Non-aqueous Extraction Research Articles

Smectite-bitumen interactions in non-aqueous bitumen extraction process

The non-aqueous extraction (NAE) is an alternative to the commercial water-based extraction technology used to liberate bitumen from oil sands. Although the impact of kaolinite, illite, chlorite, illite-smectite and montmorillonite on NAE process has been previously studied, the effect of different types of smectites has not been fully understood yet. In this work, mixtures of bitumen with bentonites dominated by saponite, hectorite, nontronite, beidellite and montmorillonite were reacted for several days and then washed with solvent (cyclohexane) to remove bitumen from the bentonites. The main goal was to better understand the impact of different smectites properties (specific surface area, pore structure characteristics, particle size, crystallite thickness, swelling ability, cation exchange capacity, layer charge and crystal-chemistry of smectites) on NAE process. The results showed that the porosity, particle size and swelling ability were the key parameters affecting the solvent-based bitumen recovery under the studied conditions. Samples with larger initial total pore volume and smaller particle size displayed reduced solvent bitumen extractability. The particle size of studied samples was affected primarily by swelling of smectites during the solvent bitumen extraction experiments. Smectites were swelling in water but not in cyclohexane. Swelling of smectite caused splitting of larger clay particles into many smaller particles. As a consequence, the efficiency of solvent bitumen extraction was significantly lower for fine grained samples, consisting of thin delaminated smectite particles, in which the bitumen was distributed among small-sized clay particles.

Effect of ore quality on non‐aqueous oil sand extraction performance

AbstractCurrent commercial aqueous based extraction processes are energy and greenhouse gas (GHG) intensive and require large tailings ponds. Non‐aqueous extraction (NAE) of bitumen from mineable oil sands is an alternative that eliminates tailings ponds with potentially lower energy requirements and GHG emissions. The economics of the NAE process depend partly on the impact of ore quality on bitumen recovery and product quality (low water and solids content). It has been claimed that NAE performance is insensitive to the quality (bitumen content) of the oil sand ores. However, the available data are ambiguous because different extraction methods and solvents were used in different studies and, in many cases, a limited range of ore qualities was examined. In this study, bitumen was extracted from eight ores of different quality with cyclohexane using a multistage method equivalent to a countercurrent process with a solvent/ore ratio of 0.67 w/w. The bitumen recovery and the water and solids content of the product bitumen were determined for each ore. It was found that bitumen recovery correlated negatively to clay content of the ore. The loss of recovery was attributed to bitumen adsorption on clays. The product quality was insensitive to the ore quality and instead depended on the density of the fluid medium, as expected with a centrifuge‐based separation method. The recovery and product quality from the NAE method were similar to those from aqueous extractions.

Effective recovery of bitumen from Jordanian tar sand using several extraction methods

ABSTRACT The study aims to characterize the structural features of Jordanian tar sand using analytical techniques including (FTIR, ultimate and proximate analysis, TGA, XRD, and XRF). The tar sand shows a low content of volatile matter (bitumen) with significant nitrogen content. The bitumen contains a high proportion of aliphatic hydrocarbons of which high content of it attached to oxygen atom. The minerals were mainly quartz and low concentration of carbonate with noticeable content of sulfite and potassium oxide from XRF. The recovery of bitumen was evaluated using three different extraction techniques: solvent extraction methods (ultrasound-assisted extraction, non-aqueous extraction) and thermal pyrolysis using the Fischer assay apparatus. The non-aqueous solvent extraction method gave the highest bitumen recovery using toluene as a solvent; however, the high-temperature Fischer assay method provided a low recovery. The extracted bitumen under the optimum condition was characterized using NMR, elemental analysis, and GC-MS analysis. The oil products from tar sand showed a high concentration of oxygen and noticeable concentration of sulfur atoms. The 1H-NMR revealed a high content of aliphatic hydrocarbons in good agreement with raw tar sand characteristics. The identified compounds in the GC-MS where mainly substituted with oxygen atom in the form of alcohols and ethers.

