Influence of sample extraction solutions on the detection of wheat proteins by mass spectrometry.

Routinely used methods for the detection of gluten mostly use denaturing agents and high salt concentrations to increase the extractability of the gluten fraction. These work well in combination with ELISA methods, but may have a negative effect on MS methods due to their influence on the ionization of the analyte leading to a significant reduction of signal intensities. A newly developed HPLC/MS/MS method was used to assess this influence. Four different extraction buffers were compared: 70% ethanol, TRIS-HCl, TRIS-HCl with dithiothreitol, and a commercially available cocktail solution. Unprocessed and processed wheat samples were analyzed. When analyzing unprocessed samples, a negative effect on ionization could be observed. Considering extraction capabilities and signal intensities, TRIS-HCl seemed to be the most suitable buffer in combination with the MS method. To assess whether the method was capable of detecting hidden wheat protein in different kinds of food, different food samples containing 0 to 34000 microg/g gluten were analyzed using the TRIS-HCI extraction buffer.

Application of a liquid chromatography tandem mass spectrometry method for the simultaneous detection of seven allergenic foods in flour and bread and comparison of the method with commercially available ELISA test kits.

To protect the allergic consumer, analytical methods need to be capable of detecting allergens in finished products that typically contain multiple allergens. An LC/MS/MS method for simultaneous detection of seven allergens was developed and compared with commercially available ELISA kits. The detection capabilities of this novel method were demonstrated by analyzing incurred material containing milk, egg, soy, peanut, hazelnut, walnut, and almond. Bread was chosen as a model matrix. To assess the influence of baking on the method's performance, analysis was done before and after baking. The same samples were analyzed with ELISA test kits from ELISA Systems, Morinaga, Neogen, and r-Biopharm. Peanut, hazelnut, walnut, and almond could be detected with both ELISA and LC/MS/MS regardless of whether the product was baked or not. LC/MS/MS clearly showed superior detection of milk in processed matrixes compared to ELISA, which exhibited significantly lower sensitivities when analyzing the baked products. Similar results were obtained when analyzing egg; however, one kit was capable of detecting egg in the processed samples as well.

Current perspectives and recommendations for the development of mass spectrometry methods for the determination of allergens in foods.

Allergen detection and quantification is an essential part of allergen management as practiced by food manufacturers. Recently, protein MS methods (in particular, multiple reaction monitoring experiments) have begun to be adopted by the allergen detection community to provide an alternative technique to ELISA and PCR methods. MS analysis of proteins in foods provides additional challenges to the analyst, both in terms of experimental design and methodology: (1) choice of analyte, including multiplexing to simultaneously detect several biologically relevant molecules able to trigger allergic reactions; (2) choice of processing stable peptide markers for different target analytes that should be placed in publicly available databases; (3) markers allowing quantification (e.g., through standard addition or isotopically labeled peptide standards); (4) optimization of protease digestion protocols to ensure reproducible and robust method development; and (5) effective validation of methods and harmonization of results through the use of naturally incurred reference materials spanning several types of food matrix.