Thin-layer Chromatography With Flame Ionization Detection Research Articles

Evaluation on the fatigue and self-healing properties of aged and rejuvenated SBS-modified asphalt

To investigate the fatigue and self-healing properties of aged and rejuvenated SBS-modified asphalt, soybean oil (SBO), epoxidized soybean oil (ESO), and commercial rejuvenators (LBS) were selected as asphalt rejuvenators. The fatigue performance of the asphalt was assessed through a time sweep procedure using a dynamic shear rheometer (DSR) instrument. Subsequently, a series of fatigue-healing-fatigue tests were conducted with varying healing times and damage degrees to analyze the self-healing characteristics of the asphalt. The rejuvenation and self-healing mechanisms were elucidated through a fluorescence microscope, Fourier transform infrared spectroscopy (FTIR), and thin-layer chromatography with flame ionization detection (TLC-FID) tests. The results revealed that the fatigue life of aged SBS asphalt deteriorated by more than 17% compared to unaged asphalt, and the self-healing properties were also weakened. However, both the fatigue life and self-healing properties could be significantly restored through the addition of rejuvenators, with SBO exhibiting the most pronounced effect in their restoration, followed by LBS and ESO. Furthermore, the self-healing capacity of the asphalt was notably affected by both the healing time and damage degree. Microstructure test results showed that in aged SBS-modified asphalt, lighter components dissipated, and the polymer deteriorated, contributing to the decline in self-healing performance. The presence of a substantial quantity of lightweight components in SBO expedited wetting and molecular diffusion at the damaged interface within the asphalt, thereby restoring the self-healing properties of the aged asphalt.

Properties and mechanism of Re-refined engine oil bottom rejuvenated aged asphalt

• 1. Re-refined engine oil bottom (REOB) is similar in composition to asphalt and contains more light components. • 2. The REOB can recover the physical and rheological properties of the aged asphalt. • 3. The REOB can restore the generic fractions and functional groups of the aged asphalt. • 4. REOB-1 has higher content of aromatics and higher permeability into aged asphalt of REOB-1 than those of REOB-2. The asphalts with different aging degrees (mildly, moderately and severely aging) were obtained by indoor aging test to estimate the rejuvenated effect of Re-refined engine oil bottom (REOB) on properties of asphalt with different aging extent. Two kinds of REOB (REOB-1 and REOB-2) with different contents were added into three aging asphalts respectively by melt blending method. The influences of different REOBs on the physical and rheological properties of asphalt with different aging degrees were studied. The thin-layer chromatography with flame ionization detection (TLC-FID), the Fourier transform infrared spectrometer (FTIR) and the permeability test were conducted to analyze the rejuvenated mechanism of REOB on properties of aged asphalt from the points of generic fractions, functional groups and diffusing ability. Results show that the REOB can partly recover the properties of aged asphalt, and the appropriate content of REOB is recommended to be around 15 wt%. Compared between the two REOBs, the REOB-1 has better rejuvenation effect on the aged asphalt than the REOB-2, which can be ascribed to higher content of aromatics and higher permeability into aged asphalt of REOB-1 than those of REOB-2.

Study on the blending behavior of asphalt binder in mixing process of hot recycling

The blending behavior of aged and virgin asphalt binder is one of the most critical problems in the mixing process of hot recycling. To accurately measure the participation degree of aged asphalt and optimize the mixing process of hot recycling, a series of laboratory tests were designed by using magnetite aggregate and thin-layer chromatography with flame ionization detection (TLC-FID) for the first time. In this study, 24 different lab-mixing conditions were deliberately adopted to investigate the impact on the DoB of aged and virgin asphalt binders, including mixing amount of RAP, mixing amount of rejuvenating agent, mixing time, mixing temperature, mixing orders and the thickness of asphalt film. The results indicated that the aged and virgin asphalt cannot be completely blended in the mixing process and DoB is only about 40–60 % in general. The DoB decreases with the increase of asphalt film thickness and it decreases by 30 % when asphalt film thickness is 9 µm. DOB increased with the content of RAP and rejuvenating agent up to 70 % which same as mixing sequence. Although the mixing time and temperature can promote DOB, the mixing time and temperature should be controlled within 240 s and 170 °C, otherwise the accuracy of DOB will be affected.

