Session: Parallel session 9 - Complex mixtures - polymers - microplastics

Comparative analysis of open-DIP FT-ICR MS pyrolysis and bio-oils

Théo VOELLINGER¹, Sébastien SCHRAMM¹, Nathan TRAULLÉ¹, Frédéric AUBRIET¹

¹Laboratoire de Chimie et Physique approche Mutli-Echelles des Milieux Complexes (LCP-A2MC), METZ, France

Bio oils, produced by pyrolysis of lignocellulosic biomass, offer a promising alternative to petroleum for platform molecules and fuel production. Pyrolysis is a highly complex process involving numerous simultaneous and successive chemical reactions, producing a complex mixture of molecules that need high-resolution mass spectrometry analysis to be finely described. This approach can be used to study the influence of the process parameters on the chemical and physicochemical properties of the produced oils to optimize biomass conversion. However, this process optimization can be tedious and require the repeated production of different oils, which is expensive, time and energy consuming hence the need for a faster method of analysis.

The real-time analysis of pyrolysis products by high-resolution mass spectrometry was developed in our group using a direct insertion probe (DIP). DIP ensures the quick heating of solid samples with temperatures and heating rates close to what can be obtained during fast pyrolysis. The resulting gas-phase species are then ionized in an atmospheric pressure chemical ionization source (APCI). The source was modified to ensure a constant gas flow of inert gas inside the device, reducing the residence time of the species in the oven (open-DIP) to be the same as the residence time of the products in a pyrolysis unit. To better understand the processes occurring in this apparatus, cellulose, the main component of lignocellulosic biomass, was chosen as a sample.

The influence of the employed gas flow was investigated. Well-known pyrolysis markers such as levoglucosan and cellobiosan were identified. Additionally, these DIP FT-ICR MS results were compared with those of a cellulose bio-oil produced in a fluidized bed reactor under the same conditions of temperature and gas flow rate. Most attributed ions were shared between the two methods, and the differences were explained and rationalized.