Analysis Of Polar Compounds Research Articles

An adhesive hydrogel functionalized silica sphere for polar analytes separation and analysis

In response to the challenges associated with the chromatographic separation of polar compounds, this study aims to devise a solution by introducing a novel stationary phase. Hydrogels, characterized by a three-dimensional network structure, have aroused wide attention owing to its functional designability, multiple interaction sites and good adhesion, etc. In this work, an adhesive hydrogel functionalized silica stationary phase (Sil@PVA/TA) was synthesized using physical coating technique. Due to the co-existence of hydroxyl and benzene ring in the hydrogel structure, the obtained composites materials exhibited excellent separation performance for various of compounds and excellent column efficiency up to 71385.6 plates/m for thymidine. Furthermore, the hydrogel functionalized silica demonstrated superior selectivity to bare silica, diol-column and NH2-column for the separation of various of polar molecules, including, nucleosides/bases, alkaloids, organic acids, antibiotics and amino acids. Notably, for alkaloids, which frequently encounter peak tailing issues, Sil@PVA/TA demonstrated superior peak shape compared with C18 column. In short, this study successfully synthesized a hydrogel functionalized silica stationary phase, offering a novel method for the separation and analysis of polar compounds.

Liquid electron ionization-mass spectrometry as a novel strategy for integrating normal-phase liquid chromatography with low and high-resolution mass spectrometry.

Normal-phase liquid chromatography (NPLC) plays a pivotal role in the rapid separation of non-polar compounds, facilitating isomer separation and finding applications in various crucial areas where aprotic solvents are necessary. Similar to reversed-phase liquid chromatography (RPLC), NPLC requires a robust and sensitive detector to unequivocally identify the analytes, such as a mass spectrometer. However, coupling NPLC with mass spectrometry (MS) poses challenges due to the incompatibility between the non-polar solvents used as the mobile phase and the primary ionization techniques employed in MS. Several analytical methods have been developed to combine NPLC with electrospray ionization (ESI), but these methods are restricted to the analysis of polar compounds. In most cases, atmospheric pressure chemical ionization (APCI) becomes necessary to expand the range of analysis applications. To overcome these limitations and fully realize the potential of NPLC-MS coupling, a technique termed liquid electron ionization-mass spectrometry (LEI-MS) can be used. LEI-MS offers a straightforward solution by enabling the effective coupling of NPLC with both low and high-resolution MS. LEI allows for the comprehensive analysis of non-polar compounds and provides a powerful tool for isomer separation and precise identification of analytes. Optimal separations, mass spectral qualities, and matches with the NIST library were obtained in both configurations, demonstrating the potential of the proposed approach.

ESI FT-ICR MS Analysis of Polar Compounds in Natural Bitumen of Munaily-Mola Oil Sands and Its Asphaltenes

ESI FT-ICR MS Analysis of Polar Compounds in Natural Bitumen of Munaily-Mola Oil Sands and Its Asphaltenes

Automated sequential solid-phase microextraction to address displacement effects in the quantitative analysis of polar compounds

Automated sequential solid-phase microextraction to address displacement effects in the quantitative analysis of polar compounds

Particulate matter pollution and non-targeted analysis of polar compounds in three regions of Brazil

Atmospheric Particulate Matter (PM) is a pollutant with diverse origins, exhibiting varying chemical compositions, and undergoes several molecular transformations in the atmosphere. In this study, PM samples (PM2.5, PM10 and TSP) were collected in five Brazilian cities (Camboriú-SC; Catalão-GO; Florianópolis-SC; Limeira-SP and Novo Hamburgo-RS) during the four seasons of the year. Analysis of Variance (ANOVA) was used to evaluate the differences between each city and season in PM concentration. PM10 average concentrations were higher in the city of Limeira, compared to the other (ANOVA p-values and Tukey's test). Moreover, Tukey's test demonstrated differences between the average PM10 concentrations in summer and winter. Regarding TSP and PM2.5, Tukey's test showed differences between winter and warm seasons (spring and summer). Moreover, polar compounds from the samples collected in the summer (February) and winter (August) periods were analyzed (Ultra-High-Performance Liquid Chromatography coupled to a Quadrupole Time-of-Flight Mass Spectrometer) following a non-targeted approach and annotated. This is the first study to carry out this type of analysis in these five Brazilian cities. Despite the differences in PM concentrations, profiles of polar organic compounds, showed similarities between samples/and, in general, the same compounds were present, albeit with different intensities. The annotated compounds are associated with vehicle emissions and plastics, which are considered important global air polluters. Therefore, there is an urgent necessity for comprehensive studies aimed at investigating the non-targeted compounds existing in the atmosphere. Such research can provide invaluable insights to policymakers, enabling them to formulate effective guidelines and policies to mitigate particulate matter concentration and enhance overall air quality.