Rapid measurement of total lipids in zooplankton using the sulfo-phospho-vanillin reaction.

Zooplankton provide a vital source of nutrition to a variety of fish and marine predators. Measuring the total lipid content of zooplankton provides important information about diet quality available to predators, revealing details about trophic dynamics and ecosystem status. We analyze the performance of a microplate assay, utilizing the sulfo-phospho-vanillin (SPV) reaction, to quantify the total lipid content of various large crustacean zooplankton in a rapid and high throughput manner. Pilot experiments were performed by measuring the total lipid content of purchased freeze-dried zooplankton (Calanus finmarchicus and Euphausia superba) by both SPV and gravimetric analysis (low throughput and requires large sample size). The results of the SPV assay were not statistically different from gravimetric analysis for either species (p > 0.05). Further, an inter-laboratory comparison study was performed to measure the total lipid content (% of wet mass) of field-collected Arctic and North Pacific zooplankton (copepods (n = 19) and euphausiids (n = 29)) of various species utilizing multiple analysis methods. Results from thin layer chromatography with flame ionization detection (TLC-FID) demonstrated that lipid classes in zooplankton samples varied in composition of steryl/wax esters (3-95%), triacylglycerols (1-52%), free-fatty acids (0.4-25%), sterols (0-4%) and polar lipids (1-42%). Despite this variation in lipid class composition among samples, the results of the SPV assay agreed well with gravimetric analysis. The mean absolute and relative differences between SPV and gravimetric analysis for all zooplankton lipids in this study were 1.0% and 11.6%, respectively. The SPV assay is rapid (<2 hours), high throughput (25 samples processed in parallel), low cost (supplies <$ 0.67 per sample), precise (inter assay CV = 6.9%, intra assay CV = 6.0%), sensitive (limit of detection < 1.7 micrograms of lipid per analysis), and accurate when calibrated with appropriate standards.

Changes of components and rheological properties of bitumen under dynamic thermal aging

Bitumen material is inevitably affected by environmental factors in the process of use, which leads to bitumen aging or oxidation, thus accelerating the performance deterioration of asphalt pavement. However, the traditional aging method has carried out under a specific constant temperature, which cannot simulate the aging behavior of bitumen under dynamic thermal change. Therefore, three dynamic thermal aging processes at different temperatures were selected to simulate the aging process of bitumen under thermal dynamic change in this work. Thin-layer chromatography with flame ionization detection (TLC-FID), Dynamic shear rheometer (DSR), Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and Atomic force microscopy (AFM) were utilized to test the components, rheological properties, prominent functional groups and microstructure of bitumen under different aging conditions. The results show that with the increase of aging cycles, the content of saturates and aromatics components in bitumen decreases, and the content of asphaltenes increases obviously under the higher temperature range for aging cycles. Secondly, the aged bitumen gradually hardens and becomes brittle, especially under the dynamic thermal of the peak temperature of 200 °C, the deterioration of bitumen performance after 20 cycles exceeds the impact of TFOT for 15 h. In addition, for bitumen, dynamic thermal aging is also a thermal oxygen aging behavior, and the roughness and altitude of the bee structure decrease. Overall, this work provides some new ideas for the aging behavior of bitumen under dynamic thermal changes.

