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Internal temperature calibration for 1 H NMR spectroscopy studies of blood plasma and other biofluids
Author(s) -
Farrant R. Duncan,
Lindon John C.,
Nicholson Jeremy K.
Publication year - 1994
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1940070508
Subject(s) - chemistry , plasma , blood plasma , analytical chemistry (journal) , proton nmr , spectroscopy , nuclear magnetic resonance spectroscopy , spectrometer , chromatography , biochemistry , organic chemistry , physics , optics , quantum mechanics
Abstract A method for temperature calibration of human blood plasma and cerebrospinal fluid (CSF) samples inside a high resolution NMR spectrometer is presented. This calibration is based on the temperature dependence of the chemical shift difference between the water signal and that from the H‐1 proton of endogenous α‐glucose or, in some circumstances, β‐glucose. This dependence can be fitted using a second‐order polynomial equation and functions for both human blood plasma and human CSF are given. Similar graphs could easily be generated for other fluids. The blood plasma calibration appears to be accurate to ±0.9 K in test samples. The use of the blood plasma calibration graph has also been evaluated using the 1 H NMR spectra of CSF and shown to overestimate the CSF internal temperature by ca 1.3 K. This approach should have a general applicability to blood plasma and CSF samples from normal and pathological situations or from other species, because there are unlikely to be large changes in ionic strength or pH even in disease states. Knowledge of the exact internal temperature of plasma samples is likely to be of particular importance in the investigation of lipid and lipoprotein interactions because of the significant temperature dependence of lipid and lipoprotein NMR linewidths in such samples.