Probing the Interaction Forces between Bitumen-Coated Mineral Surfaces with Implications for the Removal of Fine Solids from Oil Product: Effect of Solvent

Summary Considerable amounts of fine solids retained in the bitumen product have been a significant challenge hindering the commercialization of nonaqueous extraction (NAE) of bitumen from oil sands. Understanding the surface interaction between bitumen-coated fine particles and the suspension stability in NAE bitumen products is essential for developing suitable solutions to remove these undesired particles. In this work, the adsorption behaviors of bitumen on a model clay surface (i.e., molecularly smooth mica surface) in organic solvents (i.e., cyclohexane and cyclohexane-heptane mixtures) were systematically investigated using a surface force apparatus (SFA). Furthermore, the interaction forces between bitumen-coated mica surfaces were directly measured in different organic solvents to reveal the stabilization mechanism of fine solids during the NAE process. It was found that the solvent type and adsorption time significantly affect the adsorption behavior of bitumen on mica surface and regulate the interaction forces between bitumen-coated mica surfaces, which in turn have an impact on the stability of suspended fine solids in solvents. In cyclohexane or cyclohexane-rich solution, a thin layer of bitumen (~5 nm) was quickly deposited on fresh mica surface within 5 minutes and gradually equilibrated to form a soft layer after a long process (>40 minutes). Only pure repulsive force due to steric repulsion was measured between the adsorbed layers, which led to a stable suspension of fine solids in solvents. In contrast, the presence of heptane caused the bitumen to rapidly (<20 minutes) form a compact packing adsorption layer, and a weak adhesive force (<5 mN/m) was measured between the bitumen-coated surface during the separation process. The adhesive force could be mainly brought by the interpenetration of long hydrocarbon chains or the conformation change of the organic network in both solution and substrate surface, which could lead to aggregation and settling of fine solids. Our SFA results provide valuable insights into the adsorption behavior of bitumen onto mineral surfaces and the interaction mechanism of bitumen-coated mineral surfaces in organic media, with important implications for the removal of fine solids from oil products.

Removal of fine solids from bitumen by hetero-aggregation and magnetic separation using surface-modified magnetite nanoparticles. Part 1: Proof of concept

Separation of fine particles suspended in liquid is crucial yet difficult and inefficient in various engineering processes. In the oil sands industry, high fine solids content in produced bitumen is one of the hurdles preventing non-aqueous extraction (NAE) from being used in commercial operations. This work proposed a novel method for fine solids removal from NAE bitumen by hetero-aggregation with surface-modified magnetite nanoparticles followed by magnetic separation. Stearylamine acetate-functionalized magnetite nanoparticles (SAA-MNPs) were prepared and characterized, and the separation performance of fine solids from NAE bitumen by the proposed approach using SAA-MNPs was quantitatively evaluated and compared with un-modified magnetite nanoparticles (MNPs). It is demonstrated that after functionalization with SAA, the separation effectiveness was significantly improved. Hetero-aggregates between the NAE fine solids and SAA-MNPs were shown to be formed in cyclohexane. The present work provided a promising approach of combining hetero-aggregation and magnetic separation for the purification of hydrocarbon products such as Alberta oil sands bitumen.

High molecular weight guar gum assisted settling of fine solids in diluted bitumen: Effect of solvents

As water-based extraction technologies for producing bitumen from oil sands have received increasing environmental concerns, developing non-aqueous extraction (NAE) technique is of both fundamental and practical importance. However, the relatively high concentration of fine solids trapped in the extracted bitumen presents an obstacle for pipeline transport as well as upgrading and refining downstream. This research attempts to provide a solution to fine solids removal without using synthetic additives or affecting bitumen recovery from NAE process. Herein, naturally hydrophilic additives (i.e., water and high molecular weight guar gum (HGG) produced from Cyamopsiste tragonolobuosr L. Taup.) were introduced to promote the settling of fine solids suspended in bitumen-solvent solution, and the effects of solvents (i.e., toluene, cyclohexane and their mixtures) were systematically investigated. Aggregate size distribution analyzed by the focused beam reflectance measurements confirmed that the addition of water and HGG could promote the agglomeration and settling of fine solids in all solvents studied. However, the size range and quantity of the agglomerates vary significantly with the solvent's aromatic character. Solvent mixtures demonstrate a superior performance on removing fine solids from bitumen over single solvent. Specifically, in a 3:2 toluene/cyclohexane mixture, the solid content was lowered from 0.66 wt% to 0.09 wt%.

