Analytica Chimica Acta: X最新文献

{"title":"Non-faradaic electrochemical impedimetric profiling of procalcitonin and C-reactive protein as a dual marker biosensor for early sepsis detection","authors":"Ambalika Sanjeev Tanak ,&nbsp;Badrinath Jagannath ,&nbsp;Yashaswee Tamrakar ,&nbsp;Sriram Muthukumar ,&nbsp;Shalini Prasad","doi":"10.1016/j.acax.2019.100029","DOIUrl":"https://doi.org/10.1016/j.acax.2019.100029","url":null,"abstract":"<div><p>In this work, we demonstrate a robust, dual marker, biosensing strategy for specific and sensitive electrochemical response of Procalcitonin and C-reactive protein in complex body fluids such as human serum and whole blood for the detection of sepsis. Enhanced sensitivity is achieved by leveraging the physicochemical properties of zinc oxide at the electrode-solution interface. Characterization techniques such as SEM, EDAX, AFM, FTIR and fluorescence microscopy were performed to ensure a suitable biosensing surface. The characteristic biomolecular interactions between the target analyte and specific capture probe is quantified through unique frequency signatures using non-faradaic electrochemical impedance spectroscopy (EIS). The developed biosensor demonstrated a detection limit of 0.10 ng mL⁻¹ for PCT in human serum and whole blood with an R² of 0.99 and 0.98 respectively. CRP demonstrated a detection limit of 0.10 μg mL⁻¹ in human serum and whole blood with an R² of 0.90 and 0.98 respectively. Cross-reactivity analysis demonstrated robust selectivity to PCT and CRP with negligible interaction to non-specific biomolecules. The novel aspect of this technology is the ability to fine-tune individual biomarkers response owing to the optimal frequency tuning capability. The developed biosensor requires an ultra-low sample volume of 10 μL without the need for sample dilution for rapid analysis. We envision the developed dual marker biosensor to be useful as a sepsis-screening device for prognostic monitoring.</p></div>","PeriodicalId":241,"journal":{"name":"Analytica Chimica Acta: X","volume":"3 ","pages":"Article 100029"},"PeriodicalIF":2.5,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.acax.2019.100029","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2826935","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":"Analytical considerations in the determination of uranium isotope ratios in solid uranium materials using laser ablation multi-collector ICP-MS","authors":"Michael Krachler,&nbsp;Zsolt Varga,&nbsp;Adrian Nicholl,&nbsp;Klaus Mayer","doi":"10.1016/j.acax.2019.100018","DOIUrl":"https://doi.org/10.1016/j.acax.2019.100018","url":null,"abstract":"<div><p>Validated analytical measurement protocols for the fast and accurate determination of the uranium (U) isotopic composition (²³⁴U, ²³⁵U, ²³⁶U, ²³⁸U) of solid nuclear materials were developed employing ns-laser ablation (LA) coupled to multi-collector ICP-MS. The accuracy of the analytical procedure was assured by frequent (<em>n</em> = 65) analysis of a pressed pellet of certified isotopic reference material CRM U-030 (∼3 wt% ²³⁵U). The expanded uncertainty (<em>k</em> = 2) for the <em>n</em>(²³⁵U)/<em>n</em>(²³⁸U) ratio was as low as 0.05%, rising to 0.62% and 1.09% for <em>n</em>(²³⁴U)/<em>n</em>(²³⁸U) and <em>n</em>(²³⁶U)/<em>n</em>(²³⁸U) ratios, respectively. LA-MC-ICP-MS measurements of a pressed pellet of certified isotopic reference material CRM U-020 (∼2 wt% ²³⁵U) before analysis of each sample allowed calculation of the ion counter gains and mass bias correction. Both individual spot analysis and line scan analysis were used to measure <em>n</em>(²³⁴U)/<em>n</em>(²³⁸U), <em>n</em>(²³⁵U)/<em>n</em>(²³⁸U), and <em>n</em>(²³⁶U)/<em>n</em>(²³⁸U) ratios in two low-enriched UO₂ pellets from the fourth Collaborative Materials Exercise (CMX-4), four seized low-enriched UO₂ pellets intercepted from illicit trafficking and one metal sample consisting of depleted U. LA-MC-ICP-MS results of all investigated samples matched well with U isotope ratios obtained by thermal ionisation mass spectrometry (TIMS). This independent confirmation of the LA-MC-ICP-MS results by TIMS underpinned the high quality of generated analytical