Analysis of rheological properties and aging mechanism of bitumen after short-term and long-term aging

Bitumen aging is one of the main causes of pavement performance deterioration. It is of great significance to clarify the impacts of different aging degrees on bitumen performance, molecular composition, and components for the laboratory simulation of bitumen aging and the analysis of the aging mechanism. For this purpose, in this study, two types of virgin bitumen were selected, and the rolling thin-film oven test (RTFOT) and the pressure aging vessel (PAV) methods were employed for testing according to the following designs: RTFOT (85–385 min, interval 60 min), PAV (10–30 h, interval 5 h), and RTFOT + PAV (85 min RTFOT + 10–30 h PAV, interval 5 h). Dynamic shear rheological (DSR) and bending beam rheological (BBR) tests were used to study the high- and low-temperature rheological properties of bitumen under different aging conditions. Based on Fourier-transfer infrared (FT-IR) spectroscopy, gel permeation chromatography (GPC), and rod thin-layer chromatography with flame ionization detection (TLC-FID) tests, the effects of different aging conditions on the functional groups, molecular weights, and components of bitumen were analyzed to explore the aging mechanism of bitumen. The result showed that compared with the RTFOT + PAV and RTFOT aging modes, PAV aging had a weaker influence on the bitumen rheological properties. The RTFOT aging method had a greater impact on the sulfoxide index (SI), aromatic index (AI), and long-chain index (LCI) but a lesser effect on the carbonyl index (CI); however, the PAV aging method had a significant impact on CI. The RTFOT + PAV aging method had the greatest influence on CI, SI, AI, and LCI. Moreover, for the RTFOT and PAV aging modes, after aging for a certain period, the proportions of the large-molecular-size (LMS), medium-molecular-size (MMS), and small-molecular-size (SMS) components tended to be stable. In the RTFOT + PAV aging mode, with prolonged aging time, there was no obvious stable trend in the proportion of the three components. Compared with the RTFOT and PAV aging modes, the RTFOT + PAV aging mode had a greater impact on the number of bitumen molecules. Under RTFOT and PAV, the aged bitumen exhibited a decrease in aromatics, an increase in resins and asphaltenes, and a basically unchanged proportion of saturates. Under the RTFOT + PAV aging mode, the aromatics decreased, the resins and asphaltenes increased, and the saturates decreased. For bitumen aging, when the long-term aging test conditions are limited, the RTFOT aging test can be used instead; for example, RP20 can substitute R385.

Understanding the role of waste cooking oil residue during the preparation of rubber asphalt

Bio oil was proved an effective modifier to improve the compatibility of rubber asphalt. However, the pathway in which the bio oil enhances the compatibility of rubber asphalt remains unclear. To understand the role of the bio oil in rubber asphalt during preparation process, the waste cooking oil residue (WCOR) was incorporated during the preparation of rubber asphalt in different scenarios. The compatibility of the prepared rubber asphalts was examined through the cigar tube test, the rheological characterization and the morphology observation. The compositional change of ground tire rubber (GTR) extracted from the prepared rubber asphalts was analyzed via the thermogravimetric analysis (TGA), and the chemical and fractional composition of the asphalt phase separated from the three rubber asphalts was analyzed via the Fourier transform infrared spectroscopy (FTIR) test and the thin-layer chromatography with flame ionization detection (TLC-FID) test. Results showed that the compatibility of the rubber asphalt with GTR swelled by WCOR prior to preparation was significantly improved compared with that of the rubber asphalt with untreated GTR and the rubber asphalt prepared by blending GTR and WCOR simultaneously. The results from chemical and compositional characterization suggested that the improved compatibility of the rubber asphalt incorporating GTR pre-swelled with WCOR was mainly attributed to the extended release of nature rubber (NR) and traces of synthetic rubber (SR) and inorganic filler into the asphalt phase.

Effect of Aging on Chemical Composition and Rheological Properties of Neat and Modified Bitumen.