Development of an analytical method for the simultaneous determination of 50 semi-volatile organic contaminants in wastewaters

This work describes the development of a robust analytical methodology for the simultaneous determination of 50 semi-volatile organic compounds (SVOCs) in wastewater effluent samples by solid-phase extraction (SPE) followed by gas chromatography coupled to mass spectrometry (GC–MS) analysis. In this work, we studied extensively whether the validated SPE method used for the analysis of polar compounds in wastewaters could be extended to the analysis of non-polar compounds in the same analytical run. To that aim, the effect of different organic solvents in the SPE process (i.e., sample conditioning prior to SPE, elution solvent and evaporation steps) was evaluated. In this sense, the addition of methanol to wastewater samples before the extraction, the use of hexane:toluene (4:1, v/v) mixture for the quantitative elution of target compounds, and the addition of isooctane during the evaporation were required to minimize analyte losses during SPE and enhance extraction yields. Overall, the developed methodology showed a good performance for the determination of 50 SVOCs, and was further applied to the analysis of real wastewater effluent samples.•A validated SPE method for polar compounds was extended to the analysis of non-polar compounds.•Elution with hex:tol (4:1, v/v) and the addition of isooctane during the evaporation yield good recoveries.•The developed methodology was suitable for the determination of 50 SVOCs in aqueous samples.

Exploration of the effects of chloride ions on the analysis of polar compounds at low concentrations by hydrophilic interaction liquid chromatography coupled to a charged aerosol detector: Application to tromethamine.

In this study, we discuss the origin of the slightly increased response of the charged aerosol detector when low-concentration polar drugs formulated with sodium chloride are analyzed by hydrophilic interaction liquid chromatography coupled to the charged aerosol detector. In the case of tromethamine mixed with saline solutions, we investigated several levels including the mobile phase, sample matrix, and detection. We show that the analysis of the rich-salted sample results in both interactions with the mobile phase modifiers and the stationary phase during the run time. With 150mM NaCl as a compounding solution, a slight increase in the tromethamine peak area was observed(<5.5%). Our study suggests that chloride ions in excess sequentially interact firstly with the counterions from the organic modifiers and secondly with the analyte via the stationary phase and the contribution of hydrophilic interaction liquid chromatography retention mechanisms. Because of these effects, the hydrophilic interaction liquid chromatography-charged aerosol detector analysis of drugs in saline solutions requires particular attention, and a correction factor for quantitative purposes that accounts for formulation ions remains appropriate.

Biomarkers Profile of the Mysterious 2019 Oil Spill on the Northeast Coast of Brazil and Discrimination from Unreported Events

In 2019, large amounts of oil reached the northeast coast of Brazil, causing damage to the environment and the local economy, especially in the state of Pernambuco. In order to correlate with possible sources, investigation was made of the geochemical biomarkers of the oils using “gold standard” forensic protocols from the European Committee for Standardization (CEN). The biomarkers study was improved by using gas chromatography-tandem mass spectrometry (GC-MS/MS), rather than the standard protocol that suggests use of the selected ion monitoring (SIM) method. Analysis was made of thirteen oil samples from the Pernambuco coast, in order to identify their degrees of similarity and the possible presence of oils from unreported spills. The use of eighteen diagnostic ratios and multivariate analysis revealed a cluster formed by eleven samples with biomarker distributions typical of oil from the 2019 spill. However, two samples had anomalous fingerprints, especially due to the absence of the 18α(H)-oleanane and 18β(H)-oleanane isomers. Both the CEN protocol applied for the classical biomarkers and a comprehensive Fourier transform mass spectrometry (FT-MS) analysis of polar compounds confirmed the dissimilarities between the samples. The findings suggested that these two oils could have originated from an event unrelated to the mysterious 2019 spill.