data. Acquisition of several thousand data points within a couple of minutes during line scan analysis yielded detailed information on the spatial distribution of the U isotopic composition of selected UO₂ pellets, revealing straightforwardly their (in˗)homogeneity on the μm-scale. Calculating skewness and half width of the frequency distributions of the <em>n</em>(²³⁵U)/<em>n</em>(²³⁸U) amount ratio allowed the quantitative assessment of the (in-)homogeneity of the investigated samples. This information allows drawing conclusions on the starting materials used for the production of the pellets. From a nuclear forensics perspective, LA-MC-ICP-MS provides quick, accurate results on the spatial distribution of major and minor U isotopes while preserving the sample i.e. piece of evidence, essentially intact.</p></div>","PeriodicalId":241,"journal":{"name":"Analytica Chimica Acta: X","volume":"2 ","pages":"Article 100018"},"PeriodicalIF":2.5,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.acax.2019.100018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1506613","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":"Evaluation of the selectivity of G-quadruplex ligands in living cells with a small molecule fluorescent probe","authors":"Suge Zhang ,&nbsp;Hongxia Sun ,&nbsp;Dawei Yang ,&nbsp;Yan Liu ,&nbsp;Xiufeng Zhang ,&nbsp;Hongbo Chen ,&nbsp;Qian Li ,&nbsp;Aijiao Guan ,&nbsp;Yalin Tang","doi":"10.1016/j.acax.2019.100017","DOIUrl":"https://doi.org/10.1016/j.acax.2019.100017","url":null,"abstract":"<div><p>G-quadruplex has been an emerging target for drug design due to its physiologically important roles in oncology. A number of quadruplex-interactive ligands have been developed by synthetic and medicinal chemists over the past decades. However, the great challenge still remains that the method for detecting the specific targeting of these ligands to the G-quadruplex structures in cells is still lacking. Herein, a detection system for directly identifying the specific targeting of a ligand to DNA G-quadruplexes in cells was constructed by using a small-molecular fluorescent probe (IMT) as a fluorescent indicator. Four typical ligands have been successfully evaluated, demonstrating the promising application of this detection system in the screening and evaluation of quadruplex-specific therapeutic agents.</p></div>","PeriodicalId":241,"journal":{"name":"Analytica Chimica Acta: X","volume":"2 ","pages":"Article 100017"},"PeriodicalIF":2.5,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.acax.2019.100017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1746879","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":"A “turn-off” SERS aptasensor based DNAzyme-gold nanorod for ultrasensitive lead ion detection","authors":"Wei Xu ,&nbsp;Aiwu Zhao ,&nbsp;Fangtao Zuo ,&nbsp;Hafiz Muhammad Jafar Hussain ,&nbsp;Ranjha Khan","doi":"10.1016/j.acax.2019.100020","DOIUrl":"https://doi.org/10.1016/j.acax.2019.100020","url":null,"abstract":"<div><p>It is great significance to precisely monitor lead (II) ions (Pb²⁺) for environment protection and human health monitoring. We designed a sensitive detection strategy for sensitive and selective determination of Pb²⁺, based on a Pb²⁺-specific DNAzyme as the catalytic unit, Cy3-labeled DNA modified gold nanorods (AuNRs) as SERS reporter. Firstly, AuNRs surface were employed as a platform for the immobilization of thiolated probe DNA, and then hybridized with DNAzyme catalytic beacons. By taking advantage of DNAzyme digest, a molecular beacon, causes a “turn-off” SERS signal by disrupting the labeled probes. Under the optical conditions, the DNAzyme-AuNRs sensor system exhibited high sensitivity, acceptable stability and reproducibility with a wide linear range from 0.5 to 100 nM (R² = 0.9973), and an ultra-low detection limit of 0.01 nM. The proposed strategy has additional advantages of being less time-consuming, low-cost and remote query, and avoids the interference of some metals such as Fe³⁺, Cd²⁺, Ba²⁺, Cu²⁺, Zn²⁺. The SERS biosensor system has been successfully applied for detecting Pb²⁺ in real samples with a satisfactory result. The result indicated that the proposed sensing strategy not only enriches SERS platform of monitoring Pb²⁺ but also exhibits potential for the point-of-care diagnostic application of the clinical screening in complicated biological samples.