Combination Of Capillary Electrophoresis Research Articles

Laconic Review on Capillary Electrophoresis-Mass Spectrometry in Separation of Proteins

Abstract: The separation technique known as electrophoresis is made possible by the ability of liquid molecules to travel through an electric field. Early in the 1980s, it was discovered that considerable separation efficiencies could be obtained by passing a voltage across a capillary. In the late 1980s and early 1990s, commercial capillary electrophoresis (CE) first became accessible. Mass spectrometry is a powerful tool for identifying unknowns, studying molecular structure, and investigating the fundamental principles of chemistry. The most efficient technique combines high-resolution separations by CE with high-sensitivity and selectivity detections by MS, which is typical for bioanalytical applications and targets or thoroughly high throughput studies of low-concentration analytes frequently occurring in complicated matrices. The combination of capillary electrophoresis with mass spectrometry, or CE-MS, has emerged as an effective standard technique for the analysis of a wide variety of analytes. CEMS, a proteomic technology that combines chromatographic techniques with MS to increase the resolving power, is a well-liked technique for proteome analysis.

A study of azopyrimidine photoswitches and their interactions with cyclodextrins: When the guest governs the type of accommodation at the host

Azopyrimidines have recently emerged as a new class of photoswitches structurally similar to azobenzenes switching between trans and cis isomers. These compounds have a wide range of potential applications in photopharmacology, catalysis or as molecular devices, but their low solubility in water limits their biological applications. Nevertheless, this drawback could be overcome by their inclusion into supramolecular structures. To test this hypothesis, we prepared a series of azopyrimidines and investigated their structure, cis-trans isomerization and host-guest chemistry with cyclodextrins (CDs) using an experimental-theoretical approach combining capillary electrophoresis (CE), Nuclear Magnetic Resonance (NMR) spectroscopy and computational models. The results revealed that β-CD exhibits high selectivity over several CDs tested for the accommodation of the studied compounds. Orientation of guests in inclusion complexes was experimentally assessed by Nuclear Overhauser Effect (NOE) contacts and supported by quantum-chemical calculations. Moreover, investigation of noncovalent interactions of azopyrimidines with β-CD by CE showed that azopyrimidines with suitable structural modification can form strong complexes with high values of binding constants (over 17 000 L mol−1). For such complexes, trans-cis isomerization proceeds directly inside the β-CD cavity with azopyrimidine remaining encapsulated through its narrower primary portal. By contrast, in weakly interacting complexes, the trans isomer is released, and the cis isomer is generated outside the cavity. In subsequent re-complexation, the cis isomer is then re-captured through the wider secondary portal. Therefore, our findings point to two significantly different complexation processes depending on substitutional pattern and binding constant values of azopyrimidines; a feature which may lead to future promising applications.

Simultaneous Determination of Nicotine and Phenolic Compounds in Tobacco by Capillary Electrophoresis with Pipette Tip Electrodes

Aim: The aim of this work is to fabricate pipette tip electrodes for the capillary electrophoretic determination of nicotine and phenolic compounds in tobacco. Background: The content of nicotine affects not only the quality of tobacco products but also the health of smokers. Phenolic compounds are important flavor precursors in tobacco. The quantity of phenolic compounds is one of the most important evaluation indicators of tobacco quality. It is of high importance to determine nicotine and phenolic compounds in tobacco for quality control and the health of smokers. Objective: A method based on capillary electrophoresis and amperometric detection was developed for the simultaneous determination of nicotine, rutin, chlorogenic acid, quercetin, ferulic acid, gallic acid, and protocatechuic acid in tobacco leaves. Pipette electrodes were designed and fabricated for their amperometric detection. Method: Nicotine, rutin, chlorogenic acid, quercetin, ferulic acid, gallic acid, and protocatechuic acid were determined by capillary electrophoresis in combination with the detection electrodes that were fabricated by packing the composite of carbon nanotube and epoxy in pipette tips. Results: Detection potentials, the acidity and concentrations of background electrolyte, separation voltages, and injection times were optimized. At a high voltage of 12 kV, separation of the seven analytes could be achieved in less than 11 min in a piece of 40 cm long fused silica capillary with a background electrolyte of 50 mM borate buffer (9.2). Linearity was observed between the peak currents and the concentrations, with the limits of detection ranging from 0.1 to 0.2 μM for the seven analytes at the pipette electrodes. The method was applied in the simultaneous determination of nicotine and phenolic compounds with satisfactory assay results. Conclusions: The pipette tip electrodes were successfully coupled with capillary electrophoresis for tobacco analysis. The CE-AD method provides not only a simple approach for the quality control of tobacco and its preparations but also an alternative technique for the constituent and fingerprint investigation of other plants.