Application of heart-cutting two-dimensional liquid chromatography-mass spectrometry to the characterization of highly polar impurities in calcium gluconate injection

The separation and characterization of small polar impurities in polar drugs such as calcium gluconate products are always challenging, due to their poor retention on traditional reversed phase (RP) columns. Although ion-pair reversed-phase liquid chromatography (IPRP-LC) and hydrophilic interaction liquid chromatography (HILIC) are commonly used methods for polar compound analysis, both methods have some drawbacks. For example, IPRP-LC is incompatible with mass spectrometry (MS) due to the presence of non-volatile salts in its mobile phase and HILIC has limited sensitivity due to the poor solubility of polar drugs in the organic-rich sample diluents used in HILIC separations. In order to characterize the highly polar impurities in calcium gluconate injections, a heart-cutting two-dimensional liquid chromatography (2D-LC) method coupled with quadrupole time-of-flight mass spectrometry (Q-TOF/MS) was developed in this study. An IPRP-LC method in the first dimension (1D) provided the selectivity for the separation of polar analytes, using a 100% aqueous mobile phase containing phosphate buffer and ion-pair reagent. Heart cuts of target peaks were collected with sample loops and transferred to the second dimension (2D) HILIC column using an organic-rich mobile phase. In order to solve the mobile phase mismatch problem between the two dimensions, a make-up flow module was introduced in the 2D-LC system to dilute the 1D-water-rich fractions with acetonitrile before entering the sample loops. By optimizing the loop size and dilution factor, good retention and peak shape of the highly polar impurities were obtained on the 2D-HILIC column, and the ion suppression effect for MS detection from the ion-pair reagent and non-volatile salt in the 1D-effluent was minimized. A total of five impurities were identified through fragmentation studies by Q-TOF/MS analysis and their fragmentation pathways were proposed. Four of them were further confirmed by reference substances. This study not only provided useful information for quality control of calcium gluconate injections, but also provided an alternative method for polar impurity characterization in pharmaceuticals.

A novel and versatile Hybrid HILIC and Ion Exchange Phase for the LC/MS Analysis of Polar Compounds

LebensmittelchemieVolume 76, Issue S2 p. S2-140-S2-140 Analytik (ATW-A) A novel and versatile Hybrid HILIC and Ion Exchange Phase for the LC/MS Analysis of Polar Compounds S.H. Liang, S.H. Liang Restek Corporation, 110 Benner Circle, Bellefonte, PA, 16823 United StatesSearch for more papers by this authorC. Flannery, C. FlannerySearch for more papers by this authorD. Li, D. LiSearch for more papers by this author S.H. Liang, S.H. Liang Restek Corporation, 110 Benner Circle, Bellefonte, PA, 16823 United StatesSearch for more papers by this authorC. Flannery, C. FlannerySearch for more papers by this authorD. Li, D. LiSearch for more papers by this author First published: 01 September 2022 https://doi.org/10.1002/lemi.202259097AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume76, IssueS2September 2022Pages S2-140-S2-140 RelatedInformation

The Characteristics and Analysis of Polar Compounds in Deep-Frying Oil: a Mini Review

The Characteristics and Analysis of Polar Compounds in Deep-Frying Oil: a Mini Review

Hydrophilic Interaction Liquid Chromatography (HILIC): Latest Applications in the Pharmaceutical Researches

