Journal of chromatography open最新文献

{"title":"Quantitative screening of organophosphorus and organochlorine pesticides in water and soil using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry","authors":"Kuan Wang,&nbsp;Fengshou Dong,&nbsp;Xinglu Pan,&nbsp;Xiaohu Wu,&nbsp;Jun Xu,&nbsp;Yongquan Zheng","doi":"10.1016/j.jcoa.2024.100140","DOIUrl":"10.1016/j.jcoa.2024.100140","url":null,"abstract":"<div><p>Organophosphorus and organochlorine pesticides, historically or currently widely used in agriculture, are prevalent in the environment and pose significant risks to public health and ecosystems. This study aimed to develop a robust analytical method for quantifying these pesticides in soil and water. By optimizing solid-phase extraction (SPE) and Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) procedures, and utilizing comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOF-MS), we achieved sensitive detection levels of all organophosphorus and organochlorine pesticides at 10 μg/kg for soil and 0.1 μg/kg for water samples. The mean recoveries were in the range of 74.2–118.3 % and 72.3–106.9 % at fortified concentration levels in soil and water, respectively. The method exhibited good linearity (R² ≥ 0.9874) and precision (relative standard deviations from 0.1 % to 29.9 %), providing a reliable approach for environmental monitoring and advancing the capabilities in pesticide residue analysis.</p></div>","PeriodicalId":93576,"journal":{"name":"Journal of chromatography open","volume":"5 ","pages":"Article 100140"},"PeriodicalIF":0.0,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772391724000276/pdfft?md5=37e53fb4e54d7b346c3a9d58d790860d&pid=1-s2.0-S2772391724000276-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141044345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Selective solid phase extraction of phototoxic furanocoumarins using molecularly imprinted polymers","authors":"Rebecca Hofer,&nbsp;Tobias Schlappack,&nbsp;Christian W. Huck,&nbsp;Matthias Rainer","doi":"10.1016/j.jcoa.2024.100133","DOIUrl":"10.1016/j.jcoa.2024.100133","url":null,"abstract":"<div><p>Furanocoumarins are secondary plant metabolites found in citrus plants. Essential oils from these plants are widely used in cosmetic products. They have attracted attention for their phototoxicity, which can even lead to skin burns. Therefore, the furanocoumarin concentration is controlled by the European Union according to Regulation (EC) No. 1223/2009, where a limit of 1 mg kg⁻¹ is specified in sun protection and bronzing agents. This study describes the synthesis of two molecularly imprinted polymers (methacrylamide and methacrylic acid as monomers) as novel materials for solid phase extraction. After optimisation of the extraction protocol, both polymers gave satisfying recovery results for a furanocoumarin standard mixture containing the six markers proposed by the International Fragrance Association (IFRA). Furthermore, spiked sun oil samples were extracted using an adapted extraction protocol. Since the studies showed promising results including 75–149 % recovery and 100 % loading efficiency for the methacrylic acid polymer, a validation of the analytical method was performed. Analysis was performed using HPLC-MS/MS in high specificity multi-reaction monitoring mode. The validation showed acceptable results for most parameters. In addition, a comparison with commercially available Strata-X cartridges was completed, revealing superior recovery performance of the molecularly imprinted polymer. In conclusion, molecularly imprinted polymers represent a novel and efficient method for selective solid-phase extraction of phototoxic furanocoumarins.</p></div>","PeriodicalId":93576,"journal":{"name":"Journal of chromatography open","volume":"5 ","pages":"Article 100133"},"PeriodicalIF":0.0,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772391724000203/pdfft?md5=c4a91275e6b1567648ac47d2be20acd9&pid=1-s2.0-S2772391724000203-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140777535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integration of ultrashort-chain compounds into the biomonitoring of per- and polyfluorinated substances in human plasma and serum","authors":"Shun-Hsin Liang,&nbsp;Justin A. Steimling","doi":"10.1016/j.jcoa.2024.100132","DOIUrl":"https://doi.org/10.1016/j.jcoa.2024.100132","url":null,"abstract":"<div><p>Ultrashort-chain (USC) per- and polyfluoroalkyl substances (PFAS) are small and very polar compounds with carbon chain lengths of shorter than C4. Their ubiquitous and high levels of occurrence in environmental aquatic systems have raised significant concern in conjunction with long-chain PFAS contamination. Measuring USC PFAS in blood can not only monitor human exposure but also serves as a valuable