Factors influencing non-aqueous extraction process of bitumen to mitigate the environmental impacts

Environmental pollutants' transport through tailing extraction process is a big challenge. Hazardous materials in tailings ponds increase with high negative environmental impacts. In this paper, a new type of bench no-water-extracted bitumen process was developed. Factors such as three oil sand ores, namely high, medium, and low-grade in the Athabasca deposits have been exposed to five different light hydrocarbon solvents. The bitumen recovery efficiency of the novel system was investigated with respect to solvent-to-bitumen ratios (S/Bs) as well as solvent and ore properties. The results showed that this novel bench-scale non-aqueous extraction process could significantly reduce water consumption and improve solvent recycling and reduce the release of major hazardous chemicals to oil sands tailings water. The new solvent recovery and bitumen quality for all treated ores were as good as the outcomes from hot water leaching and naphtha froth treatment. When low boiling point solvents (especially cyclopentane) are used to treat high grade ores, the efficiency of bitumen recovery was able to reach over 99 % wt % (by weight %). At the same time, the solvent loss rate could be controlled below 4 barrels (bbl) of solvent per 1000 bbl of extracted bitumen (0.4 %). This indicates the evident effectiveness of non-aqueous extraction of bitumen to mitigate the environmental impacts.

Understanding the Complex Surface Interplay for Extraction: A Molecular Dynamics Study.

By means of classical molecular dynamics simulation the interfacial properties of methanol and n‐dodecane, which are two potential candidate solvents for use in non‐aqueous liquid–liquid extraction, were assessed. The question of how the interface changes depending on the concentration of extractant (tri‐n‐butyl phosphate) and salt (LiCl) is addressed. Two different models to represent systems were used to evaluate how LiCl and tri‐n‐butyl phosphate affect mutual miscibility, and how the last‐named behaves depending on the chemical environment. Tri‐n‐butyl phosphate increases the mutual solubility of the solvents, whereas LiCl counteracts it. The extractant was found to be mostly adsorbed on the interface between the solvents, and therefore the structural features of the adsorption were investigated. Adsorption of tri‐n‐butyl phosphate changes depending on its concentration and the presence of LiCl. It exhibits a preferential orientation in which the butyl chains point at the n‐dodecane phase and the phosphate group points at the methanol phase. For high concentrations of tri‐n‐butyl phosphate, its molecular orientation is preserved by diffusion of the excess molecules into both the methanol and n‐dodecane phases. However, LiCl hinders the diffusion into the methanol phase, and thus increases the concentration of tri‐n‐butyl phosphate at the interface and forces a rearrangement with subsequent loss of orientation.

Destabilization of bitumen-coated fine solids in oil through water-assisted flocculation using biomolecules extracted from guar beans

Non-aqueous extraction (NAE) of bitumen from oil sands has been gaining great attention from both the industry and academia as an alternative to the water-based extraction. A fine solids removal step is important for a NAE process in order to obtain high-quality bitumen product, which, however, remains a great challenge to reduce the fine solids content to the desired level. Here, we introduce a strategy of destabilizing the bitumen-coated silica particles in toluene with the addition of water and biomolecules extracted from Cyamopsiste tragonolobuosr L. Taup., i.e., high molecular weight guar gum (HGG) and low molecular weight guar gum (LGG), respectively. By virtue of sedimentation tests and focused beam reflectance measurement analysis, we demonstrate that the introduced water droplets modified with these biomolecules can facilitate the settling of the solid particles in toluene although the underlying mechanisms differ between these two biomolecule cases. Specifically, in the case of LGG, the added water droplets with the interfacial amphiphilic LGG can strengthen the attachment of solid particles from bulk toluene to the LGG surface. This research work provides useful insight into the development of effective approaches for destabilization and removal of bitumen-coated fine solids from NAE bitumen.

