Complex Mixture Of Hydrocarbons Research Articles

FtmsRanalysis: An R package for exploratory data analysis and interactive visualization of FT-MS data.

The high-resolution and mass accuracy of Fourier transform mass spectrometry (FT-MS) has made it an increasingly popular technique for discerning the composition of soil, plant and aquatic samples containing complex mixtures of proteins, carbohydrates, lipids, lignins, hydrocarbons, phytochemicals and other compounds. Thus, there is a growing demand for informatics tools to analyze FT-MS data that will aid investigators seeking to understand the availability of carbon compounds to biotic and abiotic oxidation and to compare fundamental chemical properties of complex samples across groups. We present ftmsRanalysis, an R package which provides an extensive collection of data formatting and processing, filtering, visualization, and sample and group comparison functionalities. The package provides a suite of plotting methods and enables expedient, flexible and interactive visualization of complex datasets through functions which link to a powerful and interactive visualization user interface, Trelliscope. Example analysis using FT-MS data from a soil microbiology study demonstrates the core functionality of the package and highlights the capabilities for producing interactive visualizations.

Formation of complex hydrocarbon systems from methane at the upper mantle thermobaric conditions

The existence of methane in the Earth’s mantle does not cause any doubt, however, its possible chemical transformation under the mantle thermobaric conditions is not enough known. Investigation of methane at the upper mantle thermobaric conditions, using diamond anvil cells, demonstrated the possible formation of ethane, propane and n-butane from methane, however, theoretical calculations of methane behaviour at extreme temperature and pressure predicted also heavier hydrocarbons. We experimentally investigated the chemical transformations of methane at the upper mantle thermobaric conditions, corresponding to the depth of 70–80 km (850–1000 K, 2.5 GPa), using “Toroid”-type Large reactive volume device and gas chromatography. The experimental results demonstrated the formation of the complex hydrocarbon mixture up to C7 with linear, branched and cycled structures and benzene. Unsaturated hydrocarbons were detected on the trace level in the products mixture. The increasing of exposure time leaded to growth of heavier components in the product systems. The data obtained suggest possible existence of complex hydrocarbon mixtures at the upper mantle thermobaric conditions and provide a new insight on the possible pathways of the hydrocarbons synthesis from methane in the upper mantle.

GC × VUV Study of Diesel: A Two-Dimensional Separation Approach

The characterization of complex hydrocarbon mixtures remains a challenging task. Advances in analytical characterization have been made in several fronts. One such advance is in gas chromatography–...

Innovative process for total petroleum hydrocarbons reduction on oil refinery sludge through microbubble ozonation

Oil refinery sludge is a complex mixture of hydrocarbons, water and sediments produced in the refining process, which is classified as a hazardous waste. The source reduction of sludge is inhibited by the combination of total petroleum hydrocarbons (TPH) and solid particles, and the decomposition of TPH is a critical step for oily sludge (OS) disposal. Microbubble ozonation was introduced to improve the efficiency for TPH removal in this work. 70.9% of TPH was found to be decomposed from OS with the initial pH of 3, ozone dosage of 0.27 gO3/gTS and total solid of 2% in 120 min. The corresponding reaction rate constant k for the rapid stage reached 0.0269 min−1, two times higher than the control system of macrobubble ozonation. The synergistic effect of oxidation and flotation was observed in the microbubble system by destroying the chemical bonds between petroleum hydrocarbons and particle surface and improving the adhesion probability between microbubbles and oily flocs. A broad-spectrum removal rate of 71.7–79.5% was observed for the middle or long chain hydrocarbons fractions (nC7-C10, nC11-C20, nC21-C30 and nC31-C40) in TPH. Most of heavy hydrocarbons (nC21-C40) in OS were oxidized and decomposed to the low boiling point hydrocarbons according to thermogravimetric results. The principal intermediates included 42.6% carboxylic acids, 18.8% phenolics and 13.9% alcohols and other gaseous byproducts. Microbubble ozonation is expected to be the first step for detoxification and decomposition of OS, thus reducing the generation of hazardous wastes.

Efficient biodegradation of petroleum n-alkanes and polycyclic aromatic hydrocarbons by polyextremophilic Pseudomonas aeruginosa san ai with multidegradative capacity.

