Size-Exclusion Chromatography of Asphaltenes: An Experimental Comparison of Commonly Used Approaches

Dong, Shen; Striegel, André M.

doi:10.1007/s10337-013-2472-0

Cited by 12 publications

(5 citation statements)

References 19 publications

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“…These changes in relative peak size (responses are normalized) indicate that as the concentration increases, most of the asphaltenes that are added to the solution go to the formation of aggregates. This behavior agrees with a previous study carried out at higher concentrations (down to 250 ppm) that shows an increase in molar masses as concentration increases . Similar to this study and others before, ,, the dilution effect of the chromatographic separation is not enough or fast enough to overcome the aggregation.…”

Section: Results and Discussionsupporting

confidence: 92%

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Evaluating Asphaltenes by Size Exclusion Chromatography

Rogel,

Dutta

2023

Energy Fuels

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Size exclusion chromatography (SEC) has been used extensively to characterize asphaltenes, crude oils, and petroleum products. These studies have provided significant insights into the nature and behavior of this material. This work presents a couple of new applications that use this technique. First, a new methodology is presented for determining the asphaltene content based on using a SEC column. This new method shows good repeatability, and the results correlate with the gravimetric standard method ASTM D6560. Second, we explored the SEC behavior of a series of different asphaltenes injected at low concentrations (10−500 ppm) using an evaporative light scattering detector. The analysis of the changes in relative areas of the peaks in the chromatogram revealed a break in the behavior between 50 and 100 ppm which could have been associated with the existence of a critical nanoaggregate concentration (CNAC). However, based on the presence of significant peaks (∼30−40% of the total area) corresponding to asphaltene aggregates even at concentrations as low as 10 ppm, this break cannot correspond to a CNAC, instead it might be associated with a transition to a different aggregation mechanism. This work also explores the SEC behavior of asphaltenes precipitated using different solvents from the same crude oil and shows how the aggregation is correlated to the solvent used to obtain the asphaltenes, while the aggregate sizes are related to the average characteristics of the molecules that precipitate using each solvent.

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Section: Results and Discussionsupporting

confidence: 92%

“…This behavior agrees with a previous study carried out at higher concentrations (down to 250 ppm) that shows an increase in molar masses as concentration increases . Similar to this study and others before, ,, the dilution effect of the chromatographic separation is not enough or fast enough to overcome the aggregation.…”

Section: Results and Discussionsupporting

confidence: 92%

Evaluating Asphaltenes by Size Exclusion Chromatography

Rogel,

Dutta

2023

Energy Fuels

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“…For the GPC analyses, a precise amount of sample (between 0.01 and 0.1 g) was weighted and an adequate mass of THF was added to reach a final concentration of 1% (100-fold mass dilution). At that concentration and in that solvent, there is aggregation within our samples , because we are well above the 500 ng/mL threshold described by McKenna et al and the dilution factor has an influence on the size distribution of those aggregates . However, on the basis of the work by Merdrignac et al using the same low dilution factor for all of our samples, we place ourselves in a “stable association state”, so that we can compare the size distributions obtained with similar aggregation conditions.…”

Section: Materials and Methodsmentioning

confidence: 52%

Study of the Size Distribution of Sulfur, Vanadium, and Nickel Compounds in Four Crude Oils and Their Distillation Cuts by Gel Permeation Chromatography Inductively Coupled Plasma High-Resolution Mass Spectrometry

et al. 2014

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The size distribution of sulfur, vanadium, and nickel was determined for four crude oils and their distillation cuts using gel permeation chromatography (GPC) coupled to inductively coupled plasma high-resolution mass spectrometry (ICP HR MS). The results show a trimodal distribution of vanadium and nickel compounds in the crude oils, the atmospheric residues, and the vacuum residues and, for sulfur compounds, either a mono- or bimodal distribution depending upon the distillation cut considered. A correlation exists between the sulfur fraction retention times and the temperature cuts of the distillation for a temperature below 560 °C and also between the viscosity of the crude oils and the proportion of trapped sulfur compounds in a higher boiling temperature fraction. The thermic treatment applied for the distillation increases the aggregation of low- and medium-molecular-weight compounds of vanadium and nickel into higher molecular weight aggregates between the crude oil on the one hand and the atmospheric residue and vacuum residue on the other hand, especially when the crude oil has a high total sulfur content.

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“…Its limited solubility represents a major hurdle for the chromatographic investigation and limits the method to solvents in which asphaltenes are soluble, such as toluene, dichloromethane, chloroform, and tetrahydrofuran. 17,18 Different separation methods have been used for analysis of asphaltene fraction, although not directly coupled to ultrahigh-resolution MS. Argentation chromatography (also known as silver ion chromatography) has been used since the 1960s mainly for investigation of lipids. 22,23 Nowadays, other applications, such as the separation of mixture of alkenes 24 and polycyclic aromatic hydrocarbons, 25 have become the focus of interest.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The most difficult crude oil fraction to study is the asphaltene fraction. Its limited solubility represents a major hurdle for the chromatographic investigation and limits the method to solvents in which asphaltenes are soluble, such as toluene, dichloromethane, chloroform, and tetrahydrofuran. , Different separation methods have been used for analysis of asphaltene fraction, although not directly coupled to ultrahigh-resolution MS. ,− …”

Section: Introductionmentioning

confidence: 99%

New Separation Approach for Asphaltene Investigation: Argentation Chromatography Coupled with Ultrahigh-Resolution Mass Spectrometry

Guricza

Schräder

2015

Energy Fuels

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Argentation chromatography has been developed for the analysis and separation of asphaltenes. The separation is based on the interaction between the silver ions (Ag⁺) bonded to a silica gel surface and the π-systems of the polycondensed aromatic compounds, where the interactions can be different when heteroatoms (N, O, S) are present in the molecules. Online coupling of argentation chromatography and high-resolution mass spectrometry allows fast and detailed analysis of the separation of crude oil asphaltenes. Highly condensed aromatic compounds possessing a high degree of unsaturation can be successfully separated using a mixture of toluene and chloroform (7:3 v/v) as mobile phase and dimethyl sulfoxide as competitive ligand for elution of asphaltene compounds with double bond equivalents (DBE) of up to 40. Making use of the different structural features of the components, it is possible to separate isomeric compounds that interact with different strengths with the stationary phase. The composition of mobile phase plays a significant role in separation efficiency

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Size-Exclusion Chromatography of Asphaltenes: An Experimental Comparison of Commonly Used Approaches

Cited by 12 publications

References 19 publications

Evaluating Asphaltenes by Size Exclusion Chromatography

Evaluating Asphaltenes by Size Exclusion Chromatography

Study of the Size Distribution of Sulfur, Vanadium, and Nickel Compounds in Four Crude Oils and Their Distillation Cuts by Gel Permeation Chromatography Inductively Coupled Plasma High-Resolution Mass Spectrometry

New Separation Approach for Asphaltene Investigation: Argentation Chromatography Coupled with Ultrahigh-Resolution Mass Spectrometry

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