The aim of this research was to define the effect of oxidative aging on the chemical and rheological properties of neat and styrene-butadiene-styrene (SBS) polymer-modified bitumen. The experimental research had two objectives: firstly, the short and long-term effects of aging on the properties of neat and polymer-modified bitumen were investigated. Then, the aging indexes based on chemical and rheological properties to describe the age of unknown bitumen were established. Aging characteristics such as the Gaestel index, sulfoxide and carbonyl indexes, linear viscoelastic strain range, crossover temperature, and Glover–Rowe parameter were analysed for laboratory aged and naturally aged neat and polymer-modified bitumen. The functional composition of aged bitumen was evaluated by measuring absorption with Fourier transform infrared (FT-IR) attenuated total reflection (ATR) spectrometer. The saturates, aromatics, resins, and asphaltenes (SARA) fractions were determined with thin layer chromatography with flame-ionization detection (TLC-FID) to determine the colloidal instability index (Gaestel index). Finally, the complex shear modulus was determined with dynamic shear rheometer (DSR) to evaluate the influence of aging on the bitumen mechanical performance.

Transitions of component, physical, rheological and self-healing properties of petroleum bitumen from the loose bituminous mixture after UV irradiation

In the bituminous mixture, the petroleum bituminous film wrapped in the surface of aggregate is very thin, which is obviously different from the neat bitumen. In this research, the most commonly used dense bituminous mixture (AC-13) was designated for the ultraviolet (UV) irradiation simulation test. The loose bituminous mixture was exposed under the UV irradiation for 7, 14 and 28 days respectively, and the UV irradiation intensity was 21.0 w/m2. After aging, the bitumen was recovered with the centrifuge separation method, the SARA components of the recovered bitumen (RB) was studied by the Thin-layer chromatography with flame ionization detection (TLC-FID). Meanwhile, the physical and rheological performance of the RB was investigated by the three major conventional indices and dynamic shearing parameters. In addition, the self-healing performance of bitumen was characterized by complex viscosity frequency-sweep test, capillary test and surface energy test before and after UV irradiation. The results show that with the extension of UV irradiation time, the chemical components of RB change obviously, which results in the deterioration of its colloid stability. Meanwhile, the physical and rheological performance of RB transitioned significantly (the decreases of penetration, ductility and phase angle of RB, and the increase of the softening point and complex modulus), indicates the RB becomes more embrittlement and hardening. Also, the worse flow behavior, the worse capillary fluidity and the lower surface free energy of RB result in the degradation of the self-healing performance of bituminous concrete.

Chemical characterization of natural and anthropogenic-derived oil residues on Gulf of Mexico beaches

Oil residues originating from the Deepwater Horizon (DWH) incident persist on Gulf of Mexico beaches alongside oil from offshore industrial activity, natural seepage, and asphalt from parking lots and roads. To determine the primary differences in the chemical composition of these oil residues, a variety of samples were collected from beaches from Florida to Alabama over a two-year period from 2015 to 2017. Bulk chemical characteristics of the oil residues were examined via gas chromatography with flame ionization detection (GC-FID) and mass spectrometry (GC–MS), as well as thin layer chromatography with flame ionization detection (TLC-FID), and attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR). These bulk chemical analyses revealed features unique to the different sample types, expanding our understanding of the chemical composition and variability of persistent oil residues, and providing a means to detect and monitor their long-term fate in the coastal environment.

Influence of Water Solute Exposure on the Chemical Evolution and Rheological Properties of Asphalt.

The properties of asphalt pavement are damaged under the effects of moisture. The pH value and salt concentration of water are the key factors that affect the chemical and rheological properties of asphalt during moisture damage. Four kinds of water solutions, including distilled water, an acidic solution, alkaline solution and saline solution were used to investigate the effects of aqueous solute compositions on the chemical and rheological properties of asphalt. Thin-layer chromatography with flame ionization detection (TLC-FID), Fourier transform infrared (FTIR) spectroscopy and dynamic shear rheometer (DSR) were applied to investigate the components, chemistry and rheology characteristics of asphalt specimens before and after water solute exposure. The experimental results show that moisture damage of asphalt is not only associated with an oxidation process between asphalt with oxygen, but it is also highly dependent on some compounds of asphalt dissolving and being removed in the water solutions. In detail, after immersion in water solute, the fraction of saturates, aromatics and resins in asphalt binders decreased, while asphaltenes increased; an increase in the carbonyl and sulphoxide indices, and a decrease in the butadiene index were also found from the FTIR analyzer test. The rheological properties of asphalt are sensitive to water solute immersing. The addition of aqueous solutes causes more serious moisture damage on asphalt binders, with the pH11 solution presenting as the most destructive during water solute exposure.

