Laser Ablation APCI-HRMS Method for the Analysis of Cultural Heritage Materials

Analyzing cultural heritage (CH) materials, particularly organic substances, is challenging due to their complex chemical composition. A key requirement in such analyses is the use of analytical techniques that cause minimal damage to the artifact while providing the maximum amount of chemical information about the materials. Chromatographic and mass spectrometric (MS) techniques give valuable information about components of the organic materials, but these typically require a microsample from the object, along with specific preparation and instrumental conditions. For CH artifacts, techniques that work directly on the surface, thereby causing minimal damage, are far more desirable. We have developed a 355 nm optical fiber-coupled laser ablation (LA) atmospheric pressure chemical ionization (APCI)-MS system that enables the analysis of organic material directly from the solid surface of the artifact under ambient conditions with minimal surface damage. In this study, we coupled LA with APCI-Fourier transform ion cyclotron resonance (FT-ICR)-MS. The main aim was to evaluate the effectiveness of the developed LA-APCI high-resolution (HR)MS system for the analysis of five handmade mock-up materials of different paint and varnish layers and one real-life sample. The results demonstrate the analytical potential of the LA-APCI-HRMS technique, as high-quality and identifiable mass spectra were obtained for most of the analyzed materials. In the future, the developed LA-APCI-HRMS technique could be applied not only to cultural heritage but also to other fields (e.g., forensics, material science, etc.).