New just accepted paper in a special issue about synthetic polymers of Rapid Communications in Mass Spectrometry, in collaboration with Prof. Scott M. Grayson (Tulane University, New Orleans, US).
In this work, we are investigating the suitability of Ion Mobility Spectrometry-Mass Spectrometry (IMS) for the quantification of two isomers. A cyclic poly(L-lactide) is prepared through photodimerization of its linear homologue. Since IMS can be used to differentiate cyclic-polymer ions from their linear analogues because of their more compact three-dimensional conformation, the present work envisages IMS for the quantification of residual linear polymers within the cyclic polymer sample.
By using the standard addition method to plot calibration curves, the fraction of linear contaminants in the sample is determined. Doing so, unrealistically high values of contamination were measured. These results are explained by an ionization efficiency issue. This work underlines the intrinsic limitations of IMS in the context of the quantification of isomers. Nevertheless, the linear-to-cyclic ratio can be roughly estimated by this method.