N-Glycan Isomer Differentiation by Zero Flow Capillary Electrophoresis Coupled to Mass Spectrometry.

Isomeric N-glycans often vastly differ in their biological activities, hence the need for methods that allow resolving and structurally characterizing them in biological material. Here, we established a zero flow approach using capillary electrophoresis in combination with (tandem) mass spectrometry to allow structural characterization of isomeric N-glycans at high sensitivity. Additionally, diagnostic fragment ion ratios were identified, indicative for the antenna carrying specifically linked sialic acids. In total, 208 N-glycans were characterized in human plasma, with 57 compositions showing multiple isomers.

Development of On-Site Rapid Detection Device for Soil Macronutrients Based on Capillary Electrophoresis and Capacitively Coupled Contactless Conductivity Detection (C4D) Method

The acquisition of nutrient data on a precise scale has played a vital role in nutrient management processes for soils. However, the lack of rapid precise and multi-index detection techniques for soil macronutrient contents hinders both rational fertilization and cost reduction. In this paper, a rapid detection method and device were devised, combining capillary electrophoresis (CE) and capacitively coupled contactless conductivity detection (C4D), and presented to detect macronutrient contents of soil. The device consisted of a capillary channel, C4D detector, high-voltage system, etc. It separated macronutrient ions using capillary electrophoresis and then measured the ion concentration based on the C4D principle. Lime concretion black soil samples from a complete field were collected and detected. NO3−, NH4+, H2PO4− and K+ in sample solutions could be detected in 5 min with relative standard deviations (RSDs) from 1.0 to 7.51%. The injection voltage was set to 10 kV for 5 s, and the separation voltage was set to 14 kV. This demonstrated the excellent performance of the C4D device on the detection of soil macronutrients, which could help to guide fertilization operations more effectively.

Analysis of protein phosphorylation combining capillary electrophoresis with ATP analog labeling technique.

Protein phosphorylation is one of the most basic mechanisms for regulating and controlling protein biological activity and function, and it is also a very important posttranslational modification process. Protein phosphorylation participates in and regulates many life activities such as signal transduction, gene expression, cell cycle, and so on. In this paper, we propose a method for the determination of the protein phosphorylation combining capillary electrophoresis (CE) with ATP analog labeling technique. We synthesized two new ATP analogs (ATP-NB and ATP-TATD-NB) functionalized by norbornene. Using Abl kinase as a model, we established a method for the determination of the kinase activity in solution and lysate by CE with laser-induced fluorescence detection (CE-LIF). This method was used to evaluate the efficiencies of kinase inhibitors. The IC50 values obtained are basically consistent with the reports. By D-A reaction (inverse electron demand Diels-Alder reaction) to label TZ-BODIPY fluorescence, we also realized the phosphorylation fluorescence detection of substrate peptide. Then, we used fluorescence confocal microscopy imaging technology to study the phosphorylation of proteins in vivo by the D-A reaction of ATP-NB and TZ-BODIPY. Our preliminary results documented that the combination of CE-LIF with analog ATP-NB labeling technique is an effective strategy for the determination of the protein phosphorylation and the kinase activity and for screening of kinase inhibitors. The D-A reaction of ATP-NB and TZ-BODIPY also laid the foundation for the subsequent in situ study of protein phosphorylation.

