Crude Oil Fractions Research Articles

Predicting the toxicity of physically and chemically dispersed oil: a modelling case study with American lobster larvae (Homarus americanus).

Determining the impact of an oil spill on aquatic ecosystems is a challenge. Because of the chemical complexity of crude oil, risk assessments rely on quantitative structure associated relationships to group chemical classes of compounds based on similar modes of toxicity. Quantitative structure associated relationships like the target lipid model can be used to determine species sensitivity by determining the critical target lipid body burden (CTLBB) and can be used to calculate the toxic units (TU) of a mixture. In this study we used the CTLBB generated from single polycyclic aromatic compound toxicity data and the analytical chemistry of whole oil to predicted and validate toxicity of both water-accommodated fraction (WAF) of crude oil and chemically dispersed WAF (CEWAF) to American lobster (Homarus americanus) larvae. A two-step procedure for modelling whole oil partitioning was utilized to compute the dissolved components in each of the WAF and CEWAF dilutions. Then, a species and life stage specific CTLBB derived for lobster larvae was applied in PetroTox to compute the TUs of exposure solution. The approach used in this study was able to effectively predict the effects observed in the exposures and can be integrated into oil spill fate and effects models to improve the oil spill assessment and response.

Effect of pressure on the interaction of saturates, aromatics, and resins (S-Ar-R) during the oxidation of heavy crude oil

The oxidation characteristics of crude oil are fundamental to studying in-situ combustion and establishing the chemical reaction models. To clarify the effect of pressure on the mutual interactions among the saturate, aromatic, and resin (SAR) fractions of heavy oil, crude oil, single fractions, and binary mixtures (S/A, S/R, A/R) were investigated by using a high-pressure thermogravimetry and differential scanning calorimetry. The results indicate that the increase of pressure does not necessarily promote the heat release of saturates and aromatics during the low-temperature oxidation stage, and it does not significantly alter the reaction initial temperature and heat release of resins during the high-temperature stage. The increase in pressure accelerates the consumption of oxidants within saturates, thereby weakening their influence on other fractions. At the same time, the change in pressure can also interfere with the oxidation reactions between aromatics and resins. Overall, the increase in pressure significantly weakens the interactions among different components during co-oxidation. This conclusion is significant for simplifying the reaction model of crude oil under high pressure.

Kinetics of reduction of m‐iodonitrobenzene by aqueous ammonium sulfide under liquid–liquid phase transfer catalysis

AbstractHydrogen sulfide generated during hydrotreatment of sour crude oil fractions could be absorbed into aqueous ammonium hydroxide to produce ammonium sulfide. This ammonium sulfide can then be utilized to produce commercially valuable aromatic amino compounds by reducing the corresponding nitro compounds. In this work, the reduction of m‐iodonitrobenzene (m‐INB) to m‐iodoaniline (m‐IA) was performed by aqueous ammonium sulfide using a phase transfer catalyst, tetrabutylammonium bromide (TBAB). The study scrutinized the influences of various parameters such as concentrations of TBAB and m‐INB, as well as initial sulfide and ammonia concentrations, on the rate of reaction of m‐INB. An 11‐fold increase in reaction rate was obtained with only 0.09 kmol of catalyst TBAB per cubic meter of the organic phase. The selectivity of m‐IA was found to be100%. The reaction was found to be kinetically controlled with an activation energy of 40.0 kJ/mol. The rate of reaction of m‐INB was observed to be directly proportional to the concentrations of m‐INB, initial sulfide, and catalyst. A pseudo‐first order kinetic model was developed to correlate the conversion versus time data and an excellent agreement between observed and predicted reaction rates was obtained. The present work has very high commercial importance as it could be a viable alternative to the traditional Claus process to arrest H2S released by petroleum refineries.

Screening, Isolation and Hydrocarbon Degradation Characteristics of Yeasts from Mangrove Sediments of Kerala

The aim of the present work was to examine the hydrocarbon degradation potential of yeasts isolated from the mangrove sediments. Mangrove sediments around the world were considered to be heavily polluted with oil contaminants and the microbes dwelling in them were believed to be highly active in metabolizing and detoxifying the oil fractions. In the present study, 70 yeast isolates were screened for their lipolytic activity qualitatively and 35 of them which showed comparatively higher lipolysis were tested for their crude oil degradation ability. Screening of hydro-carbon utilizing isolates was performed on Bushnell Haas agar media overlaid with 1% crude oil and the appearance of colonies were considered a positive. Three isolates were selected based on this and were sequenced using ITS gene of the 18S region of the rDNA and identified to be Candida tropicalis. The extent of crude oil degradation was assessed by growing the isolates in basal medium supplemented with heavy crude oil as the carbon source for 21 days. The residual crude oil fractions were then analyzed using GC-MS to quantitatively measure the degradation potential of each isolate. Our results showed that the yeast strains under study could actively metabolize the crude oil including the higher chain fractions which make them efficient hydrocarbon degraders that can be used in the bioremediation processes.