Extraction of Lipids from Liquid Biological Samples for High-Throughput Lipidomics.

Extraction of the lipid fraction is a key part of acquiring lipidomics data. High-throughput lipidomics, the extraction of samples in 96w plates that are then run on 96 or 384w plates, has particular requirements that mean special development work is needed to fully optimise an extraction method. Several methods have been published as suitable for it. Here, we test those methods using four liquid matrices: milk, human serum, homogenised mouse liver and homogenised mouse heart. In order to determine the difference in performance of the methods as objectively as possible, we used the number of lipid variables identified, the total signal strength and the coefficient of variance to quantify the performance of the methods. This showed that extraction methods with an aqueous component were generally better than those without for these matrices. However, methods without an aqueous fraction in the extraction were efficient for milk samples. Furthermore, a mixture containing a chlorinated solvent (dichloromethane) appears to be better than an ethereal solvent (tert-butyl methyl ether) for extracting lipids. This study suggests that a 3:1:0.005 mixture of dichloromethane, methanol and triethylammonium chloride, with an aqueous wash, is the most efficient of the currently reported methods for high-throughput lipid extraction and analysis. Further work is required to develop non-aqueous extraction methods that are both convenient and applicable to a broad range of sample types.

Efficient recovery of extra-heavy oil using a naturally abundant green solvent: Toward a more sustainable oil-solid-water separation

Non-aqueous extraction (NAE) at ambient temperature is a promising substitute to the current commercial hot water process for mined oil sand, but several challenges remain largely due to the use of hazardous conventional organic solvents (COS) such as toluene or heptane. In this work, a more sustainable process for separating extra-heavy oil from oil sands ore using β-pinene, a naturally abundant green solvent was developed. The method used to facilitate phase separation was two-stage centrifugation. Experimental parameters investigated included centrifugal force, solvent dosage and extraction time. Results indicated that oil recovery and supernatant product quality using β-pinene were affected by these process parameters, but there was little to no sensitivity to the grade of ore tested. The β-pinene extraction, after two stages of centrifugation, achieved oil recoveries of 96% to 99% for different-grades of ore, the highest yield compared to those often obtained using either toluene or n-heptane. The total water and solids content in the supernatant of the β-pinene extract could be controlled to 0.09 wt% and this is comparable to extraction by toluene. Importantly, the quantity of β-pinene solvent residual in sand after evaporation, although inversely relating to oil recovery, was limited in the range of about 5 to 60 ppm, a level well below the regulation target for a COS. The application of β-pinene solvent as a green alternative in NAE could reduce the safety, environmental, and health concerns associated with the use of a COS.

Multistage aqueous and non-aqueous extraction of bio-molecules from microalga Phaeodactylum tricornutum

A multi-step aqueous and non-aqueous extraction procedure was applied to recovery bio-molecules from Phaeodactylum tricornutum. The process include that physical pre-treatments (high voltage electrical discharges (HVED, 40 kV/cm, 1–8 ms, HVED samples) or high pressure homogenization (HPH, 1200 bar, 10 passes, P samples)) (1st step); aqueous extraction (2nd step); pigments extraction in ethanol (3rd step); and lipids extraction in CHCl3/MeOH (4th step). The extractability of ionics, carbohydrates, proteins, pigments and lipids for untreated, HVED and P samples were evaluated. The results evidenced that HVED allowed selective extraction of water soluble ionic products at 1st and 2nd steps. The maximum ionic concentrations were found for HVED samples. However, P samples resulted in higher contents of extracted components as compared to HVED samples (≈1.5-fold of carbohydrates, ≈2.5-fold of proteins, ≈5-fold of carotenoids, and ≈3-fold of chlorophylls). Moreover, the non-aqueous extraction (3rd and 4th steps) allowed supplementary extraction of pigments and lipids. Industrial relevancePre-treatments by high voltage electrical discharge (HVED) or high pressure homogenization (HPH) allowed effective extraction of different bio-molecules from microalga biomass. The combination of HVED/HPH, aqueous and non-aqueous extraction allowed selective recovery of target molecules. The paper also presents a multistage extraction procedure allowed reducing the amount of toxic solvents, increasing the extraction efficiency, and reducing the energy consumption. These approaches opened the doors to high-efficiency recovery of valuable compounds from microalgae relevant for industrial application.