</p></div>","PeriodicalId":241,"journal":{"name":"Analytica Chimica Acta: X","volume":"2 ","pages":"Article 100020"},"PeriodicalIF":2.5,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.acax.2019.100020","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3343923","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":"Rational design of mixtures for chromatographic peak tracking applications via multivariate selectivity","authors":"Daniel W. Cook ,&nbsp;Kelson G. Oram ,&nbsp;Sarah C. Rutan ,&nbsp;Dwight R. Stoll","doi":"10.1016/j.acax.2019.100010","DOIUrl":"https://doi.org/10.1016/j.acax.2019.100010","url":null,"abstract":"<div><p>Chromatographic characterization and parameterization studies targeting many solutes require the judicious choice of operating conditions to minimize analysis time without compromising the accuracy of the results. To minimize analysis time, solutes are often grouped into a small number of mixtures; however, this increases the risk of peak overlap. While multivariate curve resolution methods are often able to resolve analyte signals based on their spectral qualities, these methods require that the chromatographically overlapped compounds have dissimilar spectra. In this work, a strategy for grouping compounds into sample mixtures containing solutes with distinct spectral and, optionally, with distinct chromatographic properties, in order to ensure successful solute resolution either chromatographically or with curve resolution methods is proposed. We name this strategy rational design of mixtures (RDM). RDM utilizes multivariate selectivity as a metric for making decisions regarding group membership (<em>i.e.</em>, whether to add a particular solute to a particular sample). A group of 97 solutes was used to demonstrate this strategy. Utilizing both estimated chromatographic properties and measured spectra to group these 97 analytes, only 12 groups were required to avoid a situation where two or more solutes in the same group could not be resolved either chromatographically <em>(i.e.</em>, they have significantly different retention times) or spectrally (i.e., spectra are different enough to enable resolution by curve resolution methods). When only spectral properties were utilized (<em>i.e.</em>, the chromatographic properties are unknown ahead of time) the number of groups required to avoid unresolvable overlaps increased to 20. The grouping strategy developed here will improve the time and instrument efficiency of studies that aim to obtain retention data for solutes as a function of operating conditions, whether for method development or determination of the chromatographic parameters of solutes of interest (<em>e.g.</em>, <em>k</em>_<em>w</em>).</p></div>","PeriodicalId":241,"journal":{"name":"Analytica Chimica Acta: X","volume":"2 ","pages":"Article 100010"},"PeriodicalIF":2.5,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.acax.2019.100010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1969175","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":"An electrochemical study of acrylate bone adhesive permeability and selectivity change during in vitro ageing: A model approach to the study of biomaterials and membrane barriers","authors":"M. Raja ,&nbsp;J.C. Shelton ,&nbsp;F. Salamat-Zadeh ,&nbsp;M. Tavakoli ,&nbsp;S. Donell ,&nbsp;G. Watts ,&nbsp;P. Vadgama","doi":"10.1016/j.acax.2019.100009","DOIUrl":"https://doi.org/10.1016/j.acax.2019.100009","url":null,"abstract":"<div><p>This study assessed the solute permeability of a family of UV and moisture cured acrylates-based adhesives during <em>in vitro</em> ageing in pH 7.4 buffer. Acrylates have a potential role in bone fracture fixation, but their inability to allow microsolute exchange between the fractured bone surfaces may contribute to ineffective healing. Cyclic voltammetry and chronoamperometry were used to determine the diffusion coefficients for various electrochemically active probe molecules (O_2, H₂O₂, acetaminophen, catechol, uric acid and ascorbic acid) at proprietary acrylic, urethane – acrylate and cyanoacrylate adhesives. All adhesives proved to be impermeable for up to 9 days ageing, following which a near-exponential increase in permeability resulted for all solutes. At 18 days, the diffusion coefficients were in the range of 10⁻⁵ cm²s⁻¹ for O₂ and H₂O₂ and 10⁻⁶ cm²s⁻¹ for the organic solutes; no transport selectivity was seen between the latter. Adhesive joint strength showed a direct, inverse, correlation with permeability, with the more hydrophilic cyanoacrylates showing the greatest loss of strength. Adhesive permeabilisation does not appear to be compatible with the retention of bonding strength, but it serves as a new non-destructive predictor of adhesion strength change during ageing and practical use.</p></div>","PeriodicalId":241,"journal":{"name":"Analytica Chimica Acta: X","volume":"2 ","pages":"Article 100009"},"PeriodicalIF":2.5,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.acax.2019.100009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1506755","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":"Influencing the selectivity of grafted anion exchangers utilizing the solubility of the radical initiator during the graft process","authors":"Achim Kaltz,&nbsp;Lea Bohra,&nbsp;Jonathan S. Tripp,&nbsp;Andreas Seubert","doi":"10.1016/j.acax.2019.100019","DOIUrl":"https://doi.org/10.1016/j.acax.2019.100019","url":null,"abstract":"<div><p>A previously published radical graft-functionalization method for the synthesis of high performance anion exchangers was further investigated to control the capacity and selectivity of the exchangers. Using a hydrophobic radical initiator instead of a hydrophilic one diminished the influence of rivaling homopolymerization of monomer during the functionalization step. Instead of only generating monomer radicals in free solution the radicals are ideally generated on top of the PS/DVB surface. However, in both cases the selectivity factors of polarizable anions bromide and nitrate in relation to chloride increased strongly with increasing capacity of the exchanger. Higher exchanger capacities could lead to coelution of bromide and/or nitrate with other analytes such as sulfate or phosphate when using the eluent as proposed in this work. By variation of the organic solvent used for functionalization it was possible to remove both the rivaling homopolymerization and the strong influence of the capacity on the selectivity. With increasing solubility of the hydrophobic radical initiator in the organic solvent the influence of the homopolymerization and the influence on the selectivity factor of bromide and nitrate decreased. Additionally, a change of bromate selectivity factor could be observed. The bromate signal is shifted closer towards the chloride signal. However, with increasing solubility of the radical initiator in the organic solvent the observed capacity of the exchangers decreases linearly, resulting in higher amounts of monomer needed for functionalization.</p></div>","PeriodicalId":241,"journal":{"name":"Analytica Chimica Acta: X","volume":"2 ","pages":"Article 100019"},"PeriodicalIF":2.5,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.acax.2019.100019","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3343922","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":"Origin of the selectivity differences of aromatic alcohols and amines of different n-alkyl chain length separated with perfluorinated C8 and bidentated C8 modified silica hydride stationary phases","authors":"Chadin Kulsing ,&nbsp;Yada Nolvachai ,&nbsp;Maria T. Matyska ,&nbsp;Joseph J. Pesek ,&nbsp;Joshua Topete ,&nbsp;Reinhard I. Boysen ,&nbsp;Milton T.W. Hearn","doi":"10.1016/j.acax.2018.100003","DOIUrl":"https://doi.org/10.1016/j.acax.2018.100003","url":null,"abstract":"<div><p>Perfluorinated C8-(PerfluoroC8) and bidentate anchored C8-(BDC8)-modified silica hydride stationary phases have been employed for the isocratic separation of homologous phenylalkanols and phenylalkylamines differing in their <em>n</em>-alkyl chain length, using aqueous-acetonitrile (ACN) mobile phases of different ACN contents from 10 to 90% (v/v) in 10% increments. These analytes showed reversed-phase (RP) retention behaviour with mobile phases of &lt;40% (v/v) ACN content with both stationary phases but with the BDC8 stationary phase providing longer retention. The PerfluoroC8, but not the BDC8, stationary phase also exhibited significant retention of these analytes under conditions typical of an aqueous normal phase (ANP) mode (<em>i.e.