Characteristics of a Lorentzian to Gaussian transformation function as a weighting function in processing the two-dimensional nuclear magnetic resonance spectrum of a drug-phosphatidylcholine vesicles solution.

Abstract

Advantages and disadvantages of a Lorentzian to Gaussian trans formation function, which has been commonly employed in enhancing the resolution of two-timensional nuclear magnetic resonance (2D NMR) spectra, were investigated by applying this function to the 2D nuclear Overhauser effect (NOE) NMR spectrum of a drug-phosphatidylcholine vesicles solution. It was found that, although this function is known to be useful in enhancing the resolution of an NMR spectrum of a low-molecular-weight molecule which can afford relatively narrow NMR resonance peaks, the function often fails to yield a good line shape or contour map in the case where there exist broad resonance peaks having various line widths as in the presently tested sample solution. A careful choice of the parameters relevant to the function is required. In conclusion, the Lorentzian to Gaussian transformation function is less superior to a sine-bell function which has also been employed as an alternative function to process 2D NMR spectra. Some examples are presented in this paper.