Thin-layer Chromatography-flame Ionization Detection Research Articles

Analysis of Rheological Properties and Regeneration Mechanism of Recycled Styrene-Butadiene-Styrene Block Copolymer (SBS) Modified Asphalt Binder Using Different Rejuvenators.

The regeneration performance of an aged styrene-butadiene-styrene block copolymer (SBS) will be significantly influenced by different rejuvenators. The objective of this study was to comparatively investigate the regeneration effect of different SBS-modified asphalt regenerators on aged SBS-modified asphalt. Four types of different regenerant formulations were selected. The optimal rejuvenator content was determined firstly using conventional performance tests. The rheological properties of the aged SBS-modified asphalt binder were evaluated by multiple stress creep recovery (MSCR) experiments. Subsequently, the regeneration mechanism of the SBS-modified asphalt binder was investigated using thin-layer chromatography-flame ionization detection (TLC-FID) and Fourier transform infrared spectroscopy (FTIR). The results showed that the rejuvenator had a certain recovery effect on the penetration, softening point, and ductility of the SBS-modified asphalt binder after aging. The SBS-modified rejuvenating agent was the most favorable among the four types of rejuvenators, where a rejuvenator dosage of 12% showed the optimal rejuvenation effect. The addition of regenerators could appropriately improve the elastic deformation capacity of the aged asphalt binder. The epoxy soybean oil in the regenerant reacted with the aging SBS-modified asphalt binder, supplementing the lost oil in the aged SBS-modified asphalt binder, dispersing the excessive accumulation of asphaltene, and making the residual SBS swell again. The viscoelastic properties of the aging asphalt binder were improved by adjusting the content of components and functional groups to achieve the purpose of regeneration.

From crude oil to bitumen: Genetic variability in chemistry and its influence on viscoelastic of binders

The chemical composition and properties of bitumen are derived from crude oil, which directly influences its viscoelastic properties. Six different crude oil sources were examined to explore how crude oil characteristics impact bitumen. The bitumen was produced through in-house atmospheric decompression distillation, and aging tests were conducted on these samples. The chemical properties of the crude oils, virgin binders, and aged binders were analyzed using Fourier Transform Infrared Spectroscopy (FTIR). Additionally, the separation and quantitative analysis of saturates, aromatics, resins, and asphaltenes (SARA) in crude oil and bitumen binders were carried out using Thin Layer Chromatography-Flame Ionization Detector (TLC-FID). Sweep tests on binders were conducted using a Dynamic Shear Rheometer (DSR). Master curves were created based on the CAM model and the 2S2P1D model to assess the dynamic viscoelastic properties of bitumen. The grey correlation method was employed to examine how bitumen chemical composition and properties affect its viscoelasticity. Results indicated that crude oil profoundly influences bitumen's chemical composition and properties. The functional group index and component content of bitumen are inherited from crude oil and are closely linked to the corresponding indices of crude oil. The functional group index, SARA, and colloidal stability coefficients of bitumen are intimately connected to the viscoelastic parameters of bitumen. The impact of the functional group index on the viscoelastic parameters is more pronounced than that of SARA content. This insight is crucial for guiding the selection of oil sources in bitumen production processes.

From Bin to Binder: Unleashing Waste Butter’s Potential as a Pioneering Bio-Modifier for Sustainable Asphalt Engineering