</em> with mobile phases of &gt;80% (v/v) ACN content), with the analytes exhibiting overall U-shape retention dependencies on the ACN content of the mobile phase. Further, these stationary phases showed differences in their selectivity behaviour with regard to the <em>n</em>-alkyl chain lengths of the different analytes. These observations could not be explained in terms of p<em>K</em>_<em>a</em>, log <em>P</em>, molecular mass or linear solvation energy concepts. However, density functional theory (DFT) simulations provided a possible explanation for the observed selectivity trends, namely differences in the molecular geometries and structural organisation of the immobilised ligands of these two stationary phases under different solvational conditions. For mobile phase conditions favouring the RP mode, these DFT simulations revealed that interactions between adjacent BDC8 ligands occur, leading to a stationary phase with a more hydrophobic surface. Moreover, under mobile phase conditions favouring retention of the analytes in an ANP mode, these interactions of the bidentate-anchored C8 ligands resulted in hindered analyte access to potential ANP binding sites on the BDC8 stationary phase surface. With the PerfluoroC8 stationary phase, the DFT simulations revealed strong repulsion of individual perfluoroC8 ligand chains, with the perfluoroC8 ligands of this stationary phase existing in a more open brush-like state (and with a less hydrophobic surface) compared to the BDC8 ligands. These DFT simulation results anticipated the chromatographic findings that the phenylalkanols and phenylalkylamines had reduced retention in the RP mode with the PerfluoroC8 stationary phase. Moreover, the more open ligand structure of the PerfluoroC8 stationary phase enabled greater accessibility of the analytes to water solvated binding sites on the stationary phase surface under mobile phase conditions favouring an ANP retention mode, leading to retention of the analytes, particularly the smaller phenylalkylamines, <em>via</em> hydrogen bonding and electrostatic effects.</p></div>","PeriodicalId":241,"journal":{"name":"Analytica Chimica Acta: X","volume":"1 ","pages":"Article 100003"},"PeriodicalIF":2.5,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.acax.2018.100003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3343926","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":"Potential of ion mobility-mass spectrometry for both targeted and non-targeted analysis of phase II steroid metabolites in urine","authors":"Maykel Hernández-Mesa,&nbsp;Fabrice Monteau,&nbsp;Bruno Le Bizec,&nbsp;Gaud Dervilly-Pinel","doi":"10.1016/j.acax.2019.100006","DOIUrl":"https://doi.org/10.1016/j.acax.2019.100006","url":null,"abstract":"<div><p>In recent years, the commercialization of hybrid ion mobility-mass spectrometers and their integration in traditional LC-MS workflows provide new opportunities to extend the current boundaries of targeted and non-targeted analyses. When coupled to LC-MS, ion mobility spectrometry (IMS) provides a novel characterization parameter, the so-called averaged collision cross section (CCS, Ω), as well as improves method selectivity and sensitivity by the separation of isobaric and isomeric molecules and the isolation of the analytes of interest from background noise. In this work, we have explored the potential and advantages of this technology for carrying out the determination of phase II steroid metabolites (i.e. androgen and estrogen conjugates, including glucuronide and sulfate compounds; n = 25) in urine samples. These molecules have been selected based on their relevance in the fields of chemical food safety and doping control, as well as in metabolomics studies. The