Multiple-Integrated Biomarker Indexes to Assess the Responses of the Flatfish Achirus lineatus during Exposure to Light Crude Oil Water Accommodated Fraction.

In the present study, we evaluated the biological response of Achirus lineatus to water accommodated fraction (WAF) of light crude oil (American Petroleum Institute gravity 35°) during a sub-chronic bioassay (14 and 28 days) at two different concentrations: 5% v/v (1.20µg∙L- 1 expressed as total polycyclic aromatic hydrocarbons [∑25 PAH]) and 10% v/v (6.61µg∙L- 1 [∑25 PAH]). The responses were evaluated through the biomarker response index (BRI), the integrated biomarker response (IBRv2) and the bioconcentration factor (BCF). The results showed an increase in biological response in relation to WAF concentration and exposure time, which resulted in a slight and moderate disturbance in the basal condition and bioconcentration level of metals (Pb > Ni > V > Cd) in fish tissue. Results in the present study denote that flatfish such as A. lineatus may be negatively influenced by spilled light crude oil.

Bioremediation of petroleum-contaminated soil based on both toxicity risk control and hydrocarbon removal-progress and prospect.

Petroleum contamination remains a worldwide issue requiring cost-effective bioremediation techniques. However, establishing a universal bioremediation strategy for all types of oil-polluted sites is challenging. This difficulty arises from the heterogeneity of soil textures, the complexity of oil products, and the variations in local climate and environment across different oil-contaminated regions. Several factors can impede bioremediation efficacy: (i) differences in bioavailability and biodegradability between aliphatic and aromatic fractions of crude oil; (ii) inconsistencies between hydrocarbon removal efficiency and toxicity attenuation during remediation; (iii) varying adverse effect of aliphatic and aromatic fractions on soil microorganisms. This review examines the ecotoxicity risk of petroleum contamination to soil fauna and flora. It also discusses three primary bioremediation strategies: biostimulation with nutrients, bioaugmentation with petroleum degraders, and phytoremediation with plants. Based on current research and state-of-the-art challenges, we highlighted future research scopes should focus on (i) exploring the ecotoxicity differentiation of aliphatic and aromatic fractions of crude oil, (ii) establishing unified risk factors and indicators for evaluating oil pollution toxicity, (iii) determining the fate and transformation of aliphatic and aromatic fractions of crude oil using advanced analytical techniques, and (iv) developing combined bioremediation techniques that improve petroleum removal and ecotoxicity attenuation.

Interfacial tension and contact angle of asphaltenic and resinous model oil in the presence of binary salts mixtures

Using smart or low salinity waters known as green processes gained increasing attention due to their unique features and their positive impacts on the environment. In light of this fact and since there is limited knowledge about the effects of salts under engineered concentrations or binary mixtures and crude oil fractions on the interfacial tension (IFT) reduction and wettability alteration of the resinous (RSO) and asphaltenic synthetic oil (ASO), the current investigation is designed and performed for the first time. Moreover, the dynamic behavior of the IFT variation was carefully investigated and the relaxation time was obtained and modeled to see the impact of mono and divalent salts individually and in binary conditions. The relaxation times revealed that the lowest adsorption times were obtained for NaCl/CaCl2 brine regardless of the examined oil types of ASO and RSO due to the high movement affinity of the polar functional groups toward the interface consequently reducing the required time for coverage and packing of active agents at the interface. Finally, the measured contact angle values revealed a significant effect of binary salts on the wettability alteration toward strongly water-wet conditions, especially for the RSO and ASO compared with crude oil.

