LAUSR

A novel method was developed for quantification of bisacuron (BC) and dehydrozingerone (DZ), the functional component of turmeric (Curcuma longa.L)-containing foods, using a relative molar sensitivity (RMS) method based on the combination of HPLC-UV and 1H-NMR. The RMSs of BC and DZ using 4-hydroxybenzoic acid ethyl ester (HBE) as the internal standard were calculated to 1.66 and 2.55, respectively. Analysis of fourteen beverage products showed the high correlations between the concentrations of BC and DZ quantified by the RMS method and those quantified by absolute calibration curve method. A collaborative study was conducted by four laboratories on one beverage and one tablet products. The repeatable relative standard deviation (RSDr) of intra-laboratories ranged from 0.7 to 1.7%, and the reproducible relative standard deviation (RSDR) of inter-laboratories ranged from 2.0 to 7.3%. The RMS method enabled the quantification of analytes for which difficultly obtain standard materials such as BC and DZ, using an internal standard for which obtain routinely readily available. This RMS method is expected to be applied to quality control for food products containing turmeric.