influence of urine matrix on the CCS of steroid metabolites was evaluated in order to give more confidence to current CCS databases and support its use as complementary information to retention time (Rt) and mass spectra for compound identification. Samples were only diluted 10-fold with aqueous formic acid (0.1%, v/v) prior analysis. Only an almost insignificant effect of adult bovine urine matrix on the CCS of certain steroid metabolites was observed in comparison with calve urine matrix, which is a less complex sample. In addition, high accuracy was achieved for CCS measurements carried out over four months (ΔCCS &lt; 1.3% for 99.8% of CCS measurements; n = 1806). Interestingly, it has been observed that signal-to-noise (S/N) ratio could be improved at least 2 or 7-fold when IMS is combined with LC-MS. In addition to the separation of isomeric steroid pairs (i.e. etiocholanolone glucuronide and epiandrosterone glucuronide, as well as 19-noretiocholanolone glucuronide and 19-norandrosterone glucuronide), steroid-based ions were also separated in the IMS dimension from co-eluting matrix compounds that presented similar mass-to-charge ratio (<em>m/z</em>). Finally, based on CCS measurements and as a proof of concept, 17α-boldenone glucuronide has been identified as one of the main metabolites resulted from boldione administration to calves.</p></div>","PeriodicalId":241,"journal":{"name":"Analytica Chimica Acta: X","volume":"1 ","pages":"Article 100006"},"PeriodicalIF":2.5,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.acax.2019.100006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"2096500","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":"Extraction of hydrophobic analytes from organic solution into a titanate 2D-nanosheet host: Electroanalytical perspectives","authors":"Wulan Tri Wahyuni ,&nbsp;Budi Riza Putra ,&nbsp;Christian Harito ,&nbsp;Dmitry V. Bavykin ,&nbsp;Frank C. Walsh ,&nbsp;Philip J. Fletcher ,&nbsp;Frank Marken","doi":"10.1016/j.acax.2018.100001","DOIUrl":"https://doi.org/10.1016/j.acax.2018.100001","url":null,"abstract":"<div><p>Titanate nanosheets (single layer, typically 200 nm lateral size) deposited from aqueous colloidal solution onto electrode surfaces form lamellar hosts that bind redox active molecular redox probes. Here, hydrophobic redox systems such as anthraquinone, 1-amino-anthraquinone, deca-methylferrocene, 5,10,15,20-tetraphenyl-21<em>H</em>,23<em>H</em>-porphine manganese (III) chloride (TPPMnCl), and α-tocopherol are shown to bind directly from cyclopentanone solution (and from other types of organic solvents) into the titanate nanosheet film. For anthraquinone derivatives, stable voltammetric responses are observed in aqueous media consistent with 2-electron 2-proton reduction, however, independent of the pH of the outside solution phase environments. For decamethylferrocene a gradual decay of the voltammetric response is observed, but for TPPMnCl a more stable voltammetric signal is seen when immersed in chloride containing (NaCl) electrolyte. α-Tocopherol exhibits chemically irreversible oxidation and is detected with 1 mM–20 mM linear range and approximately 10⁻³ M concentration limit of detection. All redox processes exhibit an increase in current with increasing titanate film thickness and with increasing external electrolyte concentration. This and other observations suggest that important factors are analyte concentration and mobility within the titanate host, as well as ion exchange between titanate nanosheets and the outside electrolyte phase to maintain electroneutrality during voltammetric experiments. The lamellar titanate (with embedded tetrabutyl-ammonium cations) behaves like a hydrophobic host (for hydrophobic redox systems) similar to hydrophobic organic microphase systems. Potential for analytical applications is discussed.</p></div>","PeriodicalId":241,"journal":{"name":"Analytica Chimica Acta: X","volume":"1 ","pages":"Article 100001"},"PeriodicalIF":2.5,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.acax.2018.100001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3343924","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}