Acidic process fluid from hydrothermal carbonization improves dechlorination of waste PVC and produces clean solid and liquid fuels

Dechlorination of waste PVC (WPVC) by hydrothermal treatment (HTT) is a potential technology for upcycling WPVC in order to create non-toxic products. Literature suggests that acids can improve the HTT process, however, acid is expensive and also results in wastewater. Instead, the acidic process fluid (PF) of hydrothermal carbonization (HTC) of orange peel was utilized in this study to enhance the dechlorination of WPVC during HTT. Acidic HTT (AHTT) experiments were carried out utilizing a batch reactor at 300–350 °C, and 0.25–4 h. The finding demonstrated that the dechlorination efficiency (DE) is high, which indicates AHTT can considerably eliminate chlorine from WPVC and relocate to the aqueous phase. The maximum DE of 97.57 wt% was obtained at 350 °C and 1 h. The AHTT temperature had a considerable impact on the WPVC conversion since the solid yield decreases from 56.88 % at 300 °C to 49.85 % at 350 °C. Moreover, AHTT char and crude oil contain low chloride and considerably more C and H, leading to a considerably higher heating value (HHV). The HHV increased from 23.48 to 33.07 MJ/kg when the AHTT time was raised from 0.25 to 4 h at 350 °C, indicating that the AHTT time has a beneficial effect on the HHV. The majority fraction of crude oil evaporated in the boiling range of lighter fuels include gasoline, kerosene, and diesel (57.58–83.09 wt%). Furthermore, when the AHTT temperature was raised from 300 to 350 °C at 1 h, the HHV of crude oils increased from 26.11 to 33.84 MJ/kg. Crude oils derived from AHTT primarily consisted of phenolic (50.47–75.39 wt%), ketone (20.1–36.34 wt%), and hydrocarbon (1.08–7.93 wt%) constituents. In summary, the results indicated that AHTT is a method for upcycling WPVC to clean fuel.

Water-accommodated fractions of crude oil and its mixture with chemical dispersant impairs oxidase stress and energy metabolism disorders in Oryzias melastigma embryos

In this study, marine medaka (Oryzias melastigma) embryos were exposed to different concentrations of water-accommodated fractions (WAFs) and chemically enhanced water-accommodated fractions (CEWAFs) of Oman crude oil for 14 d by semi-static exposure methods. The effects on growth and development and energy metabolism process were evaluated. Results showed that embryo survival and hatchability were decreased in a dose-dependent manner with an increase in the concentration of petroleum hydrocarbon compounds, whereas the malformation exhibited a dose-dependent increase. Compared to the control, the adenosine triphosphate (ATP) content and Na+-K+–ATPase (NKA) activities of embryos exposed to both WAFs and CEWAFs were reduced, while intracellular reactive oxygen species (ROS) levels and NADH oxidase (NOX) activities were increased. Our study demonstrated that exposure to crude oil dispersed by chemical dispersant affected the growth and development of marine medaka embryos, caused oxidative stress while produced a series of malformations in the body and dysregulation in energy metabolism. In comparison, the toxic effects of chemically dispersed crude oil might be more severe than the oil itself in the equivalent diluted concentration treatment solution. These would provide more valuable and reliable reference data for the use of chemical dispersants in oil spills.

Differential biodegradation of alkanes in crude oil by three oleophilic strains

Ex situ bioremediation of crude oil in bioreactors by oleophilic bacteria permits to regulate temperature, nutrients and oxygen and the results in petroleum removal are much more effective than in situ bioremediation. This article quantify the biodegradation of alkanes which conform crude oil in bioreactors by three oleophilic strains. Samples were collected from the bioreactors and extracted in dichloromethane (10:1 aqueous/organic v/v) for amplification in GC-FID analysis of individual alkanes. 94% of crude oil (initial concentration 8.6 g l−1) is removed in 24 days by Bacillus licheniformis and in 38 days by Pseudomonas putida and Paenibacillus glucanolyticus. Higher biodegradation rates (9.0–26.5 mg l−1d−1) are reached for the lightest fraction of crude oil by Bacillus licheniformis (C10–C16), and much lower for C22–C25 alkanes (4.4–8.9 mg l−1d−1). Pseudomonas putida and Paenibacillus glucanolyticus degrade a wide range of alkanes at 1.6–9.6 mg l−1d−1, with preference over C8–C16 hydrocarbons. Heptane and octane (alkanes cited to be toxic) are difficult for biodegradation in two strains (B. licheniformis and P. putida) and a recalcitrant “window” C18–C21 is observed for the three oleophilic strains in the alkane range studied.

Research on Component Variation and Factors Affecting Minimum Miscible Pressure in Low Viscosity Oil Miscibility Process.

