Characterizing synthetic polymers and additives using new ionization methods for mass spectrometry.

Abstract

New inlet and vacuum ionization methods provide advantages of specificity, simplicity and speed for the analysis of synthetic polymers and polymer additives directly from surfaces such as fibers using mass spectrometry (MS) on different commercial mass spectrometers (Waters SYNAPT G2, Thermo LTQ Velos). We compare inlet ionization methods with the recently discovered vacuum ionization method. This method, termed matrix assisted ionization vacuum (MAIV), utilizes the matrix 3-nitrobenzonitrile (3-NBN) for the analysis of synthetic polymers and additives without additional energy input by simply exposing the matrix:analyte:salt to the vacuum of the mass spectrometer. Matrix:analyte:salt samples can be introduced while dry (surfaces, e.g. glass slides, pipet tips) or slightly wet (e.g. filter paper, pipet tips). Compounds ionized by these methods can be analyzed in both positive and negative detection modes through cationization or deprotonation, respectively. The dynamic range of the experiment can be enhanced, as well as structural analysis performed, by coupling the vacuum ionization method with ion mobility spectrometry mass spectrometry (IMS-MS) and tandem mass spectrometric (MS/MS) fragmentation. The specificity of 3-NBN matrix to ionize small and large nonvolatile analyte molecules by MAIV makes this matrix a good choice for observing low-abundance additives in the presence of large amounts of synthetic polymer using MS.