Pseudomonas aeruginosa san ai, an alkaliphilic, metallotolerant bacterium, degraded individual selected petroleum compounds, i.e., n-alkanes (n-hexadecane, n-nonadecane) and polycyclic aromatic hydrocarbons (fluorene, phenanthrene, pyrene) with efficiency of 80%, 98%, 96%, 50% and 41%, respectively, at initial concentrations of 20 mg L−1 and in seven days. P. aeruginosa san ai showed a high biodegradative capacity on complex hydrocarbon mixtures, the aliphatic and aromatic fractions from crude oil. The efficiency of P. aeruginosa san ai degradation of crude oil fractions in seven days reached stage 3–4 of the oil biodegradation scale, which ranges from 0 (no biodegradation) to 10 (maximum biodegradation). Identified metabolites concomitant with genomic and enzymatic data indicated the terminal oxidation pathway for the n-alkane degradation, and the salicylate and phthalate pathways for fluorene biodegradation. Polyextremophilic P. aeruginosa san ai, as a biosurfactant producer with multidegradative capacity for hydrocarbons, can be used in an improved strategy for environmental bioremediation of hydrocarbon-contaminated sites, including extreme habitats characterized by low or elevated temperatures, acidic or alkaline pH or high concentrations of heavy metals.

La complejidad química de las gasolinas de automoción

Utilizadas principalmente como combustibles en motores de combustión interna, las gasolinas son mezclas complejas de hidrocarburos que incluyen en su composición distintos aditivos para mejorar su estabilidad y prestaciones. Su composición química es no solo diversa, sino también variable, dependiendo del crudo de procedencia, del proceso de obtención y de las normativas existentes. Estas fijan el contenido máximo permitido de determinados compuestos que, por su toxicidad, deben quedar limitados. Las gasolinas se obtienen por destilación fraccionada del petróleo y también a partir de fracciones más pesadas del mismo, mediante craqueo térmico o catalítico, procesos que junto al reformado catalítico van a tener una incidencia directa en su composición. El objetivo de esta revisión es abordar la compleja composición que presentan las gasolinas, así como algunos procesos básicos del refinado de petróleo. Estos procesos determinan en buena medida la naturaleza química de los componentes de este combustible, algunos de los cuales se relacionan con la emisión de sustancias nocivas para la salud y el medio ambiente. De esta forma, proporcionamos un contexto más exacto sobre los agentes contaminantes de la gasolina, a la vez que ponemos de manifiesto la necesidad de contar con normativas avanzadas que regulen la composición de los combustibles.

Evaluation of immunological, inflammatory, and oxidative stress biomarkers in gasoline station attendants

BackgroundGasoline is a complex mixture of saturated and unsaturated hydrocarbons, in which aromatic compounds, such as BTX (benzene, toluene, and xylene) feature as the main constituents. Simultaneous exposure to these aromatic hydrocarbons causes a significant impact on benzene toxicity. In order to detect early alterations caused in gasoline station attendants exposed to BTX compounds, immunological, inflammatory, and oxidative stress biomarkers were evaluated.MethodsA total of 66 male subjects participated in this study. The gasoline station attendants (GSA) group consisted of 38 gasoline station attendants from Rio Grande do Sul, Brazil. The non-exposed group consisted of 28 subjects who were non-smokers and who had no history of occupational exposure. Environmental and biological monitoring of BTX exposure was performed using blood and urine.ResultsThe GSA group showed increased BTX concentrations in relation to the non-exposed group (p < 0.001). The GSA group showed elevated protein carbonyl (PCO) levels and pro-inflammatory cytokines, decreased expression of CD80 and CD86 in monocytes, and reduced glutathione S-transferase (GST) activity compared to the non-exposed group (p < 0.05). BTX levels and trans,trans-muconic acid levels were positively correlated with pro-inflammatory cytokines and negatively correlated with interleukin-10 contents (p < 0.001). Increased levels of pro-inflammatory cytokines were accompanied by increased PCO contents and decreased GST activity (p < 0.001). Furthermore, according to the multiple linear regression analysis, benzene exposure was the only factor that significantly contributed to the increased pro-inflammatory cytokines (p < 0.05).ConclusionsTaken together, these findings show the influence of exposure to BTX compounds, especially benzene, on the immunological, inflammatory, and oxidative stress biomarkers evaluated. Furthermore, the data suggest the relationship among the evaluated biomarkers of effect, which could contribute to providing early signs of damage to biomolecules in subjects occupationally exposed to BTX compounds.

