Optimization of homonuclear 2D NMR for fast quantitative analysis: Application to tropine–nortropine mixtures

• Published in: Journal of pharmaceutical and biomedical analysis Vol. 43; no. 4; pp. 1243 - 1248
• Main Authors: Giraudeau, Patrick, Guignard, Nadia, Hillion, Emilie, Baguet, Evelyne, Akoka, Serge
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 12-03-2007; Elsevier Science; Elsevier
• Subjects: 2D NMR; Analysis; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Complex Mixtures - analysis; Complex Mixtures - chemistry; Fundamental and applied biological sciences. Psychology; General pharmacology; Hydrogen-Ion Concentration; Magnetic Resonance Imaging - methods; Medical sciences; Molecular Structure; Nortropine; Pharmacology. Drug treatments; Quantitative analysis; Temperature; Time Factors; Tropanes - analysis; Tropanes - chemistry; Tropine; Water - chemistry; 2D NMR; Tropine; Nortropine; Quantitative analysis; NMR spectrometry; Optimization; Two dimension spectrometry
• ISSN: 0731-7085; 1873-264X
• DOI: 10.1016/j.jpba.2006.10.028

Quantitative analysis by
1H NMR is often hampered by heavily overlapping signals that may occur for complex mixtures, especially those containing similar compounds. Bidimensional homonuclear NMR spectroscopy can overcome this difficulty. A thorough review of acquisition and post-processing parameters was carried out to obtain accurate and precise, quantitative 2D
J-resolved and DQF-COSY spectra in a much reduced time, thus limiting the spectrometer instabilities in the course of time. The number of
t
1 increments was reduced as much as possible, and standard deviation was improved by optimization of spectral width, number of transients, phase cycling and apodization function. Localized polynomial baseline corrections were applied to the relevant chemical shift areas. Our method was applied to tropine–nortropine mixtures. Quantitative
J-resolved spectra were obtained in less than 3
min and quantitative DQF-COSY spectra in 12
min, with an accuracy of 3% for
J-spectroscopy and 2% for DQF-COSY, and a standard deviation smaller than 1%.