Background: Significant advances have been occurred in analytical research since the 1970s by Liquid Chromatography (LC) as the separation method. Reverse Phase Liquid Chromatography (RPLC) method, using hydrophobic stationary phases and polar mobile phases, is the most commonly used chromatographic method. However, it is difficult to analyze some polar compounds with this method. Another separation method is the Normal Phase Liquid Chromatography (NPLC), which involves polar stationary phases with organic eluents. NPLC presents low-efficiency separations and asymmetric chromatographic peak shapes when analyzing polar compounds. Hydrophilic Interaction Liquid Chromatography (HILIC) is an interesting and promising alternative method for the analysis of polar compounds. HILIC is defined as a separation method that combines stationary phases used in the NPLC method and mobile phases used in the RPLC method. HILIC can be successfully applied to all types of liquid chromatographic separations such as pharmaceutical compounds, small molecules, metabolites, drugs of abuse, carbohydrates, toxins, oligosaccharides, peptides, amino acids and proteins. Objective: This paper provides a general overview of the recent application of HILIC in the pharmaceutical research in the different sample matrices such as pharmaceutical dosage form, plasma, serum, environmental samples, animal origin samples, plant origin samples, etc. Also, this review focuses on the most recent and selected papers in the drug research from 2009 to the submission date in 2020, dealing with the analysis of different components using HILIC. Results and Conclusion: The literature survey showed that HILIC applications are increasing every year in pharmaceutical research. It was found that HILIC allows simultaneous analysis of many compounds using different detectors.

Nuclear Magnetic Resonance Aerosolomics: A Tool for Analysis of Polar Compounds in Atmospheric Aerosols.

Nuclear magnetic resonance aerosolomics was proposed as a new approach to the analysis of the water-soluble organic compound fraction in aerosol particulate matter. The identification of individual compounds is based on a comparison of precise chemical shifts in the 1H NMR spectrum with the signals in the standards library. For this purpose, Chenomx metabolomics software and a comprehensive spectra library of 150 compounds known from chemistry of aerosols were used. This approach enabled the identification of 60 compounds in real aerosol samples collected at a suburban site in Prague. Using the metabolomic spectra library, three new compounds were identified in aerosols for the first time, and an association of four other compounds to the atmospheric particulate matter was confirmed. The obtained concentration profiles of all identified chemical individuals were subsequently subjected to advanced statistical analysis. NMR aerosolomics clearly differentiates between summer and winter aerosol samples via multivariate statistical analysis and revealed some interesting trends in composition, according to aerosol particle size. Furthermore, the univariate statistical analysis was applied to highlight compounds responsible for the group separation, and possible sources of these compounds were suggested.

Study on the effects and changes of soil degradation under the influence of antibiotics

The use of antibiotics in large quantities against the combat of pests in soils, indicates an increased remanence of them, which leads to major environmental risks. After entering in the soil, antibiotics are subjected to a succession of biogeochemical processes under the action of multiple environmental factors: absorption, migration, transformation, degradation or nutritional prosperity of plants. In order to know the current state of the environment and the effects of antibiotics it is essential to discover procedures for improving the degradation and combating the dissemination of antibiotic resistance. Research in recent years on the extraction of antibiotics from the soil is based on complex processes, such as: Soxhlet extraction, ultrasonic extraction or accelerated solvent extraction. Soil residue was determined using liquid chromatography coupled with mass spectrometry, being the equipment that provides the highest accuracy in the analysis of polar compounds in very low concentrations. The purpose of the paper is to find an efficient and ecological solution for the elimination of antibiotics from soils and to highlight the evaluation of the contaminated land regarding the antibiotic residues and the impact on the composition of the bacterial community. Information about the effects of antibiotics accumulated in soil, persistence, resistance and sensitivity to chemical and microbiological substances, degradation and results related to soil fertility and crop production are highlighted.