Exploring the interface of environmental sustainability and civil infrastructure development, this study introduces waste butter (WB), a byproduct of animal fat processing, as a novel bio-modifier in asphalt production. This approach not only recycles animal waste but also charts a course for sustainable infrastructural development, contributing to a reduced environmental impact and promoting circular economy practices. The experiments incorporated varying WB concentrations (e.g., 3%, 6%, and 9% by weight of binder) into standard AP-5 asphalt, employing advanced analytical tools for comprehensive characterization. These included thin-layer chromatography–flame ionization detection (TLC-FID), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Differential Scanning Calorimetry (DSC). The critical properties of the asphalt blends, such as penetration, softening point, viscosity, ductility, rutting factor (Dynamic Shear Rheometer), and thermal susceptibility (Penetration Index, Penetration–Viscosity Number), were assessed. FT-IR analysis indicated negligible chemical alteration with WB addition, suggesting predominantly physical interactions. TLC-FID showed a decrease in aromatic and asphaltene components but an increase in resin content, highlighting the influence of WB’s fatty acids on the asphalt’s chemical balance. The colloidal instability index (IC) confirmed enhanced stability due to WB’s high resin concentration. Meanwhile, SEM analysis revealed microstructural improvements with WB, enhancing binder compatibility. TGA demonstrated that even a minimal 3 wt. % WB addition significantly improved thermal stability, while the DSC results pointed to improved low-temperature performance, reducing brittleness in cold conditions. Rheologically, WB incorporation resulted in increased penetration and ductility, balanced by decreased viscosity and softening point, thereby demonstrating its multi-faceted utility. Thermal susceptibility tests emphasized WB’s effectiveness in cold environments, with further evaluation needed at higher temperatures. The DSR findings necessitate careful WB calibration to meet Superpave rutting standards. In conclusion, this research positions waste butter as a superior, environmentally aligned bio-additive for asphalt blends, contributing significantly to eco-friendly civil engineering practices by repurposing animal-derived waste.

Infrastructure in the Age of Pandemics: Utilizing Polypropylene-Based Mask Waste for Durable and Sustainable Road Pavements.

When navigating the environmental exigencies precipitated by global pandemics, the escalation of mask waste presents a multifaceted dilemma. In this avant-garde research, we unveil a novel approach: harnessing the sterilized shredded mask residues (SMRs), predominantly composed of 100 wt. % polypropylene, as pioneering modifiers for asphalt. Distinct proportions of SMR (e.g., 3, 6, and 9 wt. %) were judiciously integrated with fresh-virgin base AP-5 asphalt and subjected to an extensive suite of state-of-the-art examinations, encompassing thin-layer chromatography-flame ionization detection (TLC-FID), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and specific rheological metrics. The TLC-FID diagnostic trajectories highlighted the nuanced rejuvenating influence of SMR on the binder, a facet reinforced by a pronounced elevation in the thermodynamic stability index (IC). The FT-IR spectra elucidated SMR's preeminent role as a filler, negating notions of chemical reactivity. The TGA analyses unveiled an elevated thermal onset of degradation, signposting enhanced thermal resilience, whereas the DSC readings illuminated a superior thermal comportment at lower extremities. The SEM evaluations rendered a clearer panorama: there was heightened textural perturbation at escalated SMR incorporations, yet the 3 wt. % concoction showcased an optimal, coherent microtexture symbiosis with asphalt. The rheological scrutinies revealed a systematic trajectory: a diminishing penetration and ductility countered by ascending softening points and viscosity metrics. The coup de maître stemmed from the DSR analyses, unequivocally validating SMR's unparalleled prowess in curtailing rutting distress. This seminal inquiry not only posits a blueprint for refined pavement longevity but also champions a sustainable countermeasure to pandemic-propelled waste, epitomizing the confluence of environmental prudence an d infrastructural fortitude.

From Hive to Highway: Waste Honeycombs as a Sustainable Modifier for Asphalt Binder Formulations in South Korea.

Navigating the crossroads of sustainable infrastructure and innovative waste management, this research unveils the potential of waste honeycombs (WHCs)-an overlooked byproduct of apiculture-as a potent modifier for asphalt binder formulations. This endeavor addresses the dual challenge of enhancing road pavement sustainability and mitigating environmental degradation. A meticulous methodology evaluated the impact of varying WHC concentrations (5, 10, and 15 wt.%) on the asphalt binder, examining its attributes pre- and post-aging. Employing an array of analytical tools-thin-layer chromatography-flame ionization detection (TLC-FID); Fourier transform-infrared spectroscopy (FT-IR); scanning electron microscopy (SEM); thermogravimetric analysis (TGA); and a suite of conventional tests such as penetration, softening point, viscosity, ductility, dynamic shear rheometer (DSR), and multiple stress-creep recovery (MSCR)-provided a comprehensive insight into the binder's behavior. TLC-FID analyses revealed that WHC, with its 92 wt.% resin content, altered the SARA profile across distinct aging conditions, notably reducing asphaltene content, a factor linked to binder stiffness. The colloidal instability index (IC) further attested to this, pointing to a more thermodynamically stable system with WHC's inclusion. Meanwhile, FT-IR confirmed a physical interaction between WHC and asphalt without introducing new chemical entities. SEM observations highlighted the superior miscibility of WHC with asphalt, evidenced by a unique microtexture. With marked precision, TGA assessments unveiled a bolstering of asphalt's inherent thermal resilience consequent to a minor WHC integration. From the conventional tests, shifts in penetration, softening point, and viscosity were observed, with reduced viscosity, indicating improved workability. Lastly, while rutting potential was sensitive to WHC concentrations, fatigue resistance notably heightened with minor to moderate WHC inclusions. In essence, this pioneering study advocates for WHC's integration into asphalt formulations, offering enhanced road performance coupled with sustainable waste utilization. The findings underscore the synergy between environmental stewardship and infrastructural advancement.

