Atmospheric Solid Analysis Probe–Ion Mobility Mass Spectrometry of Polypropylene

Abstract

Polyolefin, including polypropylene (PP), constitutes an important class of materials. In particular, the recent interest in recycling plastic wastes necessitates their characterization as well as their degradation mechanism being understood. PP materials characterization by mass spectrometry, including polymer and additives parts, is not direct and generally involves a pyrolysis step to produce ionizable species. In this study, we extended the use of atmospheric solid analysis probe (ASAP) in combination with traveling wave ion mobility mass spectrometry (TWIM-MS) for the characterization of PP materials, including polymer as well as additives. Different commercial PP samples, from polymer standard to plastic item, were studied. The use of ASAP allow analysis to be done without any sample preparation, while TWIM-MS permitted a clear separation of polymer ions and additive signals. Several series of polymer pyrolysis residues, similar to those produced by classic pyrolysis, were obtained. Moreover, additive characterization has been done and supported by accurate mass measurements and tandem mass spectrometry experiments. Finally, this strategy put in evidence the role of additives in polymer degradation.

Atmospheric solid analysis probe mass spectrometry vs electrospray tandem mass spectrometry of polydimethylsiloxanes in positive and negative ionization modes

“…[2] Due to pyrolysis processes in ASAP, [3] polymers undergo extensive fragmentation and the resulting fragment ions are limited to the low m/z range. [2] Single-stage ASAP-MS would thus have some analogy with tandem mass spectrometry (MS/MS) coupled to a soft ionization technique such as ESI.…”

“…[2] Due to pyrolysis processes in ASAP, [3] polymers undergo extensive fragmentation and the resulting fragment ions are limited to the low m/z range. [2] Single-stage ASAP-MS would thus have some analogy with tandem mass spectrometry (MS/MS) coupled to a soft ionization technique such as ESI. Here we report the ASAP-MS analyses of symmetric polydimethylsiloxane chains (PDMS) terminated with hydroxy and ethoxy groups (further noted (H,OH)-and (Et,OEt)-PDMS, respectively) in positive and negative ionization modes (ASAP(+/-)-MS), and the results compared with the ESI(+/-)-MS/MS spectra of ammonium adducts reported previously.…”

“…ASAP-MS data were acquired using a hybrid quadrupole/time-of-flight SYNAPT G2 HDMS mass spectrometer (Waters Corp, Manchester, UK) fitted with an ASAP source conditioned for 1 h at the working temperature and gas flow rate before analysis. [2] The ASAP capillary tube was dipped in the pure polymer before its fixation to the probe holder and introduction into the ionization source (source temperature: 140°C; nitrogen flow rate: 1200 L h -1 at 650°C; corona discharge voltage: 4 kV; sampling cone voltage: 20 V; instrument control: MassLynx 4.1). ESI-MS/MS experiments were performed using a QStar Elite hybrid quadrupole orthogonal acceleration time-of-flight mass spectrometer from Applied Biosystems/SCIEX (Concord, ON, Canada) equipped with an ESI source (capillary voltage +5,500 V/-4,500 V, cone voltage at +50 V/-20 V, methanolic solution of ammonium acetate (39 μg L -1 ) and PDMS (10 μg L -1 ) injected at a flow rate of 5 μL min -1 ; instrument control: Analyst QS 2.0).…”

Characterizing synthetic polymers and additives using new ionization methods for mass spectrometry

“…In the past two decades, developments in ionization methods have significantly increased the applicability of mass spectrometry (MS) for the analysis of synthetic polymeric materials . More recently, ambient ionization approaches have provided rapid analysis with little or no sample preparation by methods such as desorption electrospray ionization (DESI), direct analysis in real time (DART), and atmospheric solids analysis probe (ASAP) . Investigations are ongoing to elucidate the processes responsible for gas‐phase ion formation .…”

Modification of a gas chromatography/atmospheric pressure chemical ionisation time-of-flight mass spectrometer as an alternative to automated atmospheric pressure solids analysis probe

“…Ray et al described the use of ASAP for the analysis of steroids and described how it was possible to influence the mode of ionisation (charge transfer versus proton transfer) by changing the source conditions. Other investigators have used ASAP for the analysis of biological fluids, nucleosides and polymers . Recently, the analysis of lipids, peptides and proteins was described by Chakrabarty et al .…”