Characterization of N-ethoxycarbonyl ethyl esters of amino acids by mass spectrometry.

Derivatization of amino acids by using ethyl chloroformate-ethanol-pyridine provides volatile products, N-ethoxycarbonyl amino acid ethyl esters (ECEEs), which are easily amenable to GC or GC-MS analysis. MS behavior of these compounds under electron-impact has been studied. The fragments observed in the spectra facilitate recognition of commonly occurring protein amino acids and characterization of unknown analogues.