Miscible gas flooding is an important approach for enhancing the recovery of unconventional oil reservoirs. The injected gas and crude oil components has a significant impact on the minimum miscible pressure. In order to clarify the miscibility characteristics and factors influencing the minimum miscibility pressure, combining PVT and slim tube experiments, the minimum miscibility pressure between Tuha low viscosity oil and different injected gas was measured. Additionally, chromatography experiments were conducted to study the composition changes of produced oil. The results indicate that when the injection pressure is higher than the minimum miscible pressure, the extraction effect of injected gas on heavy fraction (C16+) in crude oil is enhanced and the extraction effect on light alkanes (C1-C6) is reduced. The increase in the content of light alkanes (C1-C6) and middle distillates (C7-C15) in crude oil reduces the minimum miscibility pressure between crude oil and injected gas. Pipeline gas can effectively extract heavy fraction from crude oil, but its breakthrough time is early. Under the same pressure, earlier breakthrough time of injected gas makes it more difficult for the crude oil and injected gas to miscible. Through the analysis of experimental results, the following main conclusions are drawn: Immiscible flooding causes heavy fraction (C16+) in crude oil to remain, which might affect the physical properties of the reservoir, increasing the difficulty of subsequent development. Gas fingering phenomenon significantly influences the miscibility of injected gas and crude oil, and the viscosity ratio of injected gas and crude oil under high-pressure conditions can be used as an important criterion for screening injected gas.

Identification of oil contamination in process water using fluorescence excitation emission matrix (FEEM) and parallel factor analysis (PARAFAC).

Fuel oil is widely used within Eskom, a power generation company in South Africa. Eskom's coal-fired power stations use up to 30,000 L of fuel oil per hour during a cold start-up, a consequence of which results in oil leaks to the dams. Oil contamination in water treatment plants causes irreversible membrane fouling, requiring costly replacement. This research work focused on the development of a rapid method for the identification of low concentrations of the water-soluble oil component fraction of crude fuel oil. For the developed method, known volumes of the water-soluble fraction of crude oil were spiked into various matrices of process water. FEEMs were collected using the patented HORIBA Aqualog spectrometer and data were modelled with PARAFAC. The results were well described with a four-component model, which included an oil component and three natural organic matter components, with a split-half validation match of 90%. The oil component was verified using linear regression of the PARAFAC component scores yielding an R2 value of 0.98. From the scores, a qualitative pass/fail test was developed such that process water can be analysed and subjected to the model to indicate the presence of oil contamination beyond a damaging threshold.

Biomarker responsiveness in Norwegian Sea mussels, Mytilus edulis, exposed at low temperatures to aqueous fractions of crude oil alone and combined with dispersant

Biological effects of aqueous fractions of a crude oil, alone or in combination with dispersant, were investigated in mussels, Mytilus edulis, exposed at three temperatures (5, 10 and 15 °C). Polycyclic aromatic hydrocarbons (PAHs) tissue concentrations were determined, together with genotoxicity, oxidative stress and general stress biomarkers and the Integrated Biological Response (IBR) index. The bioaccumulation of individual PAHs varied depending on the exposure temperature, with relevant bioaccumulation of phenantrene and fluoranthene at 5 °C and heavier (e.g. 5-rings) PAHs at 15 °C. The values and response profiles of each particular biomarker varied with exposure time, concentration of the oil aqueous fraction and dispersant addition, as well as with exposure temperature. Indeed, PAH bioaccumulation and biomarker responsiveness exhibited specific recognizable patterns in mussels exposed at low temperatures. Thus, genotoxicity was recorded early and transient at 5 °C and delayed but unremitting at 10–15 °C. Catalase activity presented a temperature-dependent response profile similar to the genotoxicity biomarker; however, glutathione-S-transferase responsiveness was more intricate. Lysosomal membrane stability in digestive cells decreased more markedly at 5 °C than at higher temperatures and the histological appearance of the digestive gland tissue was temperature-specific, which was interpreted as the combined effects of PAH toxicity and cold stress. It can be concluded that the profile and level of the biological effects are definitely different at low temperatures naturally occurring in the Arctic/Subarctic region (e.g. 5 °C) than at higher temperatures closer to the thermal optimum of this species (10–15 °C).

