Secondary ion mass spectrometry for the identification of polymers with noncharacteristic secondary ions using multivariate statistical analysis

Eleven different, filler-free polymers were depth profiled until all secondary ion signals were stable. Discriminant function analysis and principal components analysis were performed on a dataset containing the intensities of noncharacteristic hydrocarbon secondary ions, measured in this steady state. Discriminant function analysis showed that these secondary ions were sufficient to correctly identify all polymers using leave-one-out correction. Even with principal components analysis, which uses no prior knowledge about the origin of a data point, identification was shown to be possible