Sub-micron proximal probe thermal desorption and laser mass spectrometry on painting cross-sections

Abstract

We demonstrate sub-micron, atomic force microscopy (AFM) proximal probe desorption of organic dyes, and subsequent detection via laser mass spectrometry. A nanothermal analysis (nano-TA) probe tip in contact with a surface is heated (1000 °C/sec) to induce thermal desorption, creating depression sizes ranging from 360-1500 nm in diameter and 20-100 nm in depth. Desorbed material is drawn through a heated capillary via vacuum, and deposits onto a graphite sample bar. Laser desorption, followed by supersonic jet-cooling and either resonant two-photon ionization (R2PI) or non-resonant ionization mass spectrometry is used to characterize the transferred 10 material. Individual, microscopic layers of organic dyes within painting cross-sections were successfully analyzed using this new approach. Separating the AFM thermal desorption step from the detection step allows for the use of analytical techniques appropriate for individual samples of material, desorbed with high spatial resolution.

Development of a Laboratory Model of a Phototroph-Heterotroph Mixed-Species Biofilm at the Stone/Air Interface

“…Although field experiments are undoubtedly instrumental in understanding the relationship between SABs and ecosystem properties, their experimental design and execution are hampered by a number of challenges. These challenges include limited and extremely small samples, complexity of sample structure, the importance of maintaining spatial integrity and inaccessibility to repeated sampling ( Owens et al, 2014 ). Furthermore, the results of many field-based studies are limited by the temporal resolution of the experiments, as many processes that might be important in structuring SAB communities and activity, such as succession, coevolution, invasion, and climate change occur over a longer time scale than those of the average research grant, limiting the understanding of the phenomena under investigation.…”

Correlated Materials Characterization via Multimodal Chemical and Functional Imaging

“…Other researchers also used similar approaches to draw material from the desorption site through a capillary into a separate collection device for the deposition onto graphite, which allowed for subsequent laser desorption and two-photon ionization. 132 Several combined AFM/MS platforms using thermal desorption have been developed. Their general applicability has been illustrated for small organic molecules including dyes, pharmaceuticals, explosives and pesticides.…”

“…This enabled the analysis of the desorbed material by gas chromatography coupled with mass spectrometry. Other researchers also used similar approaches to draw material from the desorption site through a capillary into a separate collection device for the deposition onto graphite, which allowed for subsequent laser desorption and two-photon ionization …”

Recent Progressive Use of Advanced Atomic Force Microscopy in Polymer Science: A Review

“…Although there have been some encouraging attempts to combine AFM with several optical techniques, until recently they have been limited in wavelength range or spatial resolution. The coupling of AFM with infrared and Raman spectroscopic with nanometer-scale resolution [35][36][37][38][39][40][41][42][43][44], including tip-enhanced Raman spectroscopy (TERS) [45,46] infrared scatteringtype scanning near-field optical microscopy (IR s-SNOM) [47],thermocouple (nano-TA) [48][49][50][51] atomic force microscopy-infrared spectroscopy (AFM-IR) [52][53][54][55], and photo-induced force microscopy (PiFM) [56], atomic force microscopy nuclear-magnetic resonance (AFM-NMR) [57], atomic force microscopy nuclear-rheometer (Nano-rheology) [58,59] were recently developed to overcome these drawbacks. Details about these technologies can be found in previous review articles [60][61][62][63].…”