Application of hot‐stage microscopy direct analysis in real time mass spectrometry (HDM) to the analysis of polymers

Abstract

Rationale. Polymers are ubiquitous and characterisation of their chemical, thermal and mechanical properties is important in many applications. HDM is a new technique which combines optical measurements with the benefits of ambient ionisation mass spectrometry. Physical and chemical information can be obtained as a function of sample temperature, in real-time. Methods. Samples were placed on a miniaturised hot-stage between a custom-made DART source and the ion trap mass spectrometer inlet, and subjected to both linear and cycled temperature programmes. Optical images were collected using a digital microscope and mass spectra (positive and negative ion) were recorded simultaneously. Results. Mass spectra and optical images were used to monitor the thermal expansion and release of volatile oligomers from both medical and domestic grades of silicone. Series of ions separated by 74 m/z were observed, consistent with the SiOMe2 monomer; the median mass of these increased with increasing temperature up to the decomposition point (340-400 ºC). The abundance of volatile material produced decreased with repeated thermal cycling. The coefficients of thermal expansion were calculated from optical data and were in agreement with conventional measurements (2.7-3.6 x 10-4 ºC-1). Two samples of beach sand analysed for the presence of microplastics were found to contain polyethylene and polystyrene, respectively. Conclusions. Results indicate that the novel technique of HDM can be successfully applied to the characterisation of a wide range of polymers including those in complex matrices.

Differentiation of Four Polyvinylidene Fluoride Polymers Based on Their End Groups by DART-FT-ICR MS and Kendrick Plots

“…DESI demonstrated its capabilities to study polar polymers as PEG (poly ethylene glycol), PMMA (poly methyl methacrylate), or PPG (poly propylene glycol). , ASAP (atmospheric solids analysis probe) was used by Gaiffe et al for the analysis and the differentiation of PVDF based homopolymers and copolymers. To investigate a wider range of polymer compounds, DART appear to be a well-suited technique. − …”

Hot-stage microscopy - Direct Analysis in Real-time mass spectrometry (HDM) as a novel tool for monitoring thermally-driven reactions on a small scale

“…We have previously reported development of the hot-stage microscope Direct Analysis in Real-Time mass spectrometry system (HDM) and its application to the analysis of systems such as environmental microplastics and the thermal degradation of polymers [15][16]. The HDM comprises three main components as shown in Figure 1.…”