Measuring Gas-Phase Basicities of Amino Acids Using an Ion Trap Mass Spectrometer. A Physical Chemistry Laboratory Experiment

Abstract

A new experiment for the undergraduate physical chemistry laboratory has been developed that uses an ion trap mass spectrometer to measure the relative gas-phase basicities of amino acids. This experiment is based on the kinetic method, which connects kinetics measurements on two competing reaction rates to the thermodynamic properties of the reaction products. This method gives high precision (typically 2 kJ mol–1) on properties that are difficult to measure through other means. The experiment also introduces students to an active area of research in mass spectrometry and demonstrates the application of physical chemistry techniques to biochemistry.