An Optimized Two-Dimensional Quantitative Nuclear Magnetic Resonance Strategy for the Rapid Quantitation of Diester-Type C19-Diterpenoid Alkaloids from Aconitum carmichaelii

With the development of nuclear magnetic resonance (NMR)spectrometersand probes, two-dimensional quantitative nuclear magnetic resonance(2D qNMR) technology with a high signal resolution and great applicationpotential has become increasingly accessible for the quantitationof complex mixtures. However, the requirement that the relaxationrecovery time be equal to at least five times T (1) (longitudinal relaxation time) makes it difficult for 2DqNMR to simultaneously achieve high quantitative accuracy and highdata acquisition efficiency. By comprehensively using relaxation optimizationand nonuniform sampling, we successfully established an optimized2D qNMR strategy for HSQC experiments at the half-hour level and thenaccurately quantified the diester-type C-19-diterpenoidalkaloids in Aconitum carmichaelii.The optimized strategy had the advantages of high efficiency, highaccuracy, good reproducibility, and low cost and thus could serveas a reference to optimize 2D qNMR experiments for quantitative analysisof natural products, metabolites, and other complex mixtures.