Determination of very low stable isotope enrichments of [(2)H(5)]-phenylalanine in chicken liver using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Stable isotope labeled amino acids are frequently used to examine nutritive effects on protein synthesis. This technique is characterized by tracing the incorporation of the label into newly synthesized proteins. In the present investigation, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of very low enrichment of protein-bound l-[(2)H(5)]-phenylalanine ([(2)H(5)]-phe) in chicken liver.

Effects of increasing concentrations of sodium metabisulphite (Na2S 2O 5, SBS) on deoxynivalenol (DON) concentration and microbial spoilage of triticale kernels preserved without and with propionic acid at various moisture contents.

Unground triticale kernels contaminated with 6.63 mg deoxynivalenol (DON) per kg dry matter were stored for up to 63 days at total moisture contents of 13 and 15% in order to study the time-dependent kinetics of DON concentration in dependence on graded levels of sodium metabisulfite [0, 1, 2, 3, 4 and 5 g Na2S2O5 (SBS) per kg], and in the absence and presence of 10 g propionic acid (PA) per kg. The DON concentration decreased with increasing amounts of supplemented SBS and with increasing duration of the preservation period in a bi-exponential fashion when SBS addition was ≥3 g/kg.