Non-destructive mass spectrometry of historical poly(vinyl chloride) object surfaces with swab analysis

A non-destructive dry swabbing sampling method was developed and validated to characterize surface exudates on heritage poly(vinyl chloride) (PVC) objects that show evidence of degradation. Coupled with non-proximate desorption photoionization high-resolution mass spectrometry (NPDPI-MS), this approach enabled direct untargeted analysis of swabs. The methodology was applied at the Smithsonian American Art Museum (Washington DC, USA) and the Cooper Hewitt, Smithsonian Design Museum (New York, USA), identifying organic compounds such as plasticizers, fire retardants, and lubricants. NPDPI-MS distinguished chemical variations within an art series and revealed differences influenced by age and handling. The efficiency of direct swab analysis was compared to direct object analysis, and the correlation between surface and bulk plasticizer content was investigated. Designed for museum accessibility, this method requires no advanced equipment for sampling while providing comprehensive chemical insights into surface exudates.