Chemical Composition and Antimicrobial Activity of Bark and Leaf Extracts of Cupressus sempervirens and Juniperus phoenicea Grown in Al- Jabel Al-Akhdar Region, Libya

Background:Plant extracts are important products in the world and have been widely used for isolation of important biologically active products. Because of their significant environmental impact, extensive research has been explored to determine the antimicrobial activity of plant extracts.Methods:Acetone extracts of the bark and leaf of Cupressus sempervirens and Juniperus phoenicea, collected from three different altitudes (125, 391, and 851 m high of sea level) at Al- Jabel Al-Akhdar area, Libya were obtained and analyzed by GC/MS. The antimicrobial activity of the extracts was further evaluated against plant bacteria Rhizobium radiobacter, Erwinia carotovora, Rhodococcus fascians and Ralstonia solanacearum and fungus Botrytis cinerea.Results:The impact of the altitude from the sea level on the quantity and chemical constituents of the extracts was investigated. The yield was largely dependent on tree species and the highest yield (6.50%) was obtained with C. sempervirens L bark of altitude III (851 m of the sea level), while the lowest (1.17%) was obtained with the leaf extract of C. sempervirens L from altitude I (125 m). The chemical composition analyzed by GC/MS confirmed that the leaf extracts of C. sempervirens and J. phoenicea contained a complex mixture of monoterpene hydrocarbons, sesquiterpenes, diterpenes, diterpenoids, terpenophenolic, steroids and phthalates. However, the bark extracts of both trees contained a mixture of sesquiterpenes, diterpenes, diterpenoids, terpenophenolics, phthalates, retinol and steroids. These constituents revealed some variability among the extracts displaying the highest interesting chemotype of totarol (terpenophenolic) in all extracts (14.63-78.19% of the total extract). The extracts displayed a noteworthy antifungal potency with varying degrees of inhibition of growth with EC50 values ranged from 78.50 to 206.90 mg/L. The extracts obtained from the leaves of C. sempervirens showed that the highest inhibitory activity was obtained with the extract of altitude II (391 m) with MIC 565, 510, 380 and 710 mg/L against E. carotovora, R. fascians, and R. radiobacter and R. solanacearum, respectively.Conclusion:Based on antimicrobial activity, raw plant extracts can be a cost-effective way to protect crops from microbial pathogens. Because plant extracts contain several antimicrobial compounds, the development of resistant pathogens can be delayed.

Effect of Reaction Conditions on Catalytic and Noncatalytic Lignin Solvolysis in Water Media Investigated for a 5 L Reactor.

The high content of oxygen in the lignin polymer and the prevalence of phenolic functional groups make the conversion of lignin to fuels and value-added products with well-defined chemical properties challenging. The lignin-to-liquid process using a water/formic acid reaction medium has been shown to convert the lignin polymer to monomers with a molecular weight range of 300–600 Da. The bio-oil comprises a complex mixture of monomeric phenols, aromatics, and aliphatic hydrocarbons with a high H/C and low O/C ratio. This study investigates the effect of the stirring rate, level of loading, and catalyst at 305 and 350 °C in a 5 L pilot scale reactor. The oil yields are found to be highest for experiments conducted using the maximum stirring rate, maximum level of loading, and Ru/Al2O3 catalyst with yields of more than 69 wt % on lignin intake. Goethite as a catalyst does not show good conversion efficiency at either reaction temperatures. The carbon recovery is highest for products produced at 305 °C. Furthermore, results from solid phase extraction on a DSC-CN solid phase show that 65–92 wt % the bio-oils can be recovered as fractions separated based on polarity.

