Solid-state NMR for the study of Asger Jorn's paintings

In this work, we explore the potential of a recent NMR technology, requiring one to two orders of magnitude less sample quantity than conventional solid-state NMR, for the study of oil paintings. The aim is the detection of changes on the molecular level that may be related to the degradation of the paint. Our sample is a small paint fragment that has flaked off the canvas of Asger Jorn's work Maske from 1945, and an approximatively one-year-old zinc white reference sample. In addition to the expected signals stemming from products of the curing process, we observe chemical shifts corresponding to carboxylates indicating de-esterification and saponification. The advantage of using solid-state NMR is the possibility to study the entire sample rather than the small extractable mobile fraction. Fast spinning in conjunction with filtering techniques allows for the acquisition of 1H spectra of the mobile fraction in order to characterize it in its original environment. This could be all the more important as some hypotheses say that the loss of this mobile phase, acting as a plasticizer, is responsible for the degradation of the paint.