A novel thin layer chromatography-flame ionization detection method for saturated, asphaltenes, resins, and asphaltenes group-type composition analysis with reverse order of chromatogram development.

The methodologies of asphaltenes-containing petroleum materials: saturated, aromatics, resins, asphaltenes group-type composition analysis are performed with the use of column adsorption-desorption or thin layer chromatography (TLC)-flame ionization detection under normal phase conditions with silica gel as the adsorbent. In a three-step procedure, the TLC chromatogram is developed within a decreasing distance by the mobile phase with increasing elution strength (polarity). The n-alkane used in the first step does not dissolve asphaltenes, which leads to the occlusion effect and an underestimation of the percentage of saturated hydrocarbons. In this article, the reverse order of the subsequent elution steps was proposed: the solvent polarity is simultaneously reduced and the chromatogram development distance is increased in the order dichloromethane:methanol 95:5 v/v, 3cm; toluene, 6cm; and n-hexane, 10cm. It was also intentional to reduce the weight of the applied sample to 5μg for bitumen and 2μg for asphaltene purity testing. It should be the rule that in stepwise TLC chromatogram development, the first mobile phase is a good solvent for all testing components. The IP 469 procedure should be corrected.

Quantification of lipid droplets in hatchery reared veliger larvae of the green-lipped mussel, Perna canaliculus

Domestication efforts and selective breeding in bivalve aquaculture would greatly benefit from reliable screening biomarkers in the early life stages of development (e.g., larvae). In this study the lipids remaining at the completion of embryo development in selectively-bred/hatchery reared green-lipped mussel, Perna canaliculus, were targeted and quantified using two approaches: confocal laser scanning microscopy and image analysis (CLSM/IA) on Oil Red-O stained larva (i.e., lipid droplet number and volume distribution), and Iatroscan thin layer chromatography/flame ionization detection (TLC/FID) (i.e., energetic and structural lipid classes content). Four groups of newly formed pre-feeding veliger larvae, produced from two genetically distinct families (FA, FB) that completed embryo development at either low (L, 17 °C) or high (H, 21 °C) temperatures, were evaluated. The FB produced offspring better equipped to deal with higher temperatures during embryonic development, with greater survival, higher normal development, and larger larvae than FA when developing at 21 °C. In terms of lipids content, CLSM/IA showed that each individual larva had overall between 83 and 157 lipid droplets (ranging in volume from 2.5 to 294 μm3). The TLC/FID estimation of mean total lipid content ranged from 4.1 to 6.9 ƞg larva−1 (29–39% structural lipid and 62–69% energetic lipid). Both lipid quantification methods were successful in detecting differences among larval groups with different genetic backgrounds, as well as providing insight into the ability to cope with changes in the growing environment when relying on maternal energy sources (triacylglycerol-TAG identified as the main source of energy for early development). Stronger differences between the two families were identified using CLSM/IA than with TLC/FID (i.e., with FA having overall more and larger lipid droplets). However, TLC/FID was able to distinguish FA larvae reared at high temperatures from the other groups (due to lower levels of TAG, 46% of total lipids, versus 52–56% in the other groups), therefore being more sensitive to the pooled population response compared to the individual lipid droplet quantification in CLSM/IA. The application of these tools, when fully developed, could be extended to controlled commercial operations to diagnose and predict larval performance, enabling more directed early screening and informing production and breeding decisions.

