Rapid quantitation of curcumin in turmeric via NMR and LC–tandem mass spectrometry

A rapid, sensitive and accurate ¹H NMR method has been developed for the quantitation of curcumin isolated from Curcuma longa rhizome (turmeric) extract, the results of which were compared with a validated LC–MS/MS method. The relative standard deviations of the methods were found to be 2.49% and 3.48% for the ¹H NMR and LC–MS/MS methods, respectively. The correlation coefficients were 0.998 for ¹H NMR and 0.995 for LC–MS/MS assay in the calibration range. The recoveries at 5 mg mL⁻¹ and 50 μg mL⁻¹ concentrations averaged to 99–101% for both techniques, respectively. The uncertainty of the measurement of curcumin via ¹H NMR spectroscopy was determined to be 5.80% while in LC–ESI-MS/MS method was 7.38%.