tool for studying the potential risks associated with USC PFAS exposure. The high polarity of USC PFAS poses a challenge to current analytical practices based on the reversed-phase liquid chromatography, primarily due to insufficient chromatographic retention. In this study, a simple and reliable workflow was developed for the simultaneous analysis of C1 to C10 perfluoroalkyl carboxylic and sulfonic acids, along with four alternative PFAS, in human plasma and serum. The chromatographic analysis was conducted using a polar-embedded reversed-phase LC column. Fetal bovine serum (FBS) was chosen for method validation due to its absence of all analytes, except for trifluoroacetic acid (TFA). Subsequently, a TFA isotope, ¹³C-TFA, was employed as a surrogate to assess the method accuracy for TFA in FBS. A single-step sample preparation procedure, conducted by mixing 100 µL of FBS with 200 µL of methanol, was demonstrated to be effective for the accurate and precise analysis of fortified FBS samples. Ten isotopes of C3 to C10 PFAS, serving as extracted internal standards, were added to the samples at 1 ppb to validate the accuracy of the entire workflow. Calibration standards were prepared in reverse osmosis water due to its cleanliness for all analytes. Phosphate-buffered saline was incorporated into the calibration standard solution to achieve similar chromatographic performance between standard and sample solutions. The calibration ranges varied among different analytes, spanning from 0.05 – 40 ppb, 0.1 – 40 ppb, 0.25 – 40 ppb, and 0.5 – 40 ppb. Method accuracy and precision were evaluated at three fortification levels, ranging from 0.4 to 30 ppb. All analytes and extracted internal standards exhibited recovery values within 20 % of the nominal concentration across all fortification levels. Satisfactory method precision was demonstrated with%RSD values &lt;12 %. The validated method was applied to measure PFAS in NIST 1950 and 1957 standard reference human plasma and serum, affirming the established workflow is suitable for accurate quantification of C1 to C10 PFAS in human plasma and serum matrices.</p></div>","PeriodicalId":93576,"journal":{"name":"Journal of chromatography open","volume":"5 ","pages":"Article 100132"},"PeriodicalIF":0.0,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772391724000197/pdfft?md5=022e9db720b719c8cbb2105cfa822410&pid=1-s2.0-S2772391724000197-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140638645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advanced sample preparation and chromatographic techniques for analyzing plant-based bioactive chemicals in nutraceuticals","authors":"M. Mesud Hurkul ,&nbsp;Ahmet Cetinkaya ,&nbsp;Seyda Yayla ,&nbsp;Sibel A. Ozkan","doi":"10.1016/j.jcoa.2024.100131","DOIUrl":"https://doi.org/10.1016/j.jcoa.2024.100131","url":null,"abstract":"<div><p>Since ancient times, humanity has used plants to cure diseases or maintain health. Nowadays, obtaining the bioactive components of plants and researching their effects continues at great speed. Plant-derived chemicals are studied with great interest in the food, pharmaceutical and cosmetic industries. The complexity of city life limits access to plants in their natural habitat. Nutraceuticals are indispensable products of our age to protect health. Many methods have been developed and successfully applied for extracting crude plant extracts and pure active substances included in nutraceuticals from plant tissues and their quantitative analysis. This study compiled the methods for obtaining plant extracts and active ingredients and the techniques developed for analyzing bioactive compounds. The extraction methods of plant-based bioactive chemicals (maceration, soxhlet extraction, decoction, infusion, hydro distillation, ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), enzyme-assisted extraction (EAE), pressurized liquid extraction (PLE), and supercritical fluid extraction (SFE)) were explained in detail, and some important plant-based bioactive chemicals and source plants were summarized in table form. Additionally, the studies using different analytical techniques such as high-performance liquid chromatography (HPLC), gas chromatography (GC), thin layer chromatography (TLC), mass spectrometry (MS), and ultra-performance liquid chromatography (UPLC) were discussed. Finally, evaluating its effectiveness in the extraction of different bioactive compounds and the prospects for more environmentally friendly methods alternative to traditional solvents were emphasized. This review covers the latest practices and new trends in analyzing plant-based bioactive chemicals in nutraceuticals over the last three years.