Investigation of changing SARA and fatigue properties of asphalt bitumen under ageing and analysis of their relation based upon the BP neural network

Thermal oxidation has a significant effect on asphalt binders’ saturates, aromatics, resins, asphaltenes (SARA) fractions and fatigue properties, but its effect on the SARA of different asphalt binders and the relation between SARA and the fatigue performance is not clear. In this study, thin layer chromatography/flame ionization detection (TLC/FID) was applied to analyze the SARA of the 36 specimens of original, short-term aged, and long-term aged asphalt binders. And then the viscoelastic continuum damage (VECD) model was applied to analyze these asphalt binders’ fatigue. Finally, the relation between SARA and the binders’ fatigue was determined by back-propagation (BP) neural network. The results showed that asphalt ageing can be considered to be the conversion of the light constituents to heavy constituents but the conversion ratios differed significantly for different asphalt binders. Asphalt binders of the same grade but different origins may have completely different mechanical properties and exhibit an entirely different composition conversion during ageing. Saturates can be considered the most inert constituent in asphalt. The oil source is the critical factor that determines the SARA and its degree of change during ageing. Ageing increased all of the asphalt binders’ fatigue life under a low strain level, but decreased it under high strain. The fatigue performance of asphalt binders with the same oil origin and grade but different manufacturers, did not differ significantly, either in the original or the aged states. Further, training the BP neural network showed that asphaltenes had the most significant effect on the asphalt’s fatigue behavior, followed by the resins and saturates, while aromatics had a minimal effect. And the BP neural network can forecast asphalt binders’ fatigue performance accurately based upon the SARA.

Uncovering the Hidden Value of Waste Cow Bones Towards their Use as a Sustainable Biofiller for Hot-Mix Asphalt Paving Applications

This work is aimed at uncovering the hidden value of waste cow bones towards their use as a sustainable biofiller for hot-mix asphalt (HMA) paving applications. To do so, the effect of various contents of calcined cow bone powder (e.g., 5, 10, and 15 wt. % CBP) on the AP-5 bitumen performance was investigated. Numerous lab techniques were adopted to assess the physicochemical attributes of finished filler-asphalt mastics, namely: elemental analysis, Fourier transform-infrared spectroscopy (FT-IR), thin-layer chromatography-flame ionization detection (TLC-FID), needle penetration, ring and ball softening point, Brookfield viscometer, and ductility. Iatroscan analysis revealed that the CBP treatment did not alter the saturates but induced an increase in the fractions of aromatics/asphaltenes and a decrease in the resins. The FT-IR scan highlighted that the CBP–binder interactions were mainly governed by physical mechanisms rather than chemical ones. The empirical methods showed that the CBP incorporation enhanced the stiffness/hardness, the consistency, as well as the high-temperature performance of bituminous mixtures. Overall, the use of waste cow bones as a green biofiller is viable and profitable, and it has the potential to reduce the environmental pollution caused by the livestock industry while also improving the performance of hot-asphalt mixes and extending the pavement life at a low cost.

Upcycling Discarded Shoe Polish into High Value-Added Asphalt Fluxing Agent for Use in Hot Mix Paving Applications.

This research effort is geared towards revealing the latent potential of discarded shoe polish that might be repurposed as an asphalt fluxing agent for the construction of durable and sustainable road surfaces. To drive this creative invention, the effect of various proportions of waste shoe polish (e.g., 5, 10 and 15 wt. % WSP) on the performance of base AP-5 bitumen was inspected in great detail. A meticulous investigation of the chemical, physical, and rheological properties of the resultant combinations was carried out using a variety of state-of-the-art laboratory techniques, specifically: thin-layer chromatography-flame ionization detection (TLC-FID), Fourier transform-infrared spectroscopy (FT-IR), needle penetration, ring-and-ball softening point, Brookfield viscometer, ductility, flash/fire points, dynamic shear rheometer (DSR), multiple stress-creep recovery (MSCR), and bending beam rheometer (BBR) tests. The Iatroscan data disclosed that the continuous feeding of binder with WSP had a minor impact on SARA fractional distribution, regardless of aging. According to the FT-IR scan, the stepwise addition of WSP to the binder did not result in any significant chemical alterations in the blends. The combined outcomes of the DSR/BBR/empirical test methods forecasted that the partly bio-sourced additive would greatly improve the mixing–compaction temperatures, workability, and coating–adhesion properties of bituminous mixtures while imparting them with outstanding anti-aging/cracking attributes. In short, the utilization of waste shoe polish as a fluxing agent for hot asphalt mix production and application is not only safe, feasible, and affordable, but it has the potential to abate the pollution caused by the shoe-care market while simultaneously enhancing the overall performance of the pavement and extending its service lifespan.

