| We present a study deploying compound-specific nitrogen and carbon isotope analysis of amino acids to discriminate between organically and conventionally grown plants. We focused on grain samples of common wheat and durum wheat grown using synthetic nitrogen fertilizers, animal manures, or green manures from nitrogen-fixing legumes. The measurement of amino acid δ15N and δ13C values, after protein hydrolysis and derivatization, was carried out using gas chromatography−combustion−isotope ratio mass spectrometry (GC-C-IRMS). Our results demonstrated that δ13C of glutamic acid and glutamine in particular, but also the combination of δ15N and δ13C of 10 amino acids, can improve the discrimination between conventional and organic wheat compared to stable... |
