title: Diagnostic ions for the analysis of phenylalanine adducts of acrylamide and styrene by ESI-QTOF mass spectrometry.
abstract: To facilitate the detection of acrylamide or styrene adduct of amino acids by mass spectrometry based techniques, phenylalanine was used as a representative amino acid and pyrolysis was employed in conjunction with isotope labeling technique as a microscale sample preparation tool to generate the reaction products. The residues remaining after the pyrolysis of phenylalanine/styrene, phenylalanine/acrylamide, and phenylalanine/glucose mixtures at 250 °C were analyzed by electrospray quadrupole time-of-flight (ESI-QqTOF) mass spectrometry to identify the adducts. The phenylalanine/acrylamide adduct was independently synthesized for confirmation. Characteristic product ions in the tandem mass spectra were found at m/z 191 for the acrylamide adduct and at m/z 262 and 190 for its double-addition product. On the other hand, an ion at m/z 224 was shown to be diagnostic of the styrene adduct. The ability of the m/z 224 ion to predict the presence of styrene adduct in a heated phenylalanine/glucose model system was tested and verified. Detailed isotope labeling analysis of the phenylalanine/glucose model further indicated the formation of a novel adduct that was consistent with the reaction of the Amadori product with styrene. Such diagnostic ions that are needed to develop MS/MS-based screening methodologies may accelerate in the future the detection of Michael-type adducts in food.
authors: Department of Chemistry, Université du Québec à Montréal , Montréal, Québec, Canada.
authors: Fong Lam
authors: FL
authors: Chu
authors: Lekha
authors: L
authors: Sleno
authors: Varoujan Antranik
authors: VA
authors: Yaylayan
mesh_terms: D020106:Acrylamide / Q000737:chemistry*; D005947:Glucose / Q000737:chemistry; D015394:Molecular Structure; D010649:Phenylalanine / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D020058:Styrene / Q000737:chemistry*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D020106:Acrylamide; D020058:Styrene; D010649:Phenylalanine; D005947:Glucose