</p></div>","PeriodicalId":93576,"journal":{"name":"Journal of chromatography open","volume":"5 ","pages":"Article 100131"},"PeriodicalIF":0.0,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772391724000185/pdfft?md5=8457932e92afe8de32ed5582eaccdd56&pid=1-s2.0-S2772391724000185-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140645097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Supercritical fluid chromatographic chiral separation of potential P2RX7 antagonists containing one, two and three chiral centers","authors":"Naomi KNAVS ,&nbsp;Andreea ZUBAŞ ,&nbsp;Georgiana APOSTOL ,&nbsp;Christophe FURMAN ,&nbsp;Adrian Sorin NICA ,&nbsp;Bezhan CHANKVETADZE ,&nbsp;Alina GHINET ,&nbsp;Emmanuelle LIPKA","doi":"10.1016/j.jcoa.2024.100129","DOIUrl":"https://doi.org/10.1016/j.jcoa.2024.100129","url":null,"abstract":"<div><p>Eleven polysaccharide-based chiral stationary phases were screened to separate stereoisomers of six lactam derivatives by supercritical fluid chromatography (SFC). Those molecules are antagonists of the P2×7 receptor with potential anti-inflammatory activity. They present a mixture of either two enantiomers, or four or eight stereoisomers depending on the number of chiral centers in their structure. The effect of chiral stationary phase, either amylose- or cellulose-based, coated or immobilized, chlorinated or non-chlorinated, on retention and selectivity of those compounds was studied. The effect of the co-solvent nature (methanol, ethanol, propan-2-ol and acetonitrile) and percentage (15 to 40 %), temperature (20 to 45 °C) and backpressure (8 to 20 MPa) on the enantioseparation and retention of 1-(2-chlorobenzyl)-5-((4-methoxyphenyl)amino)pyrrolidin-2-one (compound <strong>4</strong>) was thoroughly studied. Thus, optimal conditions were defined for each derivative in order to implement the preparative separation of the whole series, except of 1-((3,4-dimethoxyphenyl)(phenyl)methyl)-5-oxo-<em>N</em>-(1-phenylethyl)pyrrolidine-2-carboxamide) (compound <strong>6</strong>) for which none of the eleven columns could resolve the eight stereoisomers. The small-scale preparative separation of the enantiomers of the most promising derivative, <em>i.e.</em> 3-acetyl-1-(4-chlorophenyl)-<em>N</em>-(2,4-dichlorobenzyl)-5-oxopyrrolidine-2-carboxamide (compound <strong>2</strong>), is presented.</p></div>","PeriodicalId":93576,"journal":{"name":"Journal of chromatography open","volume":"5 ","pages":"Article 100129"},"PeriodicalIF":0.0,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772391724000161/pdfft?md5=eec5c3bd35747f6479636b04172ecfa7&pid=1-s2.0-S2772391724000161-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140555009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The unveiling of a levulinic acid isomer in high performance liquid chromatography analysis, a key point for the reliable determination of the catalytic conversion of levulinic acid to γ-valerolactone","authors":"Zaira Ruiz-Bernal ,&nbsp;Elena Georgiana Tane ,&nbsp;Nuria Burgos-Bolufer ,&nbsp;M. Ángeles Lillo-Ródenas ,&nbsp;M. Carmen Román-Martínez","doi":"10.1016/j.jcoa.2024.100128","DOIUrl":"https://doi.org/10.1016/j.jcoa.2024.100128","url":null,"abstract":"<div><p>This work was motivated by the difficulties found in the analysis and quantification of levulinic acid (LA) and the reaction products resulting from the catalyzed transformation of LA into γ-valerolactone (GVL) using High Performance Liquid Chromatography (HPLC). The starting study carried out with the Zorbax Eclipse XDB-C8 column and UV/Vis detector (or Diode Array Detector, DAD) was puzzling, mainly because two different signals appeared in the analysis of aqueous LA standards. The use of C8-UV/Vis-MS and the measurements with DAD in range wavelength mode (RWL) allowed to suggest the presence of pseudo-LA (sometimes regarded as unidentified impurities in the reactant) together with LA. The finding of an additional LA species was fundamental for the accurate quantification of LA, necessary to provide reliable results in the analysis of the catalytic LA transformation products. The study carried out also allowed the identification of 4-hydroxypentanoic acid (HPA), a labile intermediate compound. The analysis of the target solution (resulting from the explained catalytic system) was also performed with a REZEX ROA-Organic Acid H⁺ column and Refractive Index Detector (RID) in order to determine its applicability and to check if the results obtained with the two configurations were coherent. The REZEX-RID configuration led to a simpler analysis, as it did not involve the separation of the LA species, and allowed the detection of 1,4-pentanediol (not possible by UV/Vis analysis). The results obtained with REZEX-RID helped to support the need of considering the presence and quantification of an LA isomer in the standard solutions for the right quantification of LA using the C8-UV/vis (or DAD) configuration. The present study clarifies relevant practical aspects of the HPLC-UV/Vis (or DAD) analysis of LA present in aqueous solutions.