The DOSY Toolbox: A new tool for processing PFG NMR diffusion data

The application of high resolution diffusion NMR to the analysis of manuka honey

“…Recent improvements in high-resolution NMR instrumentation, coupled with the exceptional work conducted in the improvement of flexible processing software has made DOSY NMR an increasingly valuable tool in complex mixture analysis (Nilsson, 2009;Nilsson, Duarte, Almeida, Delgadillo, & Goodfellow, 2004;Nilsson et al, 1997). Whilst developments in mass spectrometry (MS n ) have yielded a better understanding of a range of previously poorly characterised mixtures, the rapid analysis of honeys, for example, has been limited by the necessity for either SPE or liquid phase extraction prior to analysis (Drynan, Clifford, Obuchowicz, & Kuhnert, 2010;Gomez-Caravaca, Gomez-Romero, Arraez-Roman, Segura-Curretero, & Fernandez-Gutierriz, 2006;Sanchez-Rabaneda et al, 2004).…”

High resolution 13C DOSY: The DEPTSE experiment

“…13 C DEPTSE measurements were carried out using 10 gradient amplitudes ranging from 6 to 54 G cm À1 in equal steps of gradient squared, 1024 transients, 65,536 complex data points, a pulse flip angle h of 45°, a diffusion-encoding gradient pulse duration of 6.0 ms, and a diffusion time of 0.05 s, in a total time of 43 h. Oneshot-INEPT [25,56] measurements were carried out using 10 gradient amplitudes ranging from 6 to 54 G cm À1 in equal steps of gradient squared, 1024 transients, 65,536 complex data points, a refocusing delay of 1/(4 1 J CH ) (equivalent to a pulse flip angle h of 45°in DEPT), a diffusion-encoding gradient pulse duration of 1.4 ms, and a diffusion time of 0.05 s, in a total time of 43 h. All spectra were manually phase corrected, and either Fourier transformed with 1 Hz Lorentzian line broadening to minimize the effect of any variation in lineshape between spectra while avoiding excessive loss of resolution, or in the case of 1 H DOSY, reference deconvoluted [57] to a line width of 1 Hz. All data processing was carried out using the DOSY Toolbox [58].…”

Matrix-assisted diffusion-ordered spectroscopy

“…Of these, a DOSY spectrum, where the chemical shifts and diffusion coefficients are arranged in a two dimensional presentation, is the most visual and immediate way of showing this information. Software for the processing of this data in this manner is supplied by all major NMR manufacturers and stand-alone software is also available 15 . A DOSY spectrum is used in a semi-quantitative manner, separating out the components of a mixture according to their respective diffusion coefficients.…”