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Rapid assessment of the illegal presence of 1,3‐dimethylamylamine (DMAA) in sports nutrition and dietary supplements using 1 H NMR spectroscopy
Author(s) -
Monakhova Yulia B.,
Ilse Maren,
Hengen Julia,
elAtma Oliver,
Kuballa Thomas,
KohlHimmelseher Matthias,
Lachenmeier Dirk W.
Publication year - 2014
Publication title -
drug testing and analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.065
H-Index - 54
eISSN - 1942-7611
pISSN - 1942-7603
DOI - 10.1002/dta.1677
Subject(s) - chemistry , detection limit , food and drug administration , chromatography , calibration curve , ingredient , sample preparation , analytical chemistry (journal) , food science , medicine , environmental health
1,3‐Dimethylamylamine (DMAA) is a stimulant that can be found in pre‐workout sports nutrition and dietary supplements. This practice is illegal because DMAA is not a safe food ingredient but rather an unapproved medicinal compound due to its pharmacological action. In order to determine the DMAA content in such products, a nuclear magnetic resonance (NMR) spectroscopic method was developed and validated (DMAA was quantified as DMAA‐HCl). For quantification, the collective integral from two of the methyl groups of the molecule in the range δ 0.92–0.84 ppm was used. The method was linear over the examined range of 1–21 g/kg (R 2 = 0.9937). The recoveries from spiked concentrations (0.1–6 g/kg) ranged between 85% and 105% (96% on average), with a relative standard deviation (RSD) of 1% for an authentic sample. The detection limit was 0.03 g/kg and the quantification limit was 0.08 g/kg (calculated for 75 mg sample weight). The actual DMAA‐HCl content in the sample was quantified using calibration curves (external standardization) or 3,5‐dinitrobenzoic acid as single‐point internal standard. The developed NMR methodology was applied for the analysis of 16 products, from which 9 samples were found positive (the DMAA‐HCl concentration varied between 3.1 g/kg and 415 g/kg). The method can be recommended for routine use in food testing, customs or doping control laboratories. Copyright © 2014 John Wiley & Sons, Ltd.