</p></div>","PeriodicalId":93576,"journal":{"name":"Journal of chromatography open","volume":"5 ","pages":"Article 100128"},"PeriodicalIF":0.0,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S277239172400015X/pdfft?md5=5fb956b5930e2439d8e0124b6e5dac78&pid=1-s2.0-S277239172400015X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140536477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distribution of Vicine, Convicine and Levodopa in Faba Bean Plant Tissues Determined by UltraHigh Performance Liquid Chromatography-Electrospray Ionization Mass Spectrometry","authors":"Devini De Silva ,&nbsp;Yong Liu ,&nbsp;Mark A Smith ,&nbsp;Albert Vandenberg ,&nbsp;Haixia Zhang","doi":"10.1016/j.jcoa.2024.100127","DOIUrl":"https://doi.org/10.1016/j.jcoa.2024.100127","url":null,"abstract":"<div><p>Faba bean is an emerging pulse crop for the Canada Prairies and is becoming an increasingly important source of plant sourced protein. It also has a high content of levodopa (up to 0.1 % of the dry seed weight), a nutraceutical compound for treating Parkinson's Disease (PD). The presence of pyrimidine glycosides, vicine and convicine, however, restricts the use of faba due to their potential to cause favism in susceptible individuals. For the rapid separation and quantification of levodopa, vicine and convicine, a 5-min ultrahigh performance liquid chromatography-electrospray ionization mass spectrometry method (UHPLC-ESI MS) was developed. This method provided a wide linear range of quantification (4.8 nM to 60 µM for vicine, and 6.0 nM to 24 µM for convicine and levodopa), and low limit of detection (1.2 to 3.0 nM). The method was applied in the analysis of diverse faba bean samples, from dehulled mature faba bean and seed coat, to fresh plant tissues such as flowers, leaves, stems, roots and pods. The results indicated that fresh faba bean plant tissues, such as leaves and flowers, had the highest concentration of levodopa and low level of VC, which makes them an alternative source of plant-based <span>l</span>-DOPA with potential as a food-based treatment for Parkinson's Disease.</p></div>","PeriodicalId":93576,"journal":{"name":"Journal of chromatography open","volume":"5 ","pages":"Article 100127"},"PeriodicalIF":0.0,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772391724000148/pdfft?md5=2858a0d425d23d9d4ea3f8b82fa8cf03&pid=1-s2.0-S2772391724000148-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140163322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the performance of cellulose tris-3,5-dichlorophenylcarbamate as a stationary phase for the chiral electro-chromatographic separation of azole antifungals","authors":"Massimo Giuseppe De Cesaris ,&nbsp;Giovanni D'Orazio ,&nbsp;Chiara Fanali ,&nbsp;Alessandra Gentili ,&nbsp;Salvatore Fanali","doi":"10.1016/j.jcoa.2024.100126","DOIUrl":"https://doi.org/10.1016/j.jcoa.2024.100126","url":null,"abstract":"<div><p>In this study, the enantiorecognition and separation performance of cellulose tris-3,5-dichlorophenylcarbamate (CDCPC) as the chiral selector for the enantioseparation of some chiral antifungal compounds was investigated. The CDCPC was bonded to 5 µm porous silica particles and the stationary phase packed into fused silica capillaries (250 mm x 75 µm I.D.) using the \"slurry method\". The column was used for the separation of twelve selected azole compounds in their enantiomers by capillary electrochromatography (CEC). To study chiral recognition, the mobile phase was modified changing the organic solvent, water content, buffer type, concentration, and pH. Each change resulted in the enhancement of specific interactions at the expense of others, leading to chiral recognition. Their effects on retention factors, enantiomeric resolution, and peak broadening are critically discussed. The developed methodology was used as an appropriate test bench to evaluate the stability of the stationary phase under different mobile phase conditions, demonstrating a remarkable enantioselective capacity even after several tens of hours of continuous use. The optimized CEC-UV method was very effective in the enantiomeric separation of seven out of twelve azole fungicides, totaling fourteen separated peaks in a single 30 min run analysis.