Challenges in developing polymer flocculants to improve bitumen quality in non-aqueous extraction processes: an experimental study

Western Canada’s oil sands hold the third-largest hydrocarbon deposits in the world. Bitumen, a very heavy petroleum, is currently recovered by surface mining with warm water or in situ. Recovery processes that use organic solvents are being developed to reduce water usage and tailings production. While solvent-based methods can effectively extract bitumen, removal of residual fine solids from diluted bitumen product (DBP) to meet the pipeline transport requirement of < 0.5 wt% solids and water in DBP remains a major challenge. We propose a novel area of application of polymer flocculants for fine solids removal from DBP. In principle, polymer flocculants can be applied to help remove these residual solids in conjunction with physical separation processes to increase process effectiveness and energy efficiency. Several polymers are selected and screened for flocculation behavior using kaolinite suspended in DBP and toluene, as a model system. Focused beam reflectance measurements and force tensiometer techniques are used to determine flocculation and sedimentation in DBP. The observed flocculation and sedimentation rate enhancements indicate that the polymers tested have only minor effects, providing opportunities for advanced polymer development. These findings exemplify the challenges in identifying polymers that may be effective as flocculants in heavy petroleum media.

Understanding the stabilization mechanism of bitumen-coated fine solids in organic media from non-aqueous extraction of oil sands

Considerable amounts of fine solids retained in the bitumen product have been a challenging issue impeding the industrial application of the non-aqueous extraction (NAE) of oil sands ore. The undesired stable suspension of bitumen-coated fine solids in the bitumen-solvent mixture is generally considered as the origin of solid migration to the NAE bitumen. In this work, two advanced nanomechanical techniques, i.e., colloidal probe atomic force microscope (AFM) and quartz crystal microbalance with dissipation (QCM-D), were utilized to unravel the stabilization mechanism of fine silica solids in organic solvents, including cyclohexane, heptane and the mixed solvents. The adsorbed bitumen layer on the silica surfaces exhibited a swelling behavior in cyclohexane-rich solvent, giving rise to strong repulsion between the fine silica solids. Addition of heptane to the organic media could notably weaken the inter-particle repulsion by causing the shrink and collapse of bitumen layer. The degree of adsorption of bitumen layer on the silica surfaces could be significantly enhanced by slightly decreasing volume fraction of cyclohexane (φc) in the mixed solvents but could be inversely inhibited as φc was smaller than the asphaltene precipitation onset. The stability of bitumen-coated silica solids in organic solvent was also examined via sedimentation tests. It was found that the settling efficiency could be markedly enhanced by decreasing φc in surrounding solvent. Our results provide useful insights into the stabilization mechanism of fine solids in NAE bitumen, with important implications for developing effective and economical strategies of removing fine solids from the NAE bitumen product.

Solvent-Kaolinite Interactions Investigated using the 3D-Rism-Kh Molecular Theory of Solvation