Biosynthesis of UDP-2-acetamido-4-formamido-2,4,6-trideoxy-hexose by WekG, WekE, WekF, and WekD: Enzymes in the Wek pathway responsible for O-antigen Assembly in Escherichia coli O119

Considering the importance of bacterial glycoconjugates on virulence and host mimicry, there is a need to better understand the biosynthetic pathways of these unusual sugars to identify critical targets involved in bacterial pathogenesis. In this report, we describe the cloning, overexpression, purification, and biochemical characterization of the four central enzymes in the biosynthesis pathway for UDP-2-acetamido-4-formamido-2,4,6-trideoxy-hexose, WekG, WekE, WekF, and WekD. Product peaks from enzyme-substrate reactions were detected by using a combination of capillary electrophoresis (CE) and electrospray ionization-mass spectrometry (ESI-MS). Putative enzyme assignments were provided by protein sequence analysis. Combined with the mass spectrometric characterization of pathway intermediates, we propose a biosynthetic pathway for UDP-2-acetamido-4-formamido-2,4,6-trideoxy-hexose. This process involves C-4, C-6 dehydration, C-4 amination, and formylation. CID-ESI-MSn result confirmed that the final product is a 4 formamido derivative too rather than the 3 formamido derivatives as reported earlier.

Single-Round DNA Aptamer Selection by Combined Use of Capillary Electrophoresis and Next Generation Sequencing: An Aptaomics Approach for Identifying Unique Functional Protein-Binding DNA Aptamers.

In DNA aptamer selection, existing methods do not discriminate aptamer sequences based on their binding affinity and function and the reproducibility of the selection is often poor, even for the selection of well-known aptamers like those that bind the commonly used model protein thrombin. In the present study, a novel single-round selection method (SR-CE selection) was developed by combining capillary electrophoresis (CE) with next generation sequencing. Using SR-CE selection, a successful semi-quantitative and semi-comprehensive aptamer selection for thrombin was demonstrated with high reproducibility for the first time. Selection rules based on dissociation equilibria and kinetics were devised to obtain families of analogous sequences. Selected sequences of the same family were shown to bind thrombin with high affinity. Furthermore, data acquired from SR-CE selection was mined by creating sub-libraries that were categorized by the functionality of the aptamers (e. g., pre-organized aptamers versus structure-induced aptamers). Using this approach, a novel fluorescent molecular recognition sensor for thrombin with nanomolar detection limits was discovered. Thus, in this proof-of-concept report, we have demonstrated the potential of a "DNA Aptaomics" approach to systematically design functional aptamers as well as to obtain high affinity aptamers.

Far Infrared-assisted Sample Extraction and Solvent Removal for Capillary Electrophoretic Determination of the Bioactive Constituents in Citri Reticulatae Pericarpium

Background: Sample preparation is crucially important for the capillary electrophoretic measurement of the bioactive constituents in Citri Reticulatae Pericarpium because conventional solvent extraction is time-consuming and the solvent peaks seriously interfere with the measured capillary electropherograms. Objective: The objective of the present study is to establish far infrared-assisted sample preparation approaches for the analysis of Citri Reticulatae Pericarpium. Methods: Synephrine and hesperidin in Citri Reticulatae Pericarpium were determined by capillary electrophoresis in combination with far infrared-assisted sample extraction and solvent removal. Results: The effects of detection potentials, irradiation times and the voltages applied to the infrared generator were investigated to acquire the optimal assay conditions. Synephrine and hesperidin could be well separated within 6 min at a separation voltage of 9 kV in an alkaline borate solution. Satisfactory linearity was observed over the concentration range of 0.001 to 1 mM with the detection limits of 0.43 and 0.52 μM for synephrine and hesperidin, respectively. The results exhibited that far infrared irradiations could enhance the efficiencies of sample extraction and solvent removal during the sample preparation of Citri Reticulatae Pericarpium. The extraction time was significantly reduced to 6 min while the interference of the solvent peaks towards the electropherograms was eliminated. Conclusion: Far infrared-accelerated extraction and solvent removal were employed in the capillary electrophoretic determination of the bioactive constituents in Citri Reticulatae Pericarpium with satisfactory results. The ease, simplicity, efficiency and low cost of the novel sample preparation approaches indicate they may find a wide range of applications.