</p></div>","PeriodicalId":93576,"journal":{"name":"Journal of chromatography open","volume":"5 ","pages":"Article 100126"},"PeriodicalIF":0.0,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772391724000136/pdfft?md5=309a4aeaa8f55db62489e6b21ec85e62&pid=1-s2.0-S2772391724000136-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140066898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shape-shifting molecule behaviour during comprehensive two-dimensional gas chromatography analysis—A review","authors":"Philip J. Marriott ,&nbsp;Yong Foo Wong ,&nbsp;Michelle S.S. Amaral ,&nbsp;Yuesong Wu","doi":"10.1016/j.jcoa.2024.100125","DOIUrl":"https://doi.org/10.1016/j.jcoa.2024.100125","url":null,"abstract":"<div><p>This research considers a number of molecular structural changes that have been reported in gas chromatography (GC), which take place during the chromatographic separation process of a molecule, and leads to an observation of an elevated baseline between the molecule and its product in a single column (1D) GC analysis. This phenomenon has been termed dynamic gas chromatography (DGC) in the case of interconverting compounds or reaction chromatography for a reaction process (RGC), and has also been referred to as forming a ‘bridge’. This is distinct from the conventional (dynamic) equilibrium process that defines chromatography. In order to observe this effect, the precursor (PRE) and product (PRO) must have resolvable peaks i.e., they must have a sufficient magnitude difference in their retention factors. Comprehensive two-dimensional gas chromatography (GC×GC) offers particular advantages to examine the nature of this elevated baseline phenomenon in the 2D space of GC×GC, provided the relative retentions of the respective PRE and PRO of the transformation are now resolved in the second dimension. This leads to the observation of what may appear as ‘streaking’ effects in the 2D plot, with theoretical terminal positions due to both the PRE and PRO components. These streaking effects should not be confused with adsorption (e.g., tailing) effects. The elevated baseline may comprise a single species, such as for a decomposition process, PRE → PRO, or may comprise more components such as when a reversible or interconversion process occurs, PRE ⇌ PRO. If degradation occurs in the heated injector, PRO may generate an elevated peak at its characteristic first and second column retention times (¹<em>t</em>_R and ²<em>t</em>_R) as more PRO is produced. Considerations of different shapes arising from the different processes and their kinetics will also be discussed. This review introduces general aspects of dynamic GC, with a range of applications reported for this phenomenon. The manner in which this on-column process may be illustrated in GC×GC analysis to produce certain patterns in the 2D space are highlighted. Two recent examples of rearrangements in essential oil samples and irreversible changes in pyrethrins are considered in more depth, and experimental details are provided for these two cases.</p></div>","PeriodicalId":93576,"journal":{"name":"Journal of chromatography open","volume":"5 ","pages":"Article 100125"},"PeriodicalIF":0.0,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772391724000124/pdfft?md5=9a36e09174505d4720e664c838dc4e23&pid=1-s2.0-S2772391724000124-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140016173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Separation of 4-substituted 5-methylpiracetam stereoisomers on polysaccharide-based chiral stationary phases","authors":"H. Kažoka,&nbsp;B. Turovska,&nbsp;T. Upmanis","doi":"10.1016/j.jcoa.2024.100122","DOIUrl":"https://doi.org/10.1016/j.jcoa.2024.100122","url":null,"abstract":"<div><p>Monitoring of stereoisomer content in samples containing chiral compounds with multiple chiral centers is an important and challenging task in chiral liquid chromatography. 4-Phenyl-5-methylpiracetam, containing two chiral centers, was used as model compound to explore the stereorecognition ability of polysaccharide-based chiral selectors. Initially, the chromatographic behavior of racemic 4-phenyl-5-methylpiracetam on nineteen commercially available polysaccharide-based chiral columns was tested with a mobile phase, consisting of a mixture of ethanol and <em>n</em>-hexane. The obtained results were analysed, and nine chiral phases were selected for further investigation of seven newly synthesized 4-substituted 5-methylpiracetam chiral separations. Our subsequent studies showed that chiral stationary phases based on amylose <em>tris</em>(5-chloro-2-methylphenylcarbamate) and amylose <em>tris</em>[(S)-α-methylbenzylcarbamate] posess higher ability for chiral recognition of stereoisomers of the studied analytes.</p></div>","PeriodicalId":93576,"journal":{"name":"Journal of chromatography open","volume":"5 ","pages":"Article 100122"},"PeriodicalIF":0.0,"publicationDate":"2024-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2772391724000094/pdfft?md5=c494e70d1dce58ddfe941cbffb422e59&pid=1-s2.0-S2772391724000094-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139985548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}