A rapid MALDI MS/MS based method for assessing saffron (Crocus sativus L.) adulteration

We report on a sensitive and fast quantitative MALDI-MS/MS method used to assess saffron authenticity by direct analysis through the determination of picrocrocin as the saffron authenticity marker, and using curcumin as the non-isotopic isobaric internal standard. The internal standard curcumin yielded good linearity (R² = 0.994), and with confidence intervals at 95% for intercept. The detectable maximum adulteration percentage (99.0%) was estimated interpolating the limit of detection (LOD) for the isobaric internal standard in linear regression. The LOD was 47.63 ppm, and LOQ was 56.53 ppm. Good accuracy and precision were obtained for all concentrations. The capability of the MS approach to monitor analytes in a specific, selective fashion was used to obtain a semi-quantitative adulteration percentage and to establish the adulterant by additional experiments. The detection of gardecin and its derivatives in commercial samples indicated that Gardenia jasminoides Ellis was used as the adulterant.