Optimal hydrated lime concentration in asphalt binder to improve photo degradation resistance

Abstract The effect of short-term oxidation, evaluated by using a Rolling Thin Film Oven Test, and the effect of weathering aging on the oxidation process of hydrated lime modified asphalts were studied. Hydrated lime (HL) has been known as an additive for asphalt mixtures and is now considered as a binder additive that increases asphalt mixture durability. HL was added to the binder in contents of 5, 10, 20, and 30 wt.%. The HL modified binders were aged by using the Rolling Thin Film Oven Test and weathering tests with xenon radiation. A storage stability test by measuring the softening points of HL modified binders was performed. The Thin Layer Chromatography with Flame Ionization Detection (TLC-FID) analysis was used to determine the fractions of resins, aromatics, asphaltenes and saturates of the binders. The aging of HL modified binders was evaluated by using Fourier transform infrared spectroscopy. According to the stability test, a hydrated lime concentration value close to 20 wt.% is the critical point at which there is a risk of segregation of the asphalt binder and hydrated lime during transportation and storage. For the sample weathering aged for 250 hours, a decrease of saturated and aromatic fractions, furthermore an increase in asphaltenes were observed for all samples. Results have shown that additions of 10 wt.% of hydrated lime in asphalt binders resulted in a higher photodegradation resistance among the other asphalt mixtures considering the carbonyl index, stability test and colloidal instability test results.

Investigation on Thermo-Oxidative Aging Properties of Asphalt Binder with Hindered Phenolic Antioxidant

Abstract The modified asphalt binders with hindered phenolic antioxidant (Irganox 1010) were prepared by melt blending, and the effects of Irganox 1010 on physical and rheological properties of base asphalt were investigated by means of conventional physical properties tests and dynamic shear rheometer (DSR) tests. The short-term and long-term thermo-oxidative aging properties of asphalts with Irganox 1010 were studied by thin-film oven test (TFOT) and pressure aging vessel (PAV) test. The influence of Irganox 1010 on the chemical structure and compositions of asphalt before and after the aging test were evaluated using Fourier transform infrared spectroscopy (FTIR) analysis and thin-layer chromatography with flame ionization detection (TLC-FID) analysis, respectively. The results show that the penetration and ductility are increased, whereas the viscosity and softening point are decreased, with the addition of Irganox 1010, and Irganox 1010 also decreases the complex modulus and increases the phase angle of asphalt binder. The antioxidant-treated binders exhibit excellent resistance to thermo-oxidative aging. Furthermore, Irganox 1010 inhibits the carbonyl (at 1,700 cm−1) index and sulfoxide (at 1,035 cm−1) index increment by oxidation of phenolic hydroxyl and degradation of ester group, and changes of chemical compositions of asphalt show that Irganox 1010 peptizes the asphaltenes and exhibits effective inhibition of gelatinization of asphalt binder during the process of thermal oxidation aging.

Laboratory Methods for Identification of Geologic Origins of Natural Asphalts with Special Emphasis on their Potential Uses: The Case of Trinidad Pitch and Utah Bitumen

It is widely acknowledged that the physicochemical properties of asphalt binders primarily dictate their performance and their end-use applications. However, limited data on the subject exists. This research investigates the physicochemical characterization of two natural bitumens: Trinidad pitch (TP) and Utah foam bitumen (UFB), using elemental analysis, Fourier transform-infrared spectroscopy (FT-IR), thin-layer chromatography with flame ionization detection (TLC-FID), proton-nuclear magnetic resonance spectroscopy (1H-NMR), and penetration, softening point, and viscosity tests. The results showed that TP differed significantly from UFB, mainly in the hydrocarbon, heteroatomic, vanadium, and clay-mineral contents. In terms of the SARA (i.e., saturates, aromatics, resins, and asphaltenes) fractions, the most striking compositional difference was that UFB contained more saturates than TP. Physical tests demonstrated that TP was characterized by lower penetration and higher softening points than UFB. These findings suggest that UFB is a potential candidate for the production of petroleum, and TP is a suitable construction material for road pavement.