Embryonic exposure to water accommodated fraction of crude oil inhibits reproductive capability in adult female marine medaka (Oryzias melastigma)

The water accommodated fraction (WAF) of spilled crude oil is a severe threat to the health of marine fish. This study was conducted to investigate the effects of short-term embryonic exposure to the WAF on the ovarian development and reproductive capability of F0 adult female marine medaka (Oryzias melastigma). Following embryonic exposure to the WAF with nominal total petroleum hydrocarbon concentrations of 0.5, 5, 50, and 500 μg/L for 7 days, the number of spawned eggs and gonadosomatic indices of F0 adult females were significantly reduced at 130 days postfertilization. In these F0 adult females, the proportion of mature oocytes was significantly lower, the level of 17β-estradiol was lower, and the level of testosterone was greater than those in control group. The mRNA levels of the follicle-stimulating hormone β subunit, luteinizing hormone β subunit, cytochrome P450 aromatase 19b, estrogen receptor α and β, and androgen receptor α and β genes were upregulated, while the mRNA level of the salmon-type gonadotropin-releasing hormone was downregulated in F0 adult females exposed to the WAF during the embryonic stage. Additionally, the methylation level of vitellogenin (vtg) in F0 adult females was significantly elevated, this might have, in turn, downregulated the mRNA level of vtg. The mortality rate of the unexposed F1 embryos was significantly increased and the hatching success was significantly reduced. These results collectively indicated the necessity of incorporating and evaluating the effects of short-term early-life exposure to crude oil in the assessment of risks to the reproductive health of marine fish.

Evaluation of the Behavior of Two Tricyclic-Fused Host Systems in the Presence of Single and Mixed Isomers of the C8H10 Aromatic Crude Oil Fraction

Evaluation of the Behavior of Two Tricyclic-Fused Host Systems in the Presence of Single and Mixed Isomers of the C₈H₁₀ Aromatic Crude Oil Fraction

Kinetic modeling of dual-stage oxidative extractive denitrogenation of model fuel

The petroleum fraction of crude oil is laden with notorious nitrogen compounds, whose removal facilitates fuel oil transport and enhances the longevity of hydrodesulfurization catalysts. Petroleum refining operation thus demands the adoption of unconventional techniques, such as coupled oxidative–extractive denitrogenation. Kinetic models can provide insights into the reaction mechanism and the design and performance of reactors. In this work, nine different kinetic models were developed by applying the Langmuir–Hinshelwood and Eley–Rideal approaches to various reaction pathways. The screening of the kinetic models was done based on the values of the rate law parameters and corresponding R 2 and adjusted R 2 values calculated through a multi-parametric, non-linear regression based on the Levenberg–Marquardt algorithm. Out of all the models, the Eley–Rideal model corresponding to the rate expression rs9 was found to be the best fit, reflecting that hydrogen peroxide remained in bulk while pyridine alone was adsorbed on the catalyst. The selection of suitable extractants for the extractive removal of oxidation products was made based on their extraction efficiency and partition coefficients. The ternary liquid–liquid equilibrium (LLE) data for the (acidulated water-pyridine-isooctane) and (acidulated water-pyridine N-oxide-isooctane) systems were plotted, and Othmer–Tobias, Hand, and Bachman correlations explained the consistency of the experimental LLE data.

The changes of Trp-deficient linusorb during the oxidation and the influence of γ-tocopherol on their oxidative stability

Linusorbs (LOs), particularly the Methionine (Met)-containing yet Tryptophan (Trp)-free LO (CLB and CLP), play a significant role in shaping the quality and sensory attributes of flaxseed oil. To investigate the stability of these LOs and their oxidized forms during accelerated oxidation, the polar fractions of crude flaxseed oil were selectively removed using silica absorption and then reintroduced separately into the oil matrix along with LOs and γ-tocopherol (γ-T). Through comprehensive analysis of oxidative stability indexes, LOs content changes, oxidation kinetics, and the correlation between LOs and oxidative stability indexes, we observed that the LOs fraction alone exhibited a moderate antioxidant effect on the peroxide value (PV) but a weaker effect on the p-anisidine value (p-AV) of flaxseed oil. However, upon addition of γ-T, we observed a weak synergistic effect between γ-T and LOs in suppressing PV, while a stronger effect in suppressing p-AV. Additionally, a comparison of the oxidation kinetics of different LOs indicated that γ-T preferentially protected the oxidation of CLP over CLB. Similar protective trends of γ-T towards the methionine sulfoxide (MetO) and methionine sulfoxide (MetO2) form of LOs were also observed, albeit to a lesser extent. Correlation analysis revealed that changes in Met-containing LOs, particularly CLP, showed a high correlation with PV in the tested matrices, while MetO-containing LOs better depicted changes in p-AV. Importantly, CLP demonstrated higher susceptibility to the influence of antioxidants, making it more suitable for evaluating the peroxide value in flaxseed oil samples.

