust electrophoretic NMR: Instrumentation and experiments

“…(Also note that the generation of a thermal gradient during the course of an experiment is intrinsic to eNMR. Also, the thermal gradient in eNMR is dominantly radial in contrast to the typically vertical temperature gradients which often arise outside the ambient temperature range in temperature-regulated magnetic field gradient probes [35,36] and plague PGSE-type NMR self-diffusion measurements. )…”

Low Temperature 1H‐, 19F‐, and 31P‐PGSE Diffusion Measurements. Applications to Cationic Alcohol Complexes

“…2 For a given sample with a particular set of properties (viscosity, thermal diffusivity, thermal expansion coefficient), convection appears when the temperature gradient within the solution exceeds a certain level [23] [24] [29]. It is known that, for cylindrical samples (e.g., in NMR tubes), this value is inversely proportional to the fourth power of the radius of the sample tube [24]. Thus, the obvious way to suppress convection artifacts seems to be to use narrower sample tubes, and this is the approach that we have taken.…”

“…Nonlinearity occurs only when the effect of convection dominates relative to diffusion [24]. Thus, it may happen that linear plots of ln(I/I o ) vs.…”

“…All data leading to the reported D values afforded lines with correlation coefficients > 0.999. Jerschow et al [24] have suggested the use of a double stimulated echo (DSTE) pulse sequence to eliminate convection artifacts, and successfully applied this method at high temp. (although they state that its utility is limited to convection currents with a constant laminar-flow profile during the diffusion interval, and that it does not compensate turbulent convection).…”