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This preliminary research is focused on the task of defining an equivalent standard column set between cryogenic and flow-modulation comprehensive two-dimensional gas chromatography (GC × GC) combined with mass spectrometry (MS). Cryogenic modulation (CM) was carried out by using a loop-type device, while the flow modulator used was a seven-port wafer chip, equipped with an external accumulation loop. Initially, a common low-polarity + mid-polarity CM GC × GC column set was selected (30 m × 0.25 mm ID × 0.25 μm d f + 1.5 m × 0.25 mm ID × 0.25 μm d f), a method was developed, and a GC × GC-MS fingerprint was attained (on a sample of bio-oil derived from coconut fibers). After, a column set with the same stationary phases was selected for the flow modulation GC × GC-MS method (20 m × 0.18 mm ID × 0.18 μm d f + 5 m × 0.32 mm ID × 0.25 μm d f), with the capability to provide a-similar-as-possible separation. A side-by-side measurement of several chromatography parameters (efficiency, peak capacity, resolution, peak widths, retention factors, elution temperatures) was made. Image 1 • A standard column set for flow-modulation GC × GC has been proposed. • A standard column set for cryogenic-modulation GC × GC was also used. • A comparison was made between the flow- and cryogenic-modulation results. • An altogether very similar separation performance was attained. [ABSTRACT FROM AUTHOR]

The development of analytical techniques in the field of liquid chromatography has brought new frontiers in performance and analytical speed for the technique. The proper evaluation of the analytical boundaries achieved with those developments was not addressed in the literature, since different liquid chromatography (LC) techniques have not yet received any classification regarding their chromatographic speed. Defining chromatographic analysis speed based simply on analysis time is an outdated concept since it is sample and analyte-dependent. In this context, the application of the Average Theoretical Peak Time concept (ATPT) is proposed as a unified metric for chromatographic speed classification. This metric was evaluated using PCA analysis in a group of more than 50 publications, which generated the classification of LC methods in normal, high, hyper, and ultra-high-speed separations using ATPT. Normal speed (ATPT values greater than 18000 ms/peak) was found in HPLC, nano-LC, SFC, and CEC methods. Therefore, high-speed methods (ATPT values between 4000 and 18000 ms/peak) were found in UHPLC techniques, while LC × LC methods presented higher ATPT values between 1000 and 4000 ms/peak being classified as hyper-speed separations. ATPT can also be used as an optimization parameter, since older methods show higher ATPT values, while recent published papers show lower values of this metric. This behavior is justified due to the improvement of the LC methods over the years. This work fulfills the gap in chromatographic definitions and metrics, regarding analytical speed in one-dimensional and multidimensional liquid chromatographic techniques and shows that ATPT metrics is a robust parameter that can be used to classify the separation speed as well as a metric to evaluate the LC Method optimization. It also corrects the historical application of separation time as a metric for chromatographic speed. [Display omitted] • Chromatographic separation speed should not be defined based on separation time. • ATPT was defined using appropriate speed metric according to proprietary equations. • The qualitative parameters PCA was used to classify the LC speed based on ATPT. • ATPT metric was applied in several LC methods, including SFC, CEC, and LC × LC. • ATPT is a new method development tool for all chromatographic techniques. [ABSTRACT FROM AUTHOR]

Coffee is an important agricultural product being one of the most consumed beverages in the world. The goal of this work is to apply the pyrolysis to this residue for the production of bio-oil. The pyrolysis of the biomass (SCG) was done in a fixed bed reactor and varying the final temperature (400, 450, 500, 550 and 600 °C). The higher crude bio-oil yield was obtained at 500 °C with a flow of N 2 in 100 mL/min (mass yield = 30.51%). The bio-oil produced by pyrolysis of SCG had its chemical composition analyzed by comprehensive two-dimensional gas chromatography coupled to mass spectrometry detector (GC × GC/TOF-MS) and associated with LTPRI. This bio-oil showed potential for the production of chemical and liquid fuels, evidencing to be a good option for the destination of this waste. Its composition showed high amount of phenols, fatty acids and nitrogen compounds. The major compounds in the bio-oil sample were n-hexadecanoic acid (palmitic acid) (19%), 9-octadecenoic acid (oleic acid) (11%), octadecanoic acid (stearic acid) (10%). [ABSTRACT FROM AUTHOR]

Fourier transform infrared (FTIR) spectroscopy, combined to principal components analysis (PCA), was applied in the classification of biomasses through the composition of their bio-oil. Bio-oils were produced through pyrolysis in a bed fixed reactor, using fifteen biomass sources available in Brazil and its characterization was made using gas chromatography coupled to mass spectrometric detector (GC/qMS). Around two hundred compounds were tentatively identified in the fifteen bio-oil samples. As expected, the chemical compositions in each bio-oil were distinct. Through the chromatographic information and PCA of the FTIR spectra it was possible observed the similarity and dissimilarity of biomasses according their bio-oil compositions. PCA revealed that FTIR spectra of biomasses fell into three different groups representing distinct bio-oil chemical compositions. The biomasses that belong to group 1 showed bio-oil compositions rich in carboxylic acids, the group 2 showed bio-oil compositions consisting predominantly of phenols and group 3 showed bio-oils with a significant amount of nitrogen compounds. Such clustering information allow exploring bio-oil quality prior to pyrolysis process. [ABSTRACT FROM AUTHOR]