Characterization and molecular mechanism of the thermal-oxidative gradient aging behavior in asphalt films

To investigate the aging differences of asphalt films in the vertical aggregate direction, a three-layers model of oxygen-asphalt-aggregate was generated to explore the molecular mechanism of gradient aging. Moreover, the asphalt-aggregate specimens aged for 10, 20, and 40 h were layered for three parts. Fourier transforms infrared spectroscopy and thin layer chromatography-flame ionization detector tests verified the simulative findings. Eventually, the moduli of the asphalt pellicles were tested using nanoindentation test. Results denote that the oxygen’s diffusion and distribution of four components are more sensitive to pressure. The aging grade and component content of the asphalt membranes at miscellaneous thicknesses have significant differences. The combined effects of component volatilization, oxidation reactions and component migration lead to mutates in the modulus gradient of the asphalt films. The carbonyl content difference between the top and bottom of the three binders are approximately 0.22, −0.13, and − 0.27, respectively. Meanwhile, the maximum difference in modulus of binders and mastics are about 2.7 and 320.2 MPa.

A multimodal analytical method to simultaneously determine monoacetyldiacylglycerols, medium and long chain triglycerides in biological samples during routine lipidomics

BackgroundMonoacetyldiglycerides (MAcDG), are acetylated triglycerides (TG) and an emerging class of bioactive or functional lipid with promising nutritional, medical, and industrial applications. A major challenge exists when analyzing MAcDG from other subclasses of TG in biological matrices, limiting knowledge on their applications and metabolism.MethodsHerein a multimodal analytical method for resolution, identification, and quantitation of MAcDG in biological samples was demonstrated based on thin layer chromatography-flame ionization detection complimentary with C30-reversed phase liquid chromatography-high resolution accurate mass tandem mass spectrometry. This method was then applied to determine the MAcDG molecular species composition and quantity in E. solidaginis larvae. The statistical method for analysis of TG subclass composition and molecular species composition of E. solidaginis larvae was one-way analysis of variance (ANOVA).ResultsThe findings suggest that the proposed analytical method could simultaneously provide a fast, accurate, sensitive, high throughput analysis of MAcDG from other TG subclasses, including the fatty acids, isomers, and molecular species composition.ConclusionThis method would allow for MAcDG to be included during routine lipidomics analysis of biological samples and will have broad interests and applications in the scientific community in areas such as nutrition, climate change, medicine and biofuel innovations.Graphical abstract

Unlocking the Hidden Potential of Cosmetics Waste for Building Sustainable Green Pavements in the Future: A Case Study of Discarded Lipsticks.