Thiophene Determination in Liquid Hydrocarbons by In-line Acoustic Measurements

Introduction.Petroleum is a complex mixture of hydrocarbons. Sulphur is the most common heteroatom in pe-troleum and petroleum products. Its content in oil can reach 14 %. The determination of sulphur in oil and its removal is of great importance, since sulphur compounds adversely affect the quality of petroleum products and pollute the environment. Desulphurization of hydrocarbons is important in the processing of petroleum products, which needs in usage of accurate and simple methods for the sulphur-containing components determination. Most of developed methods are difficult to apply for flow online analysis, which can create difficulties in using them to monitor the content of sulphur-containing heteroatomic components in real time. Acoustic sensors are one of the possible solutions. In term of sensing of flammable liquids, the use of the acoustic methods is attractive since the analyte is not a part of an electrical measuring circuit and it is only acoustically coupled that prevents an occurrence of a spark.Objective.The purpose of the work is to study the possibilities of online flow analysis of sulphur-containing heteroatomic components using acoustic measurements. The challenge is the development of a resonator system integrated with the pipe.Materials and methods. Thiophene and oil fraction with the boundary boiling point of 100–140 oC were used to prepare the mixtures. Thiophene is a representative of sulphur-containing components, which may be included in the composition of petroleum and its derivatives. Experimental measuring equipment includes impedance analyzer, a developed sensor structure integrated with a liquid-filled pipe, a pump and a tank with a measured liquid. A theoretical analysis of sensor structure was carried out on the basis of numerical simulation using COMSOL Multiphysics software.Results.The sensor structure was designed as a combination of 2D and 1D pipe periodic arrangements to achieve high Q-factor of acoustic resonance in the flow system. The eigenmodes of the sensor structure with a liquid analyte were carried out. The characteristic of sensor structure is determined. The sensor shows good sensitivity to the thiophene content with high resolution in-line analysis. This result is achieved by limiting the energy losses of acoustic resonance in radiation along the pipe by creating a periodic structure.Conclusion. The study of acoustic properties of solutions prepared on the basis of thiophene and oil fraction with boundary boiling point 100–140 °C was performed. It shows that methods based on acoustic spectroscopy make it possible to accurately determine the concentration of heteroatomic components in gasoline mixtures, since the presence of heteroatomic components leads to a change in mechanical properties of liquid hydrocarbons mixtures. Possible applications for developed acoustic sensor are flow analysis for monitoring the quality of oil products.

Complex multicomponent real-fluid thermodynamic model for high-pressure Diesel fuel injection

The Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) has been coupled with Vapor-Liquid Equilibrium (VLE) calculations in a density-based solver of the Navier-Stokes equations to perform multicomponent two-phase simulations of Diesel injections at high-pressure conditions. This molecular-based EoS requires three empirically determined but well-known parameters to model the properties of a specific component, and thus, there is no need for extensive model calibration, as is typically the case when the NIST (REFPROP) library is utilised. PC-SAFT can handle flexibly the thermodynamic properties of multi-component mixtures for which the NIST (REFPROP) library supports only limited component combinations. Moreover, complex hydrocarbon mixtures can be modelled as a single pseudo-component knowing its number averaged molecular weight (MW) and hydrogen-to-carbon (HN/CN) ratio. Published molecular dynamic simulations have been utilised to demonstrate that the developed algorithm properly captures the VLE interface at high-pressure conditions. Several advection test cases and shock tube problems were performed to validate the numerical framework using analytical and exact solutions. Additionally, two-dimensional simulations of n-dodecane and Diesel injections into nitrogen are included to demonstrate the multidimensional, multispecies and multiphase capability of the numerical framework.

Supercritical fluid extraction of bitumen using chemically modified carbon dioxide

Surface minable oil sands are a significant source of heavy oil (bitumen) production in Canada. Supercritical fluid extraction (SFE) provides a potential means to recover bitumen, a complex mixture of hydrocarbons, from process and process waste streams generated during the extraction and processing of bitumen from surface mined oil sands. Dynamic extractions were conducted to determine the effect of two modifiers, toluene and methanol, on the extraction of hydrocarbons from bitumen using carbon dioxide (CO2) at supercritical conditions of 24 MPa and 333 K. Toluene was tested at concentrations of 5, 10 and 15 mol% whereas methanol was tested at these concentrations plus at 33.7 mol% in supercritical CO2 (SC-CO2). High temperature simulated distillation (HTSD) was used to determine the distillation profile of the extracted hydrocarbons. SC-CO2 only extracted 39 wt% of the bitumen while a methanol concentration of 33.7 mol% in SC-CO2 extracted 55 wt% and 15 mol% toluene in SC-CO2 extracted 76 wt% of the bitumen. Higher modifier concentrations lead to increased extraction efficiencies. Toluene consistently extracted more hydrocarbons than methanol. The hydrocarbons extracted when toluene was used as a modifier were consistently the heaviest hydrocarbon mixtures, with higher toluene concentrations increasing this compositional effect.

