title: Accurate determination of reference materials and natural isolates by means of quantitative (1)h NMR spectroscopy.
abstract: A fast and precise proton nuclear magnetic resonance (qHNMR) method for the quantitative determination of low molecular weight target molecules in reference materials and natural isolates has been validated using ERETIC 2 (Electronic REference To access In vivo Concentrations) based on the PULCON (PULse length based CONcentration determination) methodology and compared to the gravimetric results. Using an Avance III NMR spectrometer (400 MHz) equipped with a broad band observe (BBO) probe, the qHNMR method was validated by determining its linearity, range, precision, and accuracy as well as robustness and limit of quantitation. The linearity of the method was assessed by measuring samples of l-tyrosine, caffeine, or benzoic acid in a concentration range between 0.3 and 16.5 mmol/L (r(2) ≥ 0.99), whereas the interday and intraday precisions were found to be ≤2%. The recovery of a range of reference compounds was ≥98.5%, thus demonstrating the qHNMR method as a precise tool for the rapid quantitation (~15 min) of food-related target compounds in reference materials and natural isolates such as nucleotides, polyphenols, or cyclic peptides.
authors.affiliation: Chair of Food Chemistry and Molecular Sensory Science, Technische Universität München , Lise-Meitner-Strasse 34, D-85354 Freising-Weihenstephan, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Frank
authors.forename: Johanna Karoline
authors.initials: JK
authors.lastname: Kreissl
authors.forename: Andreas
authors.initials: A
authors.lastname: Daschner
authors.forename: Thomas
authors.initials: T
authors.lastname: Hofmann
mesh_terms: D019817:Benzoic Acid / Q000032:analysis; D002110:Caffeine / Q000032:analysis; D005504:Food Analysis / Q000379:methods / Q000592:standards*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000592:standards*; D012015:Reference Standards; D014443:Tyrosine / Q000032:analysis
chemical_list: D002110:Caffeine; D014443:Tyrosine; D019817:Benzoic Acid