This investigation is dedicated to unlocking the hidden potential of discarded cosmetics towards building green sustainable road pavements in the future. It is particularly aiming at exploring waste lipstick (WLS) as a high-quality functional additive for advanced asphalt mix technologies. To fuel this novel innovation, the effect of various WLS doses (e.g., 5, 10, and 15 wt.%) on the performance of base AP-5 asphalt cement was studied in detail. A wide array of cutting-edge analytical lab techniques was employed to inspect in-depth the physicochemical, microstructural, thermo-morphological, and rheological properties of resultant admixtures including: elemental analysis, Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thin-layer chromatography-flame ionization detection (TLC-FID), scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), needle penetration, ring and ball softening point, Brookfield viscometer, ductility, and dynamic shear rheometer (DSR) tests. Unlike the unstable response of asphaltenes, the additive/artificial aging treatments increased the fraction of resins the most, and decreased that of aromatics; however, asphaltenes did not impair the saturates portion, according to Iatroscan research. FT-IR scan divulged that the WLS-asphalt interaction was physical rather than chemical. XRD diagnosis not only revealed an obvious correlation between the asphaltenes content and the fresh-binder crystallinity but also revealed the presence of fillers in the WLS, which may generate outstanding technical qualities to bituminous mixes. According to AFM/SEM analyses, the stepwise incorporation of WLS grew the magnitude of the “bee-shaped” microstructures and extended the roughness rate of unaged/aged binders. The prolonged consumption of the high thermal-stable additive caused a remarkable drop in the onset degradation and glass transition temperature of mixtures, thus enhancing their workability and low-temperature performance, according to TGA/DTGA/DSC data. The DSR and empirical rheological experiments demonstrated that the WLS could effectively lower the manufacturing and compaction temperatures of asphalt mixes and impart them with valuable anti-aging/fatigue-cracking assets. In a nutshell, the use of waste lipstick as an asphalt modifier is viable and cost-effective and could attenuate the pollution arisen from the beauty sector, while improving the performance of hot/warm asphalt mixes (HAM/WAM) and extending the service life of roadways.

Spent Graphite from End-of-Life Lithium-Ion Batteries (LIBs) as a Promising Nanoadditive to Boost Road Pavement Performance

To take swift action towards tackling the global pollution crisis of discarded lithium-ion batteries (LIBs) while reinforcing road structures, this investigation was undertaken. The influence of various proportions of spent graphite (e.g., 5, 10, and 15 wt.% SG), harvested from end-of-life LIBs, on the performance of base AP-5 asphalt cement was studied. Multiple laboratory techniques have been employed to characterize the internal physiochemical interaction between the additive and the binder. These techniques include: elemental analysis (EA), thin-layer chromatography-flame ionization detection (TLC-FID), Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), empirical test methods (e.g., penetration, softening point, viscosity, and ductility), dynamic shear rheometer (DSR), and multiple stress-creep recovery (MSCR). Prior to aging, SARA analysis demonstrated that the incremental SG addition into the AP-5 bitumen reduced the contents of saturates, aromatics, and resins, and increased the proportion of asphaltenes. After aging, the saturated and aromatic hydrocarbons kept decreasing; however, the resins increased and the asphaltenes declined. Accordingly, this has brought a progressive shift tendency in the stable–colloidal system for all binders from sol-state towards sol-gel-state. FT-IR scan revealed that the SG has no apparent chemical interaction with the binder, and is endowed solely with filling effects. XRD diagnosis highlighted that the steady SG incorporation into the binder amplified its crystallinity; thereby boosting the thermomechanical properties of mastics. SEM imaging unveiled that the lower-dose of SG exhibited higher compatibility within the bitumen matrix; nevertheless, the intermediate/higher-doses made the binder body relatively rougher. DSR/MSCR/conventional tests indicated that when the asphalt is blended with the graphitic powder under unaged/aged conditions, it becomes stiffer, more viscous, and less cohesive; thereby rendering it more resistant to deformation but not to cracking. In summary, it is promisingly proven that the SG could be successfully used as an asphalt additive and could be beneficial for improving paving performance and mitigating the pollution caused by dead LIBs as well.

From Street to Road: An Innovative Approach to Explore Discarded Chewing Gum as a Performance-Enhancing Modifier for Road Pavement Applications.

