Researchers from the Heritage Science Laboratory Ljubljana and the Smithsonian Institution have developed a non-destructive method for characterising surface exudates on PVC objects using high-resolution mass spectrometry. The approach relies on simple dry swabbing, designed to be accessible to museums worldwide, with the collected swabs analysed off-site to reveal detailed chemical information about the surface deposits.

The method was deployed at the Smithsonian American Art Museum and the Cooper Hewitt, Smithsonian Design Museum where 19 PVC objects from their collections were investigated. Plasticizers, fire retardants and lubricants were found in the exudates. Analysis identified plasticizers, fire retardants, and lubricants in the exudates. Notably, older artworks were found to contain more unique organic compounds than newer pieces, suggesting that both age and handling history influence the surface chemistry of PVC.

The authors conclude that “The information obtained from these analyses is important for conservators, as it enhances their understanding of the composition of plastic objects, identifies the primary plasticizers and potential degradation products or compounds with increased health-risk.”

This research was carried out in the frame of Tjaša’s Smithsonian Institution fellowship and project PVCare.

Read the full article here: Non-destructive mass spectrometry of historical PVC object surfaces with swab analysis

Figure 1: Sampling by dry swabbing (left) and analysis by non-proximate desorption photoionization mass spectrometry (right).