Development of a chromatography free method based on DART-Triple Quadrupole mass spectrometry for targeting safflower and turmeric as adulterants in saffron

Direct analysis in real time-mass spectrometry (DART-MS) is a rapid and accurate analytical technique that does not require extensive sample preparation and has been exploited in food analysis for the detection of contaminants including pesticides, mycotoxins and in forensics1,2. Saffron is a valuable spice derived from Crocus sativus stigmas and due to the high costs has been the main target of many fraudulent actions. For saffron quality assessment the ISO 3632-1:2011 is applied, which relies on spectrophotometric and chromatographic analysis. Despite the traditional methods requiring complex and long protocols, new robust and fast methods are urgently demanded in order to detect any possible adulterant in saffron at a concentration lower than 20% this last representing the lowest level that can be detected by conventional methodologies3. In this note we describe the development of a fast, robust, and high throughput screening method for safflower and turmeric detection as adulterants in safflower. The study explores the potential of DART-MS combined with targeted Multiple Reaction Monitoring (MRM) on a DART-EVOQ triple quadrupole mass spectrometer for the detection and quantification of safflower and turmeric in saffron at the lowest level of 5%. Safflower and turmeric powders (n=2 each) and saffron pure or adulterated with safflower (5-10-20%, n=2 each) and turmeric (5-10-20%, n=2 each) were briefly extracted with a mixture of water/solvent and analyzed by DART-MS without further preparation. Calibration curves for each adulterant were created by mixing saffron and adulterants extracts at varying inclusion levels (covering the range 10-70%). By running full scan and Product Ion Scan experiments some potential markers were identified and after selection of the best transitions for each marker upon optimization of the collision energy, MRM experiments were carried out tailored to perform quantitative analysis. Specific markers along with their main fragments for safflower 116.2>70.1; 446.2>116.2 m/z and for turmeric 368.9>116.2; 339>116.2 m/z were confirmed as suitable markers for detecting adulteration. Calibration curves showed a strong correlation, further improved with the introduction of an internal standard, confirming the successful development of a rapid, high-throughput method for detection of traces of safflower and turmeric in saffron ad. Summarizing a quick DART – MS/MS target method was developed on the new EVOQ triple Quadrupole mass spectrometer capable of detecting the addition of tiny amounts of safflower and turmeric adulterating saffron at the lowest level of 5% through the detection of two markers and relative transitions