Determination of deoxynivalenol and deoxynivalenol-3-glucoside in wheat and barley using liquid chromatography coupled to mass spectrometry: On-line clean-up versus conventional sample preparation techniques

In this study, we compared the performance of conventional sample preparation techniques used in mycotoxin analyses against automated on-line sample clean-up for the determination of deoxynivalenol (DON) and its conjugated derivative, deoxynivalenol-3-beta-D-glucoside (D3G), in cereal grains. Blank wheat and barley samples were spiked with DON and D3G, extracted with a mixture of acetonitrile:water (84:16, v/v) and processed by one of the following: extract and shoot, MycoSep(R) 227 clean-up columns, MycoSep 227 with an additional acetonitrile elution step and centrifugal filtration, followed by analysis with liquid chromatography tandem mass spectrometry. Based on method performance characteristics and poor recoveries (<30%) obtained for the polar D3G with some techniques, the extract and shoot approach was chosen for the inter-laboratory method comparison study. Thus, the same spiked samples were analysed in parallel by another laboratory with an in-house validated on-line sample clean-up method, utilising TurboFlow(TM) chromatography coupled to high resolution mass spectrometry. Method validation was performed by determination of specificity, linearity, recovery, intra-day precision and the limits of detection and quantification. Matrix-matched linearity (R-2 > 0.985) was established in the range of 100-1600 and 20-320 mu g/kg for DON and D3G, respectively. Average recoveries (%RSD) were acceptable with both methods for wheat and barley, ranging between 73% and 102% (3-12%) for DON and 72% and 98% (1-10%) for D3G. The benefit of using automated sample clean-up in comparison to extract and shoot is the ability to inject directly pure extracts into the mass spectrometer, offering faster analyses and improved sensitivity with minimum system maintenance. (C) 2014 Elsevier B.V. All rights reserved.