NMR‐invisible lactate in blood plasma

Abstract
Resonances for lactate are broadened in 500 MHz 1H NMR spectra of human blood plasma and only about one‐third is visible in Hahn spin‐echo spectra. Similar effects are observed for some other carboxylate anions. Lactate added to the high‐M r fraction of plasma can give rise to peaks which are too broad to observe in either single‐pulse or spin‐echo spectra. Addition of agents such as NH4Cl of SDS dramatically increases the intensities of lactate peaks. Some glycoproteins appear to broaden lactate resonances.