Analysis of N(ε) -ethyllysine in human plasma proteins by gas chromatography-negative ion chemical ionization/mass spectrometry as a biomarker for exposure to acetaldehyde and alcohol.

Background: N(ε) -ethyllysine (NEL) is a major stable adduct formed by the reaction of acetaldehyde (AA) with lysine residues in proteins. However, its occurrence and levels in biological specimens and its relationship with AA/alcohol exposure-associated disorders have not been fully elucidated. In this study, we have developed a sensitive and specific method to quantitate NEL levels in human plasma proteins.