Abstract Objectives 1 H nuclear magnetic resonance (NMR) spectroscopy is widely applied in large-scale metabolomics studies, often involving biobanking, where pre-analytical conditions critically affect sample quality. Glycerol, a product of in vitro lipolysis, is temperature-sensitive and may serve as an indicator for improper storage. This study aimed to evaluate the analytical performance of NMR-based glycerol quantification in comparison to a classical enzymatic assay and to investigate the influence of storage conditions on glycerol concentrations. Methods Fifty plasma samples from clinical routine were analyzed. Glycerol concentrations were determined using 1 H NMR spectroscopy and an established enzymatic method. To simulate impaired storage conditions, aliquots were stored for three weeks at −80 °C or at room temperature (RT) prior to measurement. Method comparison was performed using correlation analysis, Passing–Bablok regression, and Bland–Altman analysis. Results Glycerol concentrations measured by NMR and the enzymatic assay were highly correlated. Passing–Bablok regression and Bland–Altman analysis indicated a systematic bias between the two methods, which was more pronounced after storage at −80 °C than at RT. Storage at RT resulted in significantly higher glycerol concentrations compared with −80 °C. Conclusions 1 H NMR spectroscopy enables robust and reproducible glycerol quantification in plasma and shows strong correlation with enzymatic measurements, but systematic inter-method bias. The marked temperature-dependent increase in glycerol supports its potential use as an indicator for impaired storage conditions in biobanking and metabolomics research.
Gauß et al. (Sat,) studied this question.