Patchouli essential oil: Unlocking antimicrobial potential for dandruff control

Abstract Dandruff causes the scalp to peel and results in itching, which is caused by one of the fungi, Malassezia globosa. Several studies have revealed that the compounds in essential oils can act as antimicrobials. To broaden insights regarding the potential compounds in essential oils, this research focuses on the potential of patchouli essential oil in inhibiting the growth of dandruff-causing microbes. One of the compounds with antimicrobial potential in patchouli oil is patchouli alcohol. The steam distillation method was used for extraction oil from dried patchouli stems and leaves to produce three different types of oil samples: crude patchouli oil, heavy fraction patchouli oil, and light fraction patchouli oil. Subsequently, the GC-MS analysis was conducted to compare the compound contents in samples. Our results indicate that the three patchouli oil samples have varying patchouli alcohol contents. Crude patchouli oil contains 31.2% patchouli alcohol; heavy fraction patchouli oil contains 61.82% patchouli alcohol, while light fraction patchouli oil contains 23.99% patchouli alcohol. This study demonstrates that heavy fraction patchouli oil has a greater potential as an antimicrobial compared to crude patchouli oil and light fraction patchouli oil.

Energy strategy alteration, rather than toxicity itself, interferes with the population fluctuation of Brachionus plicatilis exposed to water-accommodated fractions (WAFs) of crude oil

Oil spills are reported to have conflicting impacts of either injury or resilience on zooplankton communities, and physiological plasticity is speculated to be the possible causative factor. But how? An explanation was sought by exposing the marine rotifer Brachionus plicatilis to a series of water-accommodated fractions (WAFs) of crude oil under controlled laboratory conditions, and population dynamics, which is the core issue for zooplankton facing external stress, were analyzed. The total hydrocarbon concentration of WAFs was quickly degraded from a concentration of 5.0 mg L−1 to half within 24 h and then remained stable. No acute lethality was observed; only motion inhibition was observed in the group treated with 10 %, 50 % and 100 % WAFs, which occurred simultaneously with inhibition of feeding and filtration. However, sublethal exposure to the WAFs concentration series presented stimulation impacts on reproduction and even the population of B. plicatilis. The negative correlation between motion and reproduction seemed to indicate that a shift in the distribution of individual energy toward reproduction rather than motion resulted in increased reproduction after exposure to WAFs. More evidence from transmission electron microscopy (TEM) revealed ultrastructural impairment in both the ovaries and cilia in each treated group, and imbalance in mitochondrial numbers was one of the distinct features of alteration. WAFs stress may alter the energy utilization and storage paradigm, as indicated by the significant elevation in glycogen and the significant decrease in lipid content after WAFs exposure. Further evidence from metabolomics analysis showed that WAFs stress increased the level of lipid metabolism and inhibited some of the pathways in glucose metabolism. Sublethal acute toxicity was observed only in the first 24 h with WAFs exposure, and an energy strategy consisting of changes in the utilization and storage paradigm and reallocation is responsible for the population resilience of B. plicatilis during oil spills.

Qualitative Analysis of Nitrogen and Sulfur Compounds in Vacuum Gas Oils via Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry.

Analysis of the heavy fractions in crude oil has been important in petroleum industries. It is well known that heavy fractions such as vacuum gas oils (VGOs) include heteroatoms, of which sulfur and nitrogen are often characterized in many cases. We conducted research regarding the molecular species analysis of VGOs. Further refine processes using VGOs are becoming important when considering carbon recycling. In this work, we attempted to classify compounds within VGOs provided by Kuwait Institute for Scientific Research. Two VGOs were priorly distillated from Kuwait Export crude and Lower Fars crude. Quantitative analysis was performed mainly using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOFMS). MALDI-TOF-MS has been developed for analyzing high-molecular-weight compounds such as polymer and biopolymers. As matrix selection is one of the most important aspects in MALDI-TOFMS, the careful selection of a matrix was firstly evaluated, followed by analysis using a Kendrick plot with nominal mass series (z*). The objective was to evaluate if this work could provide an effective classification of VGOs compounds. The Kendrick plot is a well-known method for processing mass data. The difference in the Kendrick mass defect (KMD) between CnH2n-14S and CnH2n-20O is only 0.0005 mass units, which makes it difficult in general to distinguish these compounds. However, since the z* value showed effective differences during the classification of these compounds, qualitative analysis could be possible. The analysis using nominal mass series showed the potential to be used as an effective method in analyzing heavy fractions.