COPMONENT COMPOSITION OF ROOT IN TWO SPECIES OPLOPANAX (ARALIACEAE)

The qualitative and quantitative composition of two species of Oplopanax root was studied by gas chromatography with mass spectrometric detection. Extraction of components from the investigated objects was carried out by extraction of dry ground raw material with 70% ethanol. For the analysis of polar compounds, the extracts were further derivatized to give the corresponding trimethylsilyl derivatives. Identification of components was carried out using commercial (NIST17, Wiley14) and own custom mass-spectrometer libraries. The percentage of components found was calculated using the areas of the corresponding chromatographic peaks. Found in these samples were 130 compounds of various classes: terpenes and their derivatives, alcohols, aldehydes, polyyns, polyenes, various acids and their derivatives, phenols, sterols, lignans, vitamins, nucleosides, glycosides and sugars. It has been established that the qualitative and quantitative composition of root extracts varies even within the same species. The presence of 26 compounds common to the two species of Oplopanax, including 12 acids, 3 polyyns, 6 terpenes and one representative each from the class polyenes, aldehydes, lignans, glycosides and sterols, was revealed. As a result of the comparative analysis, it was established that 4 compounds from the class of polyyns (falcarindiol acetate, oplopanediol acetate, oplopantriol A and oplopantriol B) are found only in the roots of O. horridus.

Effect of Conventional Water Pretreatment Devices on Polar Compound Analysis

In general, water vapor in the sample gas can cause adverse effect on analytical instruments. Therefore, the removal of water vapor from the sample gas is a pivotal issue when analyzing polar compounds. The effects of water pretreatment devices on polar compound analysis were investigated in this study. Nafion dryer and Cooler, which are the most widely used water pretreatment device in the world, were compared. Three types of Nafion dryers and two types of Coolers were used. The main target polar compounds were methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), isobutyl alcohol(i-BuAl) and butyl acetate(BuAc) which are designated as odorous compounds in Korea. In order to investigate the effect of the water pretreatment device on target compounds, the water vapor removal test and the recovery test were conducted. When the water vapor removal test was performed with 50% and 90% of RH, Nafion dryers(65.4%-96.6%) showed higher water removal efficiencies than those of Coolers (34.2%–67.2%). During a recovery test, Nafion dryers revealed lower recovery rate and lower reproducibility than Coolers. In particular, Nafion dryers showed very low recovery rate and low reproducibility with respect to MEK and i-BuAl which had high water solubility. It was found that Nafion dryers were not suitable for polar compounds of concern. In addition, Coolers had limitation in water vapor removal as well. Therefore, further research on water pretreatment devices that can overcome the problems is necessary.

Preparation and evaluation of hydrophobically associating polyacrylamide coated silica composite as high performance liquid chromatographic stationary phase

A hydrophobically associating polyacrylamide (HAPM)-coated silica packing (HAPM@silica) as a novel stationary phase was synthesized by a simple thermal immobilization to separate multiple polar compounds for the first time. The successful immobilization of HAPM on the silica support was confirmed by elemental analysis, scanning electron microscopy (SEM) and the Brunauer–Emmett–Teller (BET). The thickness of HAPM coating is crucial and the one-layer HAPM@silica stationary phase was demonstrated the highest separation efficiency. Compared with the bare silica and amino modified silica, the new stationary phase showed better separation performance for multiple polar compounds such as bases, alkaloids, carbohydrates and amino acid compounds under the experimental conditions. The chromatographic behaviors were evaluated by investigating the effects of acetonitrile content, water content, mobile phase pH on separation. A typical hydrophilic interaction liquid chromatography (HILIC) retention feature of HAPM based column was observed at the low percentage of water content. The packing material also showed excellent chromatographic repeatability with intraday RSDs of the retention time of five bases less than 0.46% (n = 10) and interday RSDs less than 1.45% (n = 5). In summary, the new chromatographic material can be used for a feasible option for analysis of polar compounds.

