Polyamine quantitation by LC-MS using isobutyl chloroformate derivatives

Polyamines are an important class of metabolites that are poorly covered in standard metabolomics workflows. Here, we describe a protocol for isobutyl-chloroformate derivatization that can be applied to metabolite extracts following other metabolomics applications. This simple procedure allows for quantitative measurement of thirteen polyamines and two internal standards in a short (15-minute) LC-MS method. We report at least two triple quadrupole mass spectrometer transitions for each compound. Among these are unique transitions for co-eluting isomers N1- and N8-acetylspermidine, enabling quantitation of each isomer individually. We further define the linear dynamic range for each compound, and present data in several biological sample types. This simple and robust method enables stand-alone and post-metabolomics polyamine analysis.