Contents lists available at ScienceDirect Talanta journal homepage: www.elsevier.com/locate/talanta Quantification of real thermal, catalytic, and hydrodeoxygenated bio-oils via comprehensive two-dimensional gas chromatography with mass spectrometry Raquel V.S. Silva a, ⁎ , Nathalia S. Tessarolo a , Vinícius B. Pereira a , Vitor L. Ximenes b , Fábio L. Mendes b , Marlon B.B. de Almeida b , Débora A. Azevedo a, ⁎ a Universidade Federal do Rio de Janeiro, Instituto de Química, Ilha do Fundão, Rio de Janeiro, RJ 21941-598, Brazil b Petrobras, CENPES, Conversão de Biomassa, Ilha do Fundão, Rio de Janeiro, RJ 21941-915, Brazil ARTICLE INFO Keywords: Bio-oil quantification Real bio-oil Comprehensive two-dimensional gas chromatography Mass spectrometry Catalytic pyrolysis ABSTRACT The elucidation of bio-oil composition is important to evaluate the processes of biomass conversion and its upgrading, and to suggest the proper use for each sample. Comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC-TOFMS) is a widely applied analytical approach for bio-oil investigation due to the higher separation and resolution capacity from this technique. This work addresses the issue of analytical performance to assess the comprehensive characterization of real bio-oil samples via GC×GC- TOFMS. The approach was applied to the individual quantification of compounds of real thermal (PWT), catalytic process (CPO), and hydrodeoxygenation process (HDO) bio-oils. Quantification was performed with reliability using the analytical curves of oxygenated and hydrocarbon standards as well as the deuterated internal standards. The limit of quantification was set at 1 ng μL -1 for major standards, except for hexanoic acid, which was set at 5 ng μL -1 . The GC×GC-TOFMS method provided good precision ( < 10%) and excellent accuracy (recovery range of 70–130%) for the quantification of individual hydrocarbons and oxygenated compounds in real bio-oil samples. Sugars, furans, and alcohols appear as the major constituents of the PWT, CPO, and HDO samples, respectively. In order to obtain bio-oils with better quality, the catalytic pyrolysis process may be a better option than hydrogenation due to the effective reduction of oxygenated compound concentrations and the lower cost of the process, when hydrogen is not required to promote deoxygenation in the catalytic pyrolysis process. 1. Introduction Biomass is one potential feedstock that can be used as a renewable energy source [1]. Pyrolysis is a thermal decomposition process that converts this biomass into char, gas, and liquid products [2]. The liquid product, known as bio-oil or pyrolysis oil, has the potential to be used as biofuel or as feedstock for valuable chemicals [3]. Bio-oils are a very complex mixture, which contains organic species groups, including organic acids, esters, alcohols, ketones, aldehydes, anhydrosugars, phenols, aromatic hydrocarbons, furans, and nitrogen compounds, as well as large molecular oligomers (carbohydrates and derivatives, and lignin-derived oligomers) [3–7]. Due to their rich oxygen composition, high water content, low heating value, high viscosity, thermal instability, acidity, and corro- siveness, the direct use of bio-oils as fuels is restricted [5,8–10]. Therefore, one great challenge in biomass pyrolysis is to produce bio- oils of improved quality during the pyrolysis process, or by upgrading the final product. There are several processes to remove oxygenated compounds, which can be used to improve bio-oil quality: (1) the addition of a cracking catalyst into the pyrolysis process for the conversion of oxygenated compounds into more valuable products; and (2) hydrodeoxygenation process for upgrading of the bio-oil produced by conventional biomass pyrolysis using hydrogen and a catalyst at high pressures [3–5,10–12]. In this context, the elucidation of bio-oil composition is important to give insight into the catalytic pyrolysis process and the hydrodeoxygenation process, and to assess the potential use of bio-oil as biofuel or as a source of valuable chemicals [3]. Given the complex nature of bio-oil, chemical characterization of this matrix is challenging. Comprehensive two-dimensional gas chro- matography with time-of-flight mass spectrometry (GC×GC-TOFMS) has been largely used in the analyses of bio-oils due to its higher peak http://dx.doi.org/10.1016/j.talanta.2016.11.005 Received 2 August 2016; Received in revised form 1 November 2016; Accepted 2 November 2016 ⁎ Corresponding authors. E-mail addresses: raquelvieira@iq.ufrj.br (R.V.S. Silva), debora@iq.ufrj.br (D.A. Azevedo). Talanta xx (xxxx) xxxx–xxxx 0039-9140/ © 2016 Elsevier B.V. All rights reserved. Available online xxxx Please cite this article as: Silva, R.V., Talanta (2016), http://dx.doi.org/10.1016/j.talanta.2016.11.005