Solid-phase extraction for picrocrocin determination in the quality control of saffron spice (Crocus sativus L.)

The application of solid phase extraction (SPE) in the determination of picrocrocin by UV–vis spectrophotometry has been studied in order to develop a rapid and low cost method that can be used in the industry for routine quality control of saffron spice. Parameters influencing the SPE procedure, such as concentration of the initial extract, sample size and eluents, were studied and optimized. Twenty different saffron spice samples from Greece, Iran, Italy and Spain were used in the intra-laboratory validation of the SPE method. The results indicated the selectivity, trueness, linearity, precision (repeatability: RSD < 6%, intermediate precision: RSD < 10%), good recovery (about 90%) and sensitivity (LOD = 0.30 mg L−1; LOQ = 0.63 mg L−1). The method also proved valid for overcoming the limitations of E1cm1% 257 nm due to crocetin esters in the determination of picrocrocin.