An In-Depth Investigation into the Physicochemical, Thermal, Microstructural, and Rheological Properties of Petroleum and Natural Asphalts.

Over the last decade, unexpected and sudden pavement failures have occurred in several provinces in South Korea. Some of these failures remain unexplained, further illustrating the gaps in our knowledge about binder chemistry. To prevent premature pavement distress and enhance road performance, it is imperative to provide an adequate characterization of asphalt. For this purpose, the current research aims at inspecting the chemistry, microstructure, thermal, and physico-rheological properties of two types of asphalt, namely petroleum asphalt (PA) and natural asphalt (NA). The binders were extensively investigated by using elemental analysis, thin-layer chromatography with flame ionization detection (TLC-FID), matrix-assisted laser desorption ionization time-of-fight mass spectroscopy (MALDI-TOF-MS), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (RS), Nuclear magnetic resonance spectroscopy (1H-NMR), ultraviolet and visible spectroscopy (UV-VIS), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), penetration, softening point, ductility, and viscosity tests. The findings of this research have revealed the distinct variations between the chemical compositions, microstructures, and thermo-rheological properties of the two asphalts and provided valuable knowledge into the characteristics of the binders. Such insight has been effective in predicting the performance or distress of road pavement. This paper will, therefore, be of immediate interest to materials engineers in state highway agencies and asphalt industries.

Long-term weathering and continued oxidation of oil residues from the Deepwater Horizon spill

To investigate the long-term weathering of oil from the Deepwater Horizon (DWH) incident, oil-soaked sand patties were collected from Gulf of Mexico beaches from Florida to Alabama over a three-year period from 2012 to 2014. Analysis of oil residues by gas chromatography with flame ionization detection (GC-FID), thin-layer chromatography with flame ionization detection (TLC-FID), and Fourier transform infrared spectroscopy (FT-IR) indicated uniformity in their chemical composition. Some variability within and between samples was observed, arising from differences in exposure to light and water, which increase the amount of weathering. Oxygenated hydrocarbons (OxHC) produced by weathering processes dominate the majority of oil residues. These OxHC have continued recalcitrance in the environment, and increase in relative abundance over time. Analyses of the bulk characteristics of oil residues via TLC-FID and FT-IR should be continued as these techniques provide important insight into the weathering state of oil residues.

Effect of Ultraviolet Aging on Rheology and Chemistry of LDH-Modified Bitumen.

Layered double hydroxides (LDHs) are an ultravioletlight (UV)-resistant material. In this study, two types of LDHs (Mg-Al-LDHs and Zn-Al-LDHs) were applied to modify bitumen by melt-blending. The effect of ultraviolet aging on the rheology and chemistry of LDH-modified bitumen was studied by means of dynamic shear rheometer (DSR), thin-layer chromatography with flame ionization detection (TLC-FID), Fourier transform infrared spectroscopy (FTIR), and Ultraviolet-Visible (UV-Vis) spectrophotometry to reveal the mechanisms of action for LDHs and bitumen. The results showed that within the UV spectra (220–400 nm), the reflectance of Zn-Al-LDHs was larger than that of Mg-Al-LDHs. These two LDHs have different influences on the performance of bitumen. Mg-Al-LDHs had a more obvious influence on the physical and dynamic rheological properties of bitumen than Zn-Al-LDHs. Zn-Al-LDHs improved the UV-aging resistance of bitumen more. The reason can be that the reflectance of the Zn-Al-LDHs to the UV light is larger than that of the Mg-Al-LDHs. The Zn-Al-LDH-modified bitumen had more potential to improve the UV-aging resistance during the service life of asphalt pavement.