Selenium speciation in watermelon by g-C3N4 enrichment combined with capillary electrophoresis-inductively coupled plasma-mass spectrometry

Selenium is one of the essential trace elements in the human body, and it plays a critical role in human health. In this work, 2.0 g melamine was placed in an alumina crucible, which was heated in a box-type resistance furnace for 2 h at 600 ℃, at the heating rate of 3 ℃/min, and then cooled to room temperature. After cooling, yellow graphite phase carbon nitride (g-C3N4) nanosheets were obtained. Subsequently, 500 mg of the nanosheets was dispersed in 50 mL water with ultrasonication for 10 h in order to remove the residual un-exfoliated g-C3N4 nanoparticles and large-sized nanosheets. The obtained suspension was centrifuged at about 10000 r/min, followed by drying at 60 ℃ to produce g-C3N4. The prepared g-C3N4 was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), and field emission-environmental scanning electron microscopy (SEM) analyses. Given that the selenium content in actual samples is very low, high sensitivity, and accuracy are imperative for selenium detection. The combination of capillary electrophoresis (CE) with inductively coupled plasma-mass spectrometry (ICP-MS) can greatly improve the sensitivity, accuracy, and speed of the analysis. A novel method based on CE-ICP-MS was established for the determination of selenourea (SeUr), L-selenocystine (SeCys2), DL-selenomethionine (SeMet), selenite (Se(Ⅳ)), selenate (Se(Ⅵ)), and selenoethionine (SeEt) in watermelon. The selenium species in watermelon were extracted by ultrasonication with pepsin as an extractant and g-C3N4 enrichment. The enrichment factor of g-C3N4 ranged from 12 to 29. Six selenium species were completely separated within 11 min in a 100-cm-long capillary with 100 μm internal diameter, at an applied voltage of 22 kV, using a buffer solution of 8 mmol/L NaH2PO4-12 mmol/L H3BO3-0.2 mmol/L cetyl trimethyl ammonium bromide (CTAB; pH 9.2). The interference in the selenium detection was eliminated using a dynamic reaction cell with CH4. The linear correlation coefficients of all the selenium species were greater than 0.9995. Under the optimal conditions, the limits of detection (3 σ, σ for standard deviation, as Se) for SeUr, SeCys2, SeMet, Se(Ⅳ), Se(Ⅵ), and SeEt were 6.2, 30, 11, 8.2, 48, and 5.5 ng/L, respectively. The linear range (as Se) for SeUr, SeCys2, SeMet, Se(Ⅳ), Se(Ⅵ), and SeEt were 0.017-20 μg/L, 0.091-50 μg/L, 0.032-40 μg/L, 0.023-60 μg/L, 0.015-75 μg/L, and 0.015-30 μg/L, respectively. The recoveries ranged from 96.0% to 106%, and the relative standard deviations (RSDs; n=5) were less than 3%. The developed method is simple, rapid, and sensitive, and it is also suitable for the detection of selenium species in other food and environmental samples.

Joint forces of direct, single particle, CE- and HPLC-inductively coupled plasma mass spectrometry techniques for the examination of gold nanoparticle accumulation, distribution and changes inside human cells.

The intracellular localization and transformation of gold nanoparticles (AuNPs) are among the crucial aspects in future applications in cancer therapy. In the context of the study, inductively coupled plasma mass spectrometry (ICP-MS)-based techniques were effectively applied to reveal the fate of AuNPs internalized in cancerous MCF-7 cells. Direct ICP-MS was used to obtain quantitative information about the distribution rate of gold from the AuNPs in the cells, namely their membranes, cytosol as well as nuclei. Moreover, the combination of capillary electrophoresis and reversed-phase liquid chromatography with ICP-MS was used as a tool to probe and compare for the effective monitoring of the speciation changes of the gold-containing forms in the cytosol. The chemical nature (ionic vs. nano) of the metal detected in the cytosol was verified via ICP-MS in a single-particle mode, confirming the stability of the nanomaterials and the absence of ionic gold forms inside the cells.

How Corona Formation Impacts Nanomaterials as Drug Carriers.

