Comparison of QUPPE method with flow injection - mass spectrometry method for glyohosate analysis. Method validation and application to incurred samples of high starch and/or protein content and low water and fat content

Glyphosate (CAS 1071-83-6) is one of the most widely applied herbicides sprayed against emerged annual, perennial and biennial weeds in all crops including root and tuber vegetables, pulses, oil seeds, and cereals. A new Flow Injection - Tandem Mass Spectrometry (FI-MS/MS) method for the determination of Glyphosate in different matrices was developed and validated. For FI-MS/MS analysis, milled samples were extracted with deionized water, then the extract was cleaned-up by passing it through a polymeric solid phase extraction column. The purified extract was diluted with deionized water prior to FI-MS/MS analysis. FI-MS/MS analysis was performed on a triple quadrupole detector operating in multiple reaction monitoring. Validation data for FI-MS/MS method were satisfactorily compared with acceptability criteria established by Document No. SANTE/11813/2017. To confirm the trueness of data obtained with the FI-MS/MS method, described above, incurred samples, previously characterized for glyphosate by QuPPe method, were analyzed. The applied QuPPe method, was validated according to SANTE/11813/2017 and accredited ISO 17025. Chromatographic separation was conducted by Hypercarb(TM) (100×2.1 mm; 5 ?m) column from Thermo Scientific (Waltham, MA, USA). Incurred chickpea (n=5) and wheat samples (n=6) were selected among samples from official controls of imported products performed by Istituto Zooprofilattico Sperimentale of Umbria and Marche Regions. In particular, chickpeas and wheat samples were from outside EU (Canada, Ukraine, Iran, Russian Federation, USA) and were collected in different ports in central and southern Italy. For incurred chickpea samples a Glyphosate contamination ranging from 16 to 36 mg/Kg was found with both methods, whereas for wheat samples glyphosate concentration ranged from 0.3 to 2 mg/Kg. Good agreement between results obtained by the two methods indicated the FI-MS/MS approach as a valuable alternative to QuPPe method for rapid Glyphosate detection, ensuring high quality of the generated data, and therefore appearing suitable for broad monitoring programs as well as risk assessment purposes.