Diffusion measurements with continuous hydrogenation in PHIP

BUSSANDRI, S.; BULJUBASICH, L.; ACOSTA, R.H.

JOURNAL OF MAGNETIC RESONANCE

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2020 vol. 320 p. 106833 - 106840

1090-7807

DOSY is a powerful spectroscopic NMR technique that resolves components in mixtures through the evaluationof different diffusion coefficients. The application of DOSY to dilute mixtures is hampered by thelow signal to noise ratios (SNR), leading to long acquisition times. The use of PHIP may resolve this issueas long as reproducible signals are obtained in order to perform 2D experiments. Here we show that theuse of hollow membranes and adequate gas flow produce constant polarization for a time-span thatenables the acquisition of 2D experiments. A pressure gradient is evidenced by the presence of convection,which is accounted for by using a DPGSE sequence. The influence of J-coupling evolution during thesequence is studied both numerically and experimentally, to determine the optimum echo-time. Theapplicability of the method for samples with poor SNR is explored by setting the reaction rate to achievea low intensity of polarized signals.