As drugs/drug carriers, upon encountering physiological fluids, nanoparticles adsorb biological molecules almost immediately to form a biocorona, which is often simply called a corona. Once the corona is formed, it dictates the subsequent fate of the drug nanoparticle as a therapeutic agent. Protein adsorption on micron-size or even bigger particles was originally described by the Vroman effect. It has served as a useful framework to understand the corona formation. Proteins that are irreversibly adsorbed on nanoparticles form what is called a hard corona. Beyond that is the exchangeable population of proteins, which constitute the dynamic structure called a soft corona. More than the abundance, the affinity of the proteins toward the nanoparticles decides which ones end up in the corona. For example, the more common serum albumin, which is deposited initially, is displaced by fibrinogen, which has a higher affinity for gold nanoparticles. The curvature of the particle is a crucial parameter with bigger particles generally able to bind a more diverse population of proteins from the physiological milieu. The earlier perception of the corona formation being a challenge for drug targeting, etc. has been turned into an opportunity by engineering corona to manipulate properties like circulating half-lives, capacity to evade the immune system, and targeting or even overcoming the blood-brain barrier. The most commonly used techniques for particle characterization, including dynamic light scattering (DLS), differential sedimentation centrifugation, transmission electron microscopy (TEM), and SDS-PAGE, have been adopted to study corona formation in the past. Many newer tools, for example, a combination of capillary electrophoresis with mass spectrometry, are being used to study the corona composition. The comparison of interlaboratory results is a problem because of the lack of standard protocols. This has hindered the ability to obtain more precise information about the corona composition. That, in turn, affects our prospects to use nanoparticles as drugs/drug carriers. This overview is an attempt to assess our understanding of corona formation critically and to outline the complexities involved in gaining precise information. The discussion is largely focused on findings of the last year or so.

Online Concentration of Bacteria from Tens of Microliter Sample Volumes in Roughened Fused Silica Capillary with Subsequent Analysis by Capillary Electrophoresis and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry.

This study presents a timely, reliable, and sensitive method for identification of pathogenic bacteria in clinical samples based on a combination of capillary electrophoresis with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. In this respect, a part of a single-piece fused silica capillary was etched with supercritical water with the aim of using it for static or dynamic cell-surface adhesion from tens of microliter sample volumes. The conditions for this procedure were optimized. Adhered cells of Staphylococcus aureus (methicillin-susceptible or methicillin-resistant) and of Pseudomonas aeruginosa were desorbed and preconcentrated from the rough part of the capillary surface using transient isotachophoretic stacking from a high conductivity model matrix. The charged cells were swep and separated again in micellar electrokinetic chromatography using a nonionogenic surfactant. Static adhesion of the cells onto the roughened part of the capillary is certainly volumetric limited. Dynamic adhesion allows the concentration of bacteria from 100 μL volumes of physiological saline solution, bovine serum, or human blood with the limits of detection at 1.8 × 102, 1.7 × 103, and 1.0 × 103 cells mL-1, respectively. The limits of detection were the same for all three examined bacterial strains. The recovery of the method was about 83% and it was independent of the sample matrix. A combination of capillary electrophoresis with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry required at least 4 × 103 cells mL-1 to obtain reliable results. The calibration plots were linear (R2 = 0.99) and the relative standard deviations of the peak area were at most 2.2%. The adhered bacteria, either individual or in a mixture, were online analyzed by micellar electrokinetic chromatography and then collected from the capillary and off-line analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry without interfering matrix components.

