Determination of choline in erythrocytes using high-resolution proton nuclear magnetic resonance spectroscopy: comparison with a choline oxidase method.

Detailed operating conditions are reported for the determination of choline in human erythrocytes using proton nuclear magnetic resonance spectroscopy in conjunction with the inversion-recovery spin-echo pulse sequence. The results of the NMR method were in excellent agreement with those obtained using an enzymatic (choline oxidase) assay; however, they were approximately three times higher than those reported using gas chromatography/mass spectrometry techniques. The differences may be partly due to the method of preparing or sampling cells since there is a distribution of choline in cells of different ages. However, choline levels were not affected by the methods used in the present study for storing or preparing cells.