To uncover the potential benefits of discarded chewing gum (DCG) as a performance-enhancing modifier for road pavement applications, its influence on the asphalt binder’s attributes was profoundly examined. The base AP-5 asphalt along with its specimens dosed with various fractions of DCG (e.g., 3, 6, and 9 wt%) were analyzed by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thin-layer chromatography-flame ionization detection (TLC-FID), scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Brookfield viscometer, ring and ball softening point, needle penetration, and dynamic shear rheometer (DSR) tests were adopted to inspect the physical and rheological changes of asphalt cement after DCG incorporation. FT-IR disclosed that the asphalt-gum interaction was not chemical but physical in nature, whilst XRD demonstrated the existence of talc filler in DCG, which may confer the bituminous mixes with exceptional engineering properties. Iatroscan analysis evinced that the gum treatment particularly altered the aromatic and resin fractions; meanwhile, the content of saturates and asphaltenes remained relatively unchanged. SEM divulged that the DCG has a complete dissolution within the bitumen matrix, which becomes rougher due to higher dose administration. AFM revealed that the steady gum introduction amplified the size of bee-like structures, shrunk their peri-phase domains, and wiped out the para-phase domains entirely. TGA/DTGA/DSC data highlighted that the high-temperature-stable additive slightly affected the thermal properties of blends. DSR and empirical rheological tests showed that the waste gum made the bitumen less vulnerable to heat and tender, thereby boosting its resistance against fatigue cracking at intermediate service temperatures. On top of that, DCG widened the thermal window of bitumen performance grade (PG), and preserved its viscosity at standard temperatures, leading to maintaining an appropriate workability for asphalt mix. In brief, the use of discarded chewing gum as an asphalt modifier is feasible and could mitigate plastic pollution and provide durable roadways by delivering superior performance.

Qualitative analysis of cetomacrogol creams by thin-layer chromatography–flame ionization detection (TLC–FID)

Buffered cetomacrogol cream has been described as the cause of iatrogenic allergic contact dermatitis, while patch testing with all ingredients was, in most cases, unable to identify the sensitizing culprit. Several hypotheses had been put forward, among which the formation of a new allergen by interaction of some of the ingredients, so-called ‘compound allergy’. In order to investigate this hypothesis, a method for the qualitative analysis of cetomacrogol creams, using thin-layer chromatography with flame ionization detection (TLC–FID), is presented. All cetomacrogol cream components, i.e., a preservative and excipients were completely separated. A two-step elution system was used to separate the analytes on the Chromarods: in the first step we separated and focussed the paraffins and cetostearyl alcohol with the use of hexane-methanol–methyl tert-butyl ether (100:3:6, v/v). After drying, the same rod was then redeveloped using methanol to resolve sorbic acid from cetomacrogol 1000, whereupon detection of the cream components could be performed by direct flame ionization detection on the Chromarods. The developed method was then applied for the analysis of commercial non-buffered and buffered cetomacrogol cream samples. No newly formed allergen could be detected, thus excluding ‘compound allergy’. This method proved to be simple, cheap, and fast, enabling the separation of the auxiliary substances present in cetomacrogol cream.

Application of Thin-Layer Chromatography-Flame Ionization Detection (TLC-FID) to Total Lipid Quantitation in Mycolic-Acid Synthesizing Rhodococcus and Williamsia Species.

In addition to cell membrane phospholipids, Actinobacteria in the order Corynebacteriales possess a waxy cell envelope containing mycolic acids (MA). In optimized culture condition, some species can also accumulate high concentrations of intracellular triacylglycerols (TAG), which are a potential source of biodiesel. Bacterial lipid classes and composition alter in response to environmental stresses, including nutrient availability, thus understanding carbon flow into different lipid classes is important when optimizing TAG synthesis. Quantitative and qualitative analysis of lipid classes normally requires combinations of different extraction, derivatization, chromatographic and detection methods. In this study, a single-step thin-layer chromatography-flame ionization detection (TLC-FID) technique was applied to quantify lipid classes in six sub-Antarctic Corynebacteriales strains identified as Rhodococcus and Williamsia species. A hexane:diethyl-ether:acetic acid solvent system separated the total cellular lipids extracted from cells lysed by bead beating, which released more bound and unbound MA than sonication. Typical profiles included a major broad non-polar lipid peak, TAG and phospholipids, although trehalose dimycolates, when present, co-eluted with phospholipids. Ultra-performance liquid chromatography-tandem mass-spectrometry and nuclear magnetic resonance spectroscopy detected MA signatures in the non-polar lipid peak and indicated that these lipids were likely bound, at least in part, to sugars from cell wall arabinogalactan. Waxy esters were not detected. The single-solvent TLC-FID procedure provides a useful platform for the quantitation and preliminary screening of cellular lipid classes when testing the impacts of growth conditions on TAG synthesis.