Influence of exposure dose, complex mixture, and ultraviolet radiation on skin absorption and bioactivation of polycyclic aromatic hydrocarbons ex vivo.

Combined exposure to complex mixtures of polycyclic aromatic hydrocarbons (PAHs) and ultraviolet radiation (UVR) is suspected to enhance PAH skin permeability and skin cancer risk depending on PAH bioactivation. The impact of PAH mixtures (exposure dose, composition, and complexity) and UVR was assessed for PAH cutaneous absorption and metabolism using realistic exposure conditions and human skin explants. PAH complex mixtures were extracted from the industrial products coal tar pitch (CTP-I) and petroleum coke (PC-I). The synthetic mixture (CTP-S) was identically reconstituted using PAH standards. The applied dose was adjusted to 1 (PC-I, CTP-I) or 10nmol (CTP-I, CTP-S) of benzo[a]pyrene (B[a]P). Unmetabolized PAHs were recovered from the skin surface, skin and medium, and then quantified by HPLC-fluorescence detection. PAH metabolites were collected from the medium and analyzed by GC-MS/MS. B[a]P and PAH penetration was lower for the highest B[a]P dose, industrial mixtures, and CTP-I compared to PC-I. Skin irradiation increased PAH penetration only for CTP-I. PAH uptake was poorly influenced by the different experimental conditions. PAH metabolism markedly decreased in the application of mixtures, leading to unmetabolized PAH accumulation in human skin. PAH metabolism was similar between CTP-I and PC-I, but was lower for the highest dose and the industrial mixtures, suggesting a saturation of xenobiotic metabolizing enzymes, as confirmed in a time-course study. UVR strongly inhibited all PAH metabolism. Altogether, these results underline the necessity to consider the reality of human exposure (PAH complex mixtures and UVR) during in vitro experiments to properly estimate skin absorption and metabolism.

Asthma vs. PM2.5: A Bridge Between Health and Environmental Surveillance.

Asthma vs. PM2.5: A Bridge Between Health and Environmental Surveillance.

Flex-fuel engine: Influence of ethanol content on power and efficiencies

Gasoline is a complex mixture of different hydrocarbons, with a wide spectrum of constituents. Surrogate fuels have a reduced number of chemical components and therefore are used to model commercial fuels and enhance the understanding of fuel behavior in internal combustion engines. Surrogates also allow better fuel property control. In previous work, a surrogate fuel blend of iso-octane, n-heptane, toluene and ethanol was found to be suitable for commercial, high-octane, oxygenated Brazilian gasoline. This article investigates the influence on a Flex-fuel engine power and efficiencies of different ethanol levels in this surrogate fuel blend. The study found some different trends when comparing to other works in the literature. This article intends to make contributions presenting more detailed analyses of how fuel properties can influence several Flex-fuel engine performance parameters.

Identification of metal porphyrins in Duri crude oil

Crude oil comprises several complex hydrocarbon mixtures because of their slow natural formation process, including the toluene-soluble asphaltene component. The comparison result of Soxhlet extraction with and without silica was 55.15% and 86.75%, respectively. The Duri crude oil residue is mixed with silica gel, and Soxhlet extraction was performed with toluene. Further Soxhlet extractions and purifications obtain free porphyrin and two metal porphyrins. The Fourier Transform Infrared (FTIR) spectrum of n-heptane column chromatographic separation indicated the presence of a pyrrole ring at wavenumber 800 cm−1 in the fingerprint region as a porphyrin-formed group. UV-Vis absorption spectra of the n-heptane separation showed free porphyrin spectra at a maximum wavelength of 440 nm and those of metal porphyrins ranging 500−700 nm. The results of qualitative analysis of toluene fraction and n-heptane fraction showed the presence of C, Si, S, Ni, V, Fe, and Al. With this combination of spectroscopic techniques (FTIR, UV-Vis), Liquid Chromatography-Mass Spectrometry (LC-MS), and Energy Dispersive X-Ray Spectroscopy (EDX), nickel porphyrin (C32H36N4Ni, 534 m/z) and etioporphyrinato vanadyl (IV) (C32H36N4VO, 541 m/z) are isolated and identified from the silica gel chromatography fraction of the n-heptane Soxhlet extract of the toluene Soxhlet extract obtained from the Duri crude oil residue.