Mango seed waste consists of tegument and almond and represents a considerable environmental problem in Brazil, due to the large amounts produced in the industrial processing of the fruit. An interesting alternative of utilising the mango seed waste is in the production of bio-oil by pyrolysis. The aim of this study was to produce bio-oil by pyrolysis of mango seed waste and observe its detailed chemical composition. The biomass, tegument and almond, were submitted to a pyrolysis in a fixed bed reactor at different final temperatures (450 °C/550 °C and 650 °C). The higher bio-oil yield obtained for tegument was 38.8% at 650 °C and for almond 28.1% at 450 °C. The bio-oils detailed compositions were investigated using GC × GC/TOFMS allied to software tools, retention index and dispersion graphics. A total number of 108 and 120 compounds tentatively identified in tegument-bio-oil and almond-bio-oil, respectively were found. The chemical compositions in each bio-oil were different. The major classes were: phenols (32.6%) and ketones (22.9%) in tegument-bio-oil and ketones (20.6%), acids (16.8%) and hydrocarbons (7.2%) in almond bio-oil. This is the first time that bio-oil has been produced by pyrolysis of mango seed waste and these bio-oils showed potential for the production of chemical and liquid fuels, proving to be a good option for the destination of this waste. [ABSTRACT FROM AUTHOR]

Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC/TOFMS) is used to characterize complex bio-oil samples because of the high peak capacity associated with the high acquisition rate and mass spectra deconvolution capability of TOFMS. A recent application of fast GC × GC for this type of analysis improved sample throughput while achieving the same peak capacity without the use of cryogenic liquids. This work evaluates the effect of the TOFMS data acquisition rate on the quality of the analytical information obtained by GC × GC/TOFMS. In the analysis of coconut fiber bio-oil under fast GC × GC/TOFMS conditions, use of high data acquisition rates (200–300 Hz) increases the number of identifiable peaks by more than 50% compared with that achieved at the conventional rate of 100 Hz. The acquisition rate can affect the peak capacity by a factor of 3 or more. This is the first study to demonstrate the importance of optimizing the data acquisition rate, a parameter that has previously been neglected in the literature, in GC × GC/TOFMS development. Image 1 • First investigation of acquisition rates in Fast-GC × GC/TOFMS analysis. • The TOFMS data acquisition rate was optimized by monitoring the chromatographic qualitative parameters. • For performing analysis, higher acquisition rates must be used, increasing the chromatographic parameters quality. [ABSTRACT FROM AUTHOR]

Abstract Pyrolysis of rice husk (RH) is an efficient process for the transformation of biomass to bio-oil (high-added value product). Bio-oil consists of two immiscible phases (organic and aqueous) both with potential for the generation of important chemicals for the industry. The aim of this study was to produce bio-oil by pyrolysis of RH and elucidate its chemical composition. Response surface methodology (RSM) was successfully used to determine the optimal pyrolysis conditions for the RH dry bio-oil production using central composite design (CCD). Temperature and flow rate significantly affected the bio-oil production and higher dry bio-oil yield was achieved at 650 °C and N 2 flow rate of 100 mL min−1 (predicted values of 16.9%). High performance liquid chromatography with photodiode array detection (HPLC/PDA) and comprehensive two-dimensional gas chromatography with quadrupole mass spectrometry detection (GC × GC/qMS) were used to provide a comprehensive characterization (qualitative and quantitative) of both phases from RH bio-oil. Through GC × GC/qMS analysis a total number of 98 compounds were found in organic phase; from these, 62 were quantified using a developed quantitative method by relative response factors (RRFs). Phenols and ketones (cyclic ketones) were majority in the organic phase, 8.21 and 5.90 wt%, respectively, and the benzofuran (1.37 wt%) corresponds to the major identified compound. HPLC/PDA analysis evidenced a high concentration of benzenediols and furfurals in the aqueous phase. Catechol was the major compound (2063 mg L−1) followed by furfural (997 mg L−1) and hydroquinone (899 mg L−1). This is the first time that GC × GC/qMS and HPLC/PDA has been used to characterize (qualitatively and quantitatively) both phases from RH bio-oil which showed potential use as a source of high-added value chemicals. Graphical abstract Image 1 Highlights • RSM was used to optimize the rice husk bio-oil production in a bed fixed reactor. • Optimum pyrolysis conditions were obtained at 650 °C and 100 mLmin-1(N 2 flow rate). • HPLC/PDA and GC × GC/qMS was successfully used to complete bio-oil characterization. • Benzenediols and furfurals were majority in aqueous phase by HPLC/PDA analysis. • Cyclic ketones and phenols were majority in organic phase by GC × GC/qMS analysis. [ABSTRACT FROM AUTHOR]