Towards the Use of Waste Pig Fat as a Novel Potential Bio-Based Rejuvenator for Recycled Asphalt Pavement.

This article presents a novel potential bio-based rejuvenator derived from waste pig fat (WPF) for use in recycled asphalt applications. To achieve this purpose, the impact of different doses waste pig fat (e.g., 0, 3, 6, and 9 wt.% WPF) on the reclaimed asphalt pavement binder (RAP-B) performance is investigated. The unmodified and WPF-modified asphalts are characterized by means of Fourier-transform infrared spectroscopy (FT-IR), thin-layer chromatography–flame ionization detection (TLC-FID), scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Physico-rheological properties of asphalt blends are assessed through Brookfield viscometer, softening point, penetration, and dynamic shear rheometer (DSR) tests. TLC-FID data highlighted that incremental WPF addition into RAP-B restored its original balance maltenes-to-asphaltenes ratio; finding which was supported by FT-IR analysis. SEM disclosed that WPF has a great compatibility with the aged asphalt. AFM observations showed that grease treatment induced a decline in surface roughness (i.e., bee structures) and a rise in friction force (i.e., para-phase dimension) of RAP binder. TGA/DSC studies revealed that the bio-modifier not only possesses an excellent thermal stability but also can substantially enhance the binder low-temperature performance. Empirical and DSR tests demonstrated that WPF improved the low-temperature performance grade of RAP-B, reduced its mixing and compaction temperatures, and noticeably boosted its fatigue cracking resistance. The rejuvenation of aged asphalt employing WPF is feasible and can be an ideal approach to recycle both of RAP and waste pig fats.

Thin-Layer Chromatography–Flame Ionization Detection

Thin layer chromatography–flame ionization detection (TLC–FID) is a versatile analytical technique that can be used for fast analysis of organic compounds. It has been implemented in past decades for the analysis of lipids and petrochemical products, but rarely in other fields. Despite the improvement in the latest Iatroscan model and the introduction of an automatic programmable sample spotter, this system is still struggling to gain acceptance in universities and major research laboratories. The reason behind this might be a lack of awareness on the potential application of this system to other fields of analytical chemistry. This review presents TLC–FID as a mature and reliable, state of the art technique that combines the separation power of TLC with FID as a universal detector, which can be applied to the analysis of a wide variety of organic compounds. Basic operational procedures and previous literature, including its potential for ultrafast analysis of commercial samples, are discussed in order to create awareness on the potentials of this piece of equipment to other fields.

Environmental significance of lubricant oil: A systematic study of photooxidation and its consequences

Lubricant (lube) oil discharge from ships has been widely considered as normal “operational consumption”, but is now deemed to be oil pollution. Despite the chronic contamination of the marine environment by lube oil, the number of studies related to its environmental impact, characteristics, and toxicity is limited. This study is the first attempt to investigate the environmental fate of lube oil subjected to photooxidation using in situ mesocosms. A tiered approach using thin-layer chromatography–flame ionization detection (TLC–FID), Fourier-transform infrared spectroscopy (FTIR) and gas chromatography–mass spectrometry (GC–MS) demonstrated compositional changes in lube oil and the water-soluble fraction (WSF). Total polycyclic aromatic hydrocarbons (ΣPAHs) in lube oil after 96 h of photooxidation were measured at 79.8 and 41 μg/g in the control (Con) and exposure (Exp) groups, respectively. Meanwhile, the ΣPAHs concentration in WSF after 96 h was very low, at 0.25 and 0.45 μg/L in Con and Exp, respectively. FTIR and GC–MS helped identify bond changes and photoproducts in WSF. A wide range of photoproducts, including carboxylic acids, esters, anhydrides, aldehydes and ketones, were identified in WSF. Toxic effects of WSF in both the Con and Exp groups obtained after 96 h of photooxidation were evaluated on olive flounder (Paralichthys olivaceus) embryos. Morphological defects, especially tail fin fold defects, were found to be significantly elevated in both the Con and Exp groups, with marginally higher frequency in Exp. The results of this study demonstrate the need for further research on lube oil weathering, including monitoring over prolonged periods of time.