An ion mobility spectrometry-chemometrics combination approach for assessing adulteration in saffron (Crocus sativus L.) with synthetic colorants

The authentication of saffron is time-consuming, produces toxic waste, and needs sample manipulation. A suitable analytical technique to overcome these handicaps requires minimum preparation of sample, rapid, easy, and online analysis. Therefore, this study has proposed the application of spectral fingerprint provided by an ion mobility spectrometer (IMS) coupled with multivariate data analysis as an easy-to-use method for detecting the adulteration of saffron with other synthetic edible colorants such as Tartrazine, Sunset Yellow, Ponceau 4-R, and Erythrosine. To this end, these synthetic colorants were added to 10 saffron spice samples in varying proportions (0–30 %, w/w). Overall, 130 adulterated saffron treatments were subjected to different multivariate data analysis processing methods, and five characteristic ions were selected by the variable importance in projection (VIP > 1) as discriminative features to build the partial least squares regression (PLSR) model for the adulterated saffron spice samples. The principal component analysis (PCA) model was able to achieve 92.28 % of the explained data variance and showed reasonable discrimination between the saffron spice samples and the other four synthetic edible colorants. Furthermore, the root-mean-square error (RMSE) and the correlation of the multiple determination (R2) values for the test set mixtures of the saffron-synthetic edible colorants were between 2.39 % and 3.53 % and 0.880–0.954, respectively.