Determination of oxaliplatin enantiomers at attomolar levels by capillary electrophoresis connected with inductively coupled plasma mass spectrometry

The aim of this study was to develop a method for the separation of oxaliplatin enantiomers at attomolar concentration levels. A combination of capillary electrophoresis and inductively coupled plasma mass spectrometry was chosen due to their unique characteristics, including fast and easy modification of separation selectivity, and significant limits of detection and linearity. In the first step, we optimized conditions for the separation of oxaliplatin enantiomers including background electrolyte composition and concentration, pH, and type and concentration of the chiral selector. Under optimal conditions, sodium borate buffer pH 9.5, ionic strength 40 mmol L−1, with 60 mg mL−1 sulfated β-cyclodextrin, separation was obtained with a resolution of 2.0. This electrolyte system was then used in the ‘in-house’ connection of capillary electrophoresis with inductively coupled plasma mass spectrometer. In this instance, separation lasted for 9.5 min. Calibrations were linear in the range of 0.1–500 μg mL−1 with R2 of 0.9999. LOD and LOQ values were of 64 ng mL−1 and 116 ng mL−1 of oxaliplatin, respectively. This represents detection of 49 fg or 125 attomol of oxaliplatin enantiomers in the capillary electrophoresis injected sample zone. Finally, the method was successfully applied for detection of oxaliplatin enantiomers in spiked urine samples.

Combination of capillary electrophoresis and molecular modeling to study the enantiomer affinity pattern between β-blockers and anionic cyclodextrin derivatives in a methanolic and water background electrolyte.

In order to have deep insights into the mechanisms of enantiomer affinity pattern in both aqueous and non-aqueous systems, an approach combining capillary electrophoresis and molecular modeling was undertaken. A chiral β-blocker; acebutolol, was enantioseparated in aqueous capillary electrophoresis and non-aqueous capillary electrophoresis using two anionic β-cyclodextrin derivatives. The enantiomer affinity pattern of acebutolol was found to be opposite when an aqueous background electrolyte was replaced with non-aqueous background electrolyte in the presence of heptakis(2,3-di-O-acetyl-6-sulfo)-β-cyclodextrin but remained the same in the presence of heptakis(2,3-di-O-methyl-6-sulfo)-β-cyclodextrin. Molecular docking of acebutolol into two β-cyclodextrin derivatives indicated two distinct binding modes called 'up' and 'down' conformations. After structure optimization by molecular dynamics and energy minimization, both enantiomers of acebutolol were preferred to the 'up' conformation with heptakis(2,3-di-O-methyl-6-sulfo)-β-cyclodextrin while 'down' conformation with heptakis(2,3-di-O-acetyl-6-sulfo)-β-cyclodextrin. The further calculation of the complex energy with solvent effect indicated that heptakis(2,3-di-O-acetyl-6-sulfo)-β-cyclodextrin had higher affinity to S-acebutolol than R-acebutolol in non-aqueous capillary electrophoresis while it showed better binding to R-acebutolol in aqueous capillary electrophoresis. However, the heptakis(2,3-di-O-methyl-6-sulfo)-β-cyclodextrin bound better to R-acebutolol in both aqueous and non-aqueous capillary electrophoresis, implying that the binding mode played more important role in chiral separation of heptakis(2,3-di-O-methyl-6-sulfo)-β-cyclodextrin while the solvent effect had prevailing impact on heptakis(2,3-di-O-acetyl-6-sulfo)-β-cyclodextrin.

Simultaneous detection of three foodborne pathogenic bacteria in food samples by microchip capillary electrophoresis in combination with polymerase chain reaction

A rapid and sensitive PCR based strategy in combination with microchip capillary electrophoresis (MCE) was employed to simultaneously detect three foodborne pathogenic bacteria. Three pairs of primers were specially designed for the amplification of target genes from Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Salmonella enterica serovar Typhimurium (S. Typhimurium). The PCR products along with standard DNA fragments were employed to optimize the separation conditions in MCE. Under optimal conditions, detectable separation of the PCR products (1.6–3.5 ng μL−1) from the three foodborne pathogenic bacteria was achieved within 135 s. The limits of detection of the three bacteria were concluded to be as low as 45 CFU mL−1 for E. coli, 62 CFU mL−1 for S. aureus and 42 CFU mL−1 for S. Typhimurium. The RSD of migration time was in the range of 0.5–0.8%. We conclude that MCE along with PCR holds real potential for rapid analysis and detection of nucleic acids from routine foodborne pathogenic bacteria.

Determination of tetracyclines in human urine samples by capillary electrophoresis in combination with field amplified sample injection.