Determination of the four generic fractions of aged bitumen by thin-layer chromatography with flame ionization detection

The aging process of bitumen has been paid more and more attention by the researchers. The four generic fractions (saturates, aromatics, resins and asphaltenes) of bitumen change significantly during the aging process. The analysis of the changes of the four generic fractions of bitumen is very helpful to reveal the bitumen aging mechanisms and guide its engineering applications. In this study, the bitumen was aged by thin film oven test (TFOT) , pressurized aging vessel (PAV) test and ultraviolet (UV) aging test, respectively. Then the four generic fractions of bitumen before and after aging were analyzed by thin-layer chromatography with flame ionization detection (TLC-FID) , which was further compared with the solubility procedures and chromatographic technique ( named as Corbett method). The compositions of the expanded solvents were also investigated. Finally, the correlation between the TLC-FID and Corbett method was further studied, which revealed a proper TLC-FID meth- od for detection of aged bitumen. The bitumen solution dissolved by dichloromethane was successively expanded by n-heptane, toluene/n-heptane (80 :20, v/v) and toluene/ethanol (55: 45, v/v) , followed by TLC-FID. This method is of great significance for the analysis of the four generic fractions of bitumen and for the exploration of bitumen aging mechanisms.

Metabolism of nC11 fatty acid fed to Trichoderma koningii and Penicillium janthinellum II: Production of intracellular and extracellular lipids

Little is known about the fungal metabolism of nC10 and nC11 fatty acids and their conversion into lipids. A mixed batch culture of soil fungi, T. koningii and P. janthinellum, was grown on undecanoic acid (UDA), a mixture of UDA and potato dextrose broth (UDA+PDB), and PDB alone to examine their metabolic conversion during growth. We quantified seven intracellular and extracellular lipid classes using Iatroscan thin-layer chromatography with flame ionization detection (TLC-FID). Gas chromatography with flame ionization detection (GC-FID) was used to quantify 42 individual fatty acids. Per 150 mL culture, the mixed fungal culture grown on UDA+PDB produced the highest amount of intracellular (531 mg) and extracellular (14.7 mg) lipids during the exponential phase. The content of total intracellular lipids represented 25% of the total biomass-carbon, or 10% of the total biomass dry weight produced. Fatty acids made up the largest class of intracellular lipids (457 mg/150 mL culture) and they were synthesized at a rate of 2.4 mg/h during the exponential phase, and decomposed at a rate of 1.8 mg/h during the stationary phase, when UDA+PDB was the carbon source. Palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2) and vaccenic acid (C18:1) accounted for >80% of the total intracellular fatty acids. During exponential growth on UDA+PDB, hydrocarbons were the largest pool of all extracellular lipids (6.5 mg), and intracellularly they were synthesized at a rate of 64 μg/h. The mixed fungal species culture of T. koningii and P. janthinellum produced many lipids for potential use as industrial feedstocks or bioproducts in biorefineries.

Applications of Hydrocarbon Group-Type and Class-Type Analysis via Simulated Distillation-Mass Spectrometry for Process Upgrading Monitoring

Characterization of petroleum samples in terms of boiling point distributions is at the core of the oil business. In addition, knowledge of chemical properties like molecular weight (MW) and hydrocarbon group-type as well as class-type distributions are also important parameters for monitoring upgrading processes. This work studied the feasibility of using gas chromatography coupled to flame ionization and mass spectrometry detection (GC-FID-MS) for providing all the former mentioned parameters in a fast and simple simultaneous approach that requires less than 1 h for completion. Comparison with routine thin layer chromatography with flame ionization detection (TLC-FID) and standardized supercritical fluid chromatography (SFC) for hydrocarbon group and class-type analyses validated the approach and, furthermore, allowed one to highlight advantages or disadvantages for the compared techniques. Upgrading processes carried out with atmospheric and vacuum distillate feedstocks were monitored with the mentione...