Amino Acids Determination in Meat by GC-MS

Abstract

An isotopic dilution gas chromatography - mass spectrometric (ID-GC/MS) techniques was used for amino acids determination in sausage meat. The stable isotope internal standard used was 15N-Methionine. A Trace DSQ ThermoFinnigan quadrupole mass spectrometer coupled with a Trace GC was used. Amino acids were separated on a Rtx-5MS capillary column, 30 m x 0.25 mm, 0.25µm film thickness, using a temperature program from 50oC, 1 min, 6oC/min at 100oC, 4oC/min at 200oC, 20oC/min at 300oC, (3min). The transfer line temperature was 250oC, the injector temperature 200oC and ion source temperature 250oC; splitter: 10:1. Electron energy was 70eV and emission current, 100µA. The amino acids were purified on a Dowex 50W-W8 exchange resin and were derivatized in a procedure following two steps to obtain trifluoroacetyl butyl esters. The identification of amino acids was obtained by using NIST library but also by using amino acid standards. Concentrations of amino acids was determined by using matrix calculation for methionine quantitation