A sensitive method using CZE-UV detection has been developed for the determination of five tetracycline antibiotics in human urine samples. To improve the sensitivity of the method, an on-line preconcentration strategy, named field-amplified sample injection, has been developed, based on the electrokinetic injection of the sample, which requires only a 1:100 dilution with sample solvent before injection. Under optimum conditions, sensitivity enhancement factors ranged from 450 to 800 for the studied compounds. The applicability of the proposed method was demonstrated by the determination of these antibiotics in spiked urine samples. The limits of quantification were lower than 0.8mg/L and the precision (intra- and inter-day), expressed as %RSD was below 14%. Recoveries ranged from 92.1 to 96.7%. Thus, the proposed procedure is a simple, fast and efficient strategy which could be used as therapeutic drug monitoring in human urine samples.

Chemometric approach integrated with capillary electrophoresis for the investigation of public water system sources and quality

A chemometric approach coupled with capillary electrophoresis based on the hierarchical cluster analysis and principal component analysis has been applied for the investigation of the water quality in the Golcuk-Isparta region (Lake District of Turkey). In the research area, Egirdir Lake, Golcuk Lake and surrounding ground and domestic waters have been utilized as drinking water resources. Golcuk Lake is distinctive in terms of high fluoride content (3.50 ± 0.21 mg/mL) which is endemic in volcanic areas where the water flow through volcanic rocks and sediments. Based on the analysis of major anions chloride, sulfate, nitrate and fluoride with capillary electrophoresis, twenty-four drinking water sampling sites in the research area were classified into four classes using the hierarchical cluster and principal component analysis. Combining the research area investigation results of hierarchical cluster and principal component analysis, it was found that fluoride concentration is the major diagnostic variable to determine the quality of drinking waters, and all the other anions are the important classification factors to predict the resources of the drinking water samples, individually. To sum up, this study reveals the potential of the use of capillary electrophoresis in combination with chemometric techniques for the determination of the quality and origin of drinking waters.

Europium (III) and Uranium (VI) complexation by natural organic matter (NOM): Effect of source.

For the safe long-term storage of high-level radioactive waste (HLW), detailed information about geo-chemical behavior of radioactive and toxic metal ions under environmental conditions is important. Natural organic matter (NOM) can play a crucial role in the immobilization or mobilization of these metal ions due to its complexation and colloid formation tendency. In this study, the complexation of europium (as chemical homologue of trivalent actinides such as americium) and uranium (as main component of HLW) by ten humic acids (HA) from different sources and Suwannee NOM river extract has been analyzed. Capillary electrophoresis in combination with inductively coupled plasma mass spectrometry has been used for the evaluation of complex stability constants logβ. In order to determine the complex stability constants a conservative single site model was used in this study. In dependence of their source and thus of NOM structure the log β values for the analyzed humic acids are in the range of 6.1-7.0for Eu(III) and 5.2-6.4 for U(VI) (UO22+ ), respectively. In contrast to the results for HA the used Suwannee river NOM reveals logβ values in the range of nearly two orders of magnitude lower (4.6 for Eu3+ and 4.5 for UO22+ ) under the geochemical conditions applied in this study.

The potential of SNP-based PCR-RFLP capillary electrophoresis analysis to authenticate and detect admixtures of Mediterranean olive oils.

Authentication and traceability of extra virgin olive oil is a challenging research task due to the complexity of fraudulent practices. In this context, the monovarietal olive oils of Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI) require new tests and cutting edge analytical technologies to detect mislabeling and misleading origin. Toward this direction, DNA-based technologies could serve as a complementary to the analytical techniques assay. Single nucleotide polymorphisms are ideal molecular markers since they require short PCR analytical targets which are a prerequisite for forensic applications in olive oil sector. In the present study, a small number of polymorphic SNPs were used with an SNP-based PCR-RFLP capillary electrophoresis platform to discriminate six out of 13 monovarietal olive oils of Mediterranean origin from three different countries, Greece, Tunisia, and Lebanon. Moreover, the high sensitivity of capillary electrophoresis in combination with the DNA extraction protocol lowered the limit of detection to 10% in an admixture of Tsounati in a Koroneiki olive oil matrix.