AbstractThe oil sands of western Canada represent the third largest hydrocarbon deposit in the world. Bitumen, a very heavy petroleum, is recovered from mined oil sands using warm water extraction followed by separation treatments to isolate the bitumen product. The high energy, water use, as well as tailings remediation challenges associated with the warm water extraction process raise major environmental concerns. Non-aqueous extraction using organic solvents at room temperature has been investigated extensively as an alternative to the warm water extraction process. The main challenge to the large-scale implementation of non-aqueous extraction is the retention of solvent in the tailings. The objective of this work was to present and validate a computational model for the interaction of solvents used in non-aqueous extraction with minerals, such as the abundant and adsorbent clay mineral kaolinite. The model system contained a periodically extended kaolinite platelet immersed in a solvent and all were treated at the atomic level using the 3D Reference Interaction Site Model with the Kovalenko-Hirata closure approximation (3D-RISM-KH) molecular theory of solvation. The solvent solvation free energy of interaction with kaolinite as well as site-specific adsorption energies and kinetic barriers for desorption were computed based on the solvent site density distribution functions. Moreover, the lateral and integrated density distributions were computed to analyze the organization of solvent at kaolinite surfaces. The integrated density distribution profiles were correlated with experimental adsorption isotherms. The results showed very strong adsorption of ethanol and weak adsorption of hydrocarbon solvents on kaolinite, which were in qualitative agreement with experimental solvent extraction reports. The model and these findings are valuable in understanding the mechanism of solvent retention in tailings after non-aqueous extraction and highlight the action of hydroxylated cosolvent additives to enhance extraction using nonpolar solvents.

Computational and Experimental Investigations of the Role of Water and Alcohols in the Desorption of Heterocyclic Aromatic Compounds from Kaolinite in Toluene

Nonaqueous extraction is an attractive alternative to the currently employed warm water process for extraction of bitumen from oil sands, as it could use less energy and water. Hydroxylated cosolvents, such as alcohols, that compete for the adsorptive clay surfaces and help release bitumen components could help improve bitumen recovery. The water naturally present in oil sand also affects oil–mineral interactions. Electronic structure methods and the statistical-mechanical 3D-RISM-KH molecular theory of solvation as well as experimental desorption measurements are employed to study the effects of water and aliphatic alcohol cosolvents in toluene solvent on the desorption of fused pyridinic heterocycles (ArN) from kaolinite. The geometries of phenanthridine and acridine (representative of pyridinic heterocycles of petroleum asphaltenes) adsorbed on the kaolinite clay surface are optimized in periodic boundary conditions using density functional theory. The 3D-RISM-KH method is employed to calculate the solvation free energy and potential of mean force for adsorption of the heterocycles on kaolinite in pure and alcohol-containing toluene. The potentials of mean force show that the adsorption of the fused pyridines on kaolinite is stronger in pure toluene than in toluene mixed with aliphatic alcohol. Analysis of the mechanism of desorption of phenanthridine and acridine from kaolinite in toluene containing alcohol reveals that the alcohol stabilizes both the pyridinic moiety and kaolinite platelet by hydrogen bonding, thus disrupting the ArN···HO–Al(kaolinite) hydrogen bond. A mechanism for retention of toluene on kaolinite is also highlighted. Experimental studies of the desorption of fused pyridines from an ArN–kaolinite aggregate show that in water-saturated toluene the rate of desorption of the phenanthridine from kaolinite is twice as high as that in dry toluene. The experimental and computational results show that water and aliphatic alcohols in toluene help desorb pyridinic heterocycles from kaolinite, a clay mineral abundant in the oil sands. The presented insights are valuable for understanding the molecule-clay interactions in solution and relevant to improving the nonaqueous extraction of bitumen from oil sand.

Effective Interactions and Adsorption of Heterocyclic Aromatic Hydrocarbons in Kaolinite Organic Solutions Studied by 3D-RISM-KH Molecular Theory of Solvation

