Pub Date : 2025-03-28DOI: 10.1021/acs.analchem.4c06496
Ondřej Peterka, Yasmin Kadyrbekova, Robert Jirásko, Zuzana Lásko, Bohuslav Melichar, Michal Holčapek
Chemical derivatization involves the reaction of an analyte with a derivatization agent to modify its structure, improving the peak shape, chromatographic performance, structural analysis, ionization efficiency, and sensitivity. A novel derivatization method using 3-(chlorosulfonyl)benzoic acid is developed for the determination of monoacylglycerols, diacylglycerols, free sterols, and tocopherols using the reversed-phase ultra-high-performance liquid chromatography–tandem mass spectrometry (RP-UHPLC/MS/MS) method in the negative ion mode. The chromatographic and mass spectrometric properties of derivatized lipids are investigated by using 29 lipid standards spanning four lipid classes. The derivatization process is optimized using pooled plasma spiked by 9 internal standards, achieving an optimal yield with a reaction time of 40 min at 60 °C. The stability of the derivatives is confirmed, with short-term stability maintained for 10 h at 4 °C and long-term stability preserved for 5 days at −80 °C. The repeatability and reproducibility are verified by one/two operator(s), which underscores the simplicity and robustness of the method, and calibration curves with high linear regression coefficients illustrate the accuracy of the method. The derivatization approach, which combines RP-UHPLC/MS/MS and the use of specific fragmentation patterns, significantly reduces limits of detection, reaching 15–25 pmol/mL for free sterols in plasma. The optimized method is applied to the analysis of human plasma, leading to the identification of 92 lipid species in the targeted lipid classes. This represents a substantial improvement in sensitivity and detection capabilities compared to those of previously reported methods.
{"title":"Novel Charge-Switch Derivatization Method Using 3-(Chlorosulfonyl)benzoic Acid for Sensitive RP-UHPLC/MS/MS Analysis of Acylglycerols, Sterols, and Prenols","authors":"Ondřej Peterka, Yasmin Kadyrbekova, Robert Jirásko, Zuzana Lásko, Bohuslav Melichar, Michal Holčapek","doi":"10.1021/acs.analchem.4c06496","DOIUrl":"https://doi.org/10.1021/acs.analchem.4c06496","url":null,"abstract":"Chemical derivatization involves the reaction of an analyte with a derivatization agent to modify its structure, improving the peak shape, chromatographic performance, structural analysis, ionization efficiency, and sensitivity. A novel derivatization method using 3-(chlorosulfonyl)benzoic acid is developed for the determination of monoacylglycerols, diacylglycerols, free sterols, and tocopherols using the reversed-phase ultra-high-performance liquid chromatography–tandem mass spectrometry (RP-UHPLC/MS/MS) method in the negative ion mode. The chromatographic and mass spectrometric properties of derivatized lipids are investigated by using 29 lipid standards spanning four lipid classes. The derivatization process is optimized using pooled plasma spiked by 9 internal standards, achieving an optimal yield with a reaction time of 40 min at 60 °C. The stability of the derivatives is confirmed, with short-term stability maintained for 10 h at 4 °C and long-term stability preserved for 5 days at −80 °C. The repeatability and reproducibility are verified by one/two operator(s), which underscores the simplicity and robustness of the method, and calibration curves with high linear regression coefficients illustrate the accuracy of the method. The derivatization approach, which combines RP-UHPLC/MS/MS and the use of specific fragmentation patterns, significantly reduces limits of detection, reaching 15–25 pmol/mL for free sterols in plasma. The optimized method is applied to the analysis of human plasma, leading to the identification of 92 lipid species in the targeted lipid classes. This represents a substantial improvement in sensitivity and detection capabilities compared to those of previously reported methods.","PeriodicalId":27,"journal":{"name":"Analytical Chemistry","volume":"183 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stimulated emission depletion microscopy (STED) achieves resolution beyond the diffraction limit by employing a donut-shaped depletion laser that selectively reduces fluorescence at the periphery of the excitation area. The imaging quality of STED microscopy is closely tied to minimizing the intermediate light from the ring-depletion laser. In this study, we introduce a method termed “digital redepleted STED,” which uses frequency domain filtering to generate an optimal donut profile by subtracting the “perfect donut” signal from the original STED data. This approach effectively reduces background noise and enhances the STED resolution. Through simulation experiments, we demonstrate that digitally redepleted STED doubled the resolution. This method is compatible with a