Development of a supercritical fluid chromatography method with ultraviolet and mass spectrometry detection for the characterization of biomass fast pyrolysis bio oils

Abstract

The characterization of complex mixtures is a challenging issue for the development of innovative processes dedicated to biofuels and bio-products production. The huge number of compounds present in biomass fast pyrolysis oils combined with the large diversity of chemical functions represent a bottleneck as regards analytical technique development. For the extensive characterization of complex samples, supercritical fluid chromatography (SFC) can be alternative to usual separation techniques such as gas (GC) or liquid chromatography (LC). In this study, an approach is proposed to define the best conditions for the SFC separation of a fast pyrolysis bio-oil. This approach was based on SFC data obtained directly from the bio-oil itself instead of selecting model compounds as usually done. SFC conditions were optimized by using three specific, easy-to-use and quantitative criteria aiming at maximizing the separation power. Polar stationary phases (ethylpyridine bonded silica) associated to a mix of acetonitrile and water as polarity modifier provided the best results, with more than 120 peaks detected in SFC-UV.

Ultra-high performance supercritical fluid chromatography hyphenated to atmospheric pressure chemical ionization high resolution mass spectrometry for the characterization of fast pyrolysis bio-oils

“…(ii) The separation space is well occupied by the components except in the first part of the chromatogram corresponding to the isocratic step. This is not supported by UV detection which allowed to observe a large number of peaks in this first part [10] (see Fig. S1 Table 2 along with their corresponding information (mass errors, retention times of both model compounds and similar molecular formulae found in the bio-oil).…”

“…Key parameters (stationary and mobile phases, back pressure, column temperature and gradient conditions) were optimized according to a procedure developed in a previous work and based on the maximization of peak capacity [10]. The mobile phase flow-rate was 1.4 mL/min.…”

“…The make-up flow was varied from 200 to 1500 µL/min. SFC mobile phase conditions were those optimized in a previous study [10] and described in the experimental section. Two different co-solvent concentrations were considered, corresponding to initial and final gradient compositions (i.e.…”

“…In this context we guessed that SFC hyphenated to HRMS could be a more versatile analytical technique, able to provide more comprehensive information on bio-oil composition. In a previous work [10], a SFC-UV method was developed with a view to later analyzing the whole sample by SFC-HRMS. The optimization of the separation parameters was directly performed on bio-oil sample in order to take into account the complexity of such a sample at the earliest stage of method development [10].…”

“…In a previous work [10], a SFC-UV method was developed with a view to later analyzing the whole sample by SFC-HRMS. The optimization of the separation parameters was directly performed on bio-oil sample in order to take into account the complexity of such a sample at the earliest stage of method development [10]. Because of CO 2 decompression at the outlet of SFC device, only atmospheric ionization sources such as ESI or APCI can be hyphenated to SFC.…”