Polydimethylsiloxane-based wide-range mass calibration for direct analysis in real-time mass spectrometry.
Direct analysis in real-time mass spectrometry (DART-MS) is normally applied for small-molecule analysis up to about m/z 1,000. Here, for the analysis of polydimethylsiloxanes, high-mass capabilities expanding beyond m/z 3,000 are demonstrated. In addition, polydimethylsiloxanes provide an ideal mass calibration standard for positive-ion DART-MS. A mass reference list has been compiled to cover ions from m/z 200 up to m/z 2,600. Species with more than 20 silicon atoms exhibit increasingly broader isotopic patterns with decreasing abundances of the monoisotopic ions. The use of the first isotopic peaks for analyte ions above m/z 2,000 serves as a work-around and ensures easy and reproducible recognition of the reference peaks by the instrument data system. Here, the positive-ion DART mass spectra of polydimethylsiloxanes and the corresponding experimental procedures are described, and the mass reference list is provided.
Institute of Organic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany, juergen.gross@oci.uni-heidelberg.de.
Jürgen H
JH
Gross