Fig. 2. A region of a lobster abdominal muscle ¹H-spectrum. The peaks for betaine, arginine/arginine phosphate (at 1.95 p.p.m.) and -CH₂/-CH groups yielded linear attenuation plots and sufficient signal-to-noise ratios to allow measurement of D at several diffusion times. Alanine and lactate methyl peaks are also indicated for reference, although diffusion of these metabolites was not examined in the present study.