Superoleophilic Magnetic Iron Oxide Nanoparticles for Effective Hydrocarbon Removal from Water

AbstractVarious hydrocarbons are efficiently extracted from water by using a new sorbent material based on covalently functionalized magnetic nanoparticles. The functionalization of the magnetite nanoparticles with a self‐assembled monolayer of hexadecylphosphonic acid renders the nanoparticles oleophilic and the magnetic nature of magnetite allows for simple extraction of the hydrocarbon‐soaked sorbent. The sorbent material is capable of extracting single contaminants such as alkanes and aromatics and complex hydrocarbon mixtures such as crude oils in high extraction rates of up to 14 times the sorbent volume. Experimental results are explained by molecular dynamics simulations on the adsorption of single components from a hydrocarbon‐water mixture to the alkylphosphonic acid layer on the nanoparticles. The core–shell sorbent material is highly stable and therefore, reusable over several successive extraction cycles without degradation. The extraction performance is determined at different water temperatures, different water sources, and different magnetic core materials and evaluated compared to heptadecanoic acid functionalized magnetite. The new sorbent material provides the opportunity for an efficient, reliable, inexpensive, and environmental friendly removal of hydrocarbons from water.

Life Cycle of Wash Oil for Benzol Absorption from Coke Oven Gas

AbstractAn important source of benzol is coke oven gas, which is a by‐product of metallurgical coke production. A cycle of absorption into the washing oil and reverse desorption is a crucial step in this technology. The wash oil itself is a complex mixture of hydrocarbons with higher boiling point. Its washing property is changing during time of use. The concentration of unabsorbed benzene in the coke oven gas leaving the absorption is monitored as an indicator of the washing oil condition. A secondary parameter is the viscosity of the washing oil. The optimal operating conditions of the absorption unit of benzol and the ranges of physical properties, which mainly influence the benzol absorption, were identified. Beside the increasing absorption efficiency, it is significant to prolong the life cycle of wash oil.

Recycling of lubricating oils used in gasoline/alcohol engines

Lubricating oils are complex mixtures of hydrocarbons obtained from petroleum by refining process and represent 2% of petroleum derivatives. The used lubricating oil is an important raw material for re-refining, because during its use it is not completely degraded, so it can be recovered from it, the base oil, which can be reused for the same purpose. Mineral-based lubricating oils were used for this work. It worked with two engines using the same type of oil; one of them was monitored during approximately 5000 km and the other one for 10,000 km. The base oil was then recovered from the lubricant using polar organic solvents (1-butanol, 2-propanol and methyl-ethyl-ketone) and then characterized by physicochemical analysis and thermal analysis (TG/DTG/DTA). From the solvents used in the extraction of the base oil, the best yields were methyl-ethyl-ketone, about 80% and 1-butanol, just above 70%. Already with 2-propanol, it was not satisfactory. The method used for the recovery of waste oils proved to be feasible and, the thermal analysis techniques evidenced the viability of this process.

Electronic nose for smart identification of roofing and paving grade asphalt

Abstract Asphalt is a complex mixture of hydrocarbons, whose properties strongly depend on the source and type of crude oil and refining processes. From a technical standpoint, intensive investigations carried out by the construction sector, above all by road researchers, have attempted to understand relationships between asphalt binder chemical structure, morphology and physical characteristics. Nevertheless, one challenge that the advance research on asphalt products actually face is to transfer this extremely high level of knowledge to applied industrial technologies for finding easy-to-use, quick and cost-effective test methods for quality control and identification of asphalt binders at refinery, terminal and plant. Thus, this paper focused on the development of a protocol for fingerprinting, including identification and discrimination, of asphalt cements using two different electronic noses (e-noses), also known as artificial olfactory systems (AOS). E-nose is a biomimetic non-destructive intelligent sensing instrument, which is designed to mimic the human sense of smell to detect, compare and classify odor sample, producing a qualitative output (fingerprint). Results suggested that a complementary combination of electronic nose technique and well-established analytical methodologies could be successfully used for the identification and discrimination of roofing and paving grade asphalt cements. Specifically, both sensing instruments were able to perform a good discrimination between products characterized by a different chemical nature and to verify the refinery process stability during production and a batch-to-batch crude oil consistency.