The Performance Investigation of Bimodal Cation Exchange/Hydrophilic Interaction Liquid Chromatography–Electrospray Ionization Mass Spectrometry by Modifying Mobile Phase Composition in Amino Acid Separation

Owing to its unique selectivity, mixed‐mode chromatography (MMC) has been extended to the analysis of biological fluids. Among various MMC applications, ion exchange/hydrophilic interaction liquid chromatography (IEX/HILIC) is particularly beneficial for the analysis of polar compounds without derivatization or ion pairing. Nevertheless, no practical information about the retention behavior is discussed. In this study, the chromatographic behavior of amino acids in a CEX/hydrophilic interaction mixed‐mode column via the modification of the mobile phase was investigated. A low buffer salt concentration led to increased retention; particularly, positively charged amino acids were not eluted by excessive interactions with the negatively charged stationary phase at a moderate salt concentration (&lt;20 mM). An acid modifier of formic acid or acetic acid exhibited a similar effect on the separation, and a low acid concentration (&lt;0.5%) led to peak broadening by additional ion exchange with a silanol group at high pH. With respect to the composition of organic solvents, aprotic solvents such as tetrahydrofuran or acetonitrile afforded appropriate retention. However, protic solvents led to the considerably reduced retention except positively charged amino acids. Novel, practical information for the optimization or development of applications with a CEX/HILIC column for polar analytes such as amino acids was obtained.

Multi-Spheres Adsorptive Microextraction (MSAμE)-Application of a Novel Analytical Approach for Monitoring Chemical Anthropogenic Markers in Environmental Water Matrices.

Multi-spheres adsorptive microextraction using powdered activated carbons (ACs) was studied as a novel enrichment approach, followed by liquid desorption and high-performance liquid chromatography with diode array detection (MSAµE(AC)-LD/HPLC-DAD) to monitor caffeine (CAF) and acetaminophen (ACF) traces in environmental matrices. In this study, commercial activated carbons (N, NOX, and R) were tested, with the latter showing a much better performance for the analysis of both anthropogenic drugs. The main parameters affecting the efficiency of the proposed methodology are fully discussed using commercial AC(R). Textural and surface chemistry properties of the ACs sample were correlated with the analytical results. Assays performed on 30 mL of water samples spiked at 10 µg L−1 under optimized experimental conditions, yielding recoveries of 75.3% for ACF and 82.6% for CAF. The methodology also showed excellent linear dynamic ranges for both drugs with determination coefficients higher than 0.9976, limits of detection and quantification of 0.8–1.2 µg L−1 and 2.8–4.0 µg L−1, respectively, and suitable precision (RSD < 13.8%). By using the standard addition method, the application of the present method to environmental matrices, including superficial, sea, and wastewater samples, allowed very good performance at the trace level. The proposed methodology proved to be a feasible alternative for polar compound analysis, showing to be easy to implement, reliable, and sensitive, with the possibility to reuse and store the analytical devices loaded with the target compounds for later analysis.

Development and application of a HILIC UHPLC-MS method for polar fecal metabolome profiling

The fecal metabolome is a complex mixture of endogenous, microbial metabolites, and food derived compounds. Hydrophilic interaction liquid chromatography (HILIC) enables the analysis of polar compounds, which is a valuable alternative to reversed-phase liquid chromatography in the field of metabolomics due to its ability to retain a greater portion of the polar metabolome. The objective of the study was to find the optimal chromatographic solution to perform non-targeted metabolomics of feces by means of HILIC ultra-high-pressure liquid chromatography mass spectrometry (UHPLC-Q-TOF-MS). The performance was systematically investigated analyzing a pooled fecal sample, and mixtures of 150 metabolites from different families, including for example amino acids, amines, indole derivatives, fatty acids and carbohydrates. Three different stationary phases (zwitterionic, amide and unbonded silica) were operated at three pH values (4.6, 6.8 and 9.0), and three salt gradient conditions (5–5, 5–10 and 5–25 mM ammonium acetate). Amide and zwitterionic stationary phases performed similarly at low pH, with highest number of detected standards, which increased by increasing the salt gradient. The amide column showed slightly better performance in terms of separation of isomers and peak widths and remarkably good performance at basic pH, with highest number of metabolite features in the non-targeted analysis. The zwitterionic column operated best in terms of number of detected standards, retention time distribution of standards and metabolite feature across whole chromatographic run. Thus, the zwitterionic column was proven to suit for non-targeted analysis of fecal samples, resulting in good coverage of especially amino acids and carbohydrates.