We employ the molecular theory of solvation also known as the three-dimensional reference interaction site model with the Kovalenko–Hirata closure relation (3D-RISM-KH) to study adsorption of several heterocyclic aromatic hydrocarbons (acridine, benzothiophene, carbazole, dibenzothiophene, indole, and phenanthridine), which are intended to represent bitumen fragments on the surfaces of a single-sheet kaolinite nanoparticle in cyclohexane and toluene solvents. In addition to adsorption, we also examine solvent-mediated effective interactions between two kaolinite nanoparticles in organic and aqueous solutions. The proposed adsorption model serves as a simple prototype of suspensions formed during nonaqueous extraction of bitumen from oil sands of the Athabasca Basin. Using the proposed computational approach, excess adsorption isotherms of bitumen fragments on two different faces of kaolinite were calculated and compared in cyclohexane and toluene solvents at several temperatures. Almost all the studied molecules show strong preference for adsorption on the octahedral aluminum hydroxide surface of kaolinite. While adsorption of the molecules on the tetrahedral silicon oxide surface is weaker, it is still significant compared to the octahedral surface and for some of the studied molecules adsorption appears to be stronger than for the octahedral surface. Due to the better surface and bulk solvation properties of toluene, the adsorption of the bitumen fragments in toluene is weaker than in cyclohexane. Potentials of mean force between kaolinite nanoplatelets in cyclohexane at several temperatures were calculated using the 3D-RISM-KH molecular theory of solvation. Evaluation of effective interactions by conventional molecular simulation techniques generally requires costly free energy integration and therefore is usually avoided by adopting simple and often unrealistic semiempirical effective potentials. On the other hand, the 3D-RISM-KH molecular theory of solvation offers a fully atomistic description with all-atom force fields and notable performance advantages over molecular simulations. Obtained in this way potentials of mean force in organic solvents exhibit complex oscillating behavior and generally possess deeper main minima and smaller aggregation barriers than the corresponding potentials in aqueous solution.

Recent Advances in Nonaqueous Extraction of Bitumen from Mineable Oil Sands: A Review

Investigations of nonaqueous extraction (NAE) of bitumen from minable oil sands have been extensively revisited in the past decade as an alternative to Clark hot water extraction (CHWE). Significant advances have been achieved in understanding NAE processes at bench and pilot scales, although many questions remain regarding the commercialization of NAE. This critical review summarizes recent research findings and progress on fundamental and practical aspects associated with novel extraction processes, focusing on the technological method, solvent selection, recovery of solvent, and removal of fines. The review also identifies opportunities and challenges for bitumen recovery from oil sands using nonaqueous processes.

Novel Determination of Organic Acids in Diesel and Motor Oil by Ion Chromatography

ABSTRACTA robust analytical method is required for the determination of low-molecular weight organic acids, which are potential causes of refinery and internal combustion engine corrosion. The ion chromatographic method developed in this study allows the determination of acetic acid and formic acid in diesel oil mixtures with a motor oil volume fraction of up to 10%. The hydrophobic matrix is automatically removed in-line through a matrix elution step with organic solvent and nonaqueous anion-exchange analyte extraction. Acetic acid and formic acid, as the smallest and most acidic aliphatic naphthenic acids, were determined. Gradient anion-exchange chromatography on high-capacity columns in combination with suppressed conductivity detection allowed their selective and sensitive determination. Typical recovery values were from 82 to 107% for each acid in the matrices evaluated with reproducibility less than 5% for acid fortified samples.

Efficient Procedure for N-Glycan Analyses and Detection of EndoH-Like Activity in Human Tumor Specimens.

Although the importance of glycosylation has been thoroughly recognized in association with a number of biological processes, efficient assessments of glycans have been hampered by both the limited size of specimens and lengthy sample preparations, particularly in clinical settings. Here we report a simple preparative method for N-glycan analyses. It involves only short one-step chloroform-methanol extraction in presence or absence of water prior to PNGase F deglycosylation. The procedure was successfully applied to the investigation of N-glycans obtained from small numbers of in vitro cultured cancer cells (≤1 × 10(5)) and to tumor tissues, including patient biopsies of small size. MALDI-MS analysis confirmed the efficient release of all N-glycan types including complex forms with poly-N-acetyllactosamine chains. In addition, nonaqueous extraction of specimens from several established cancer cell lines, as well as patient tumor tissues, yielded high-mannose glycans with one GlcNAc moiety (Man3-9GlcNAc), strongly suggesting preservation of enzymatic activity analogous to Endo H enzyme. In summary, the method is both a step toward the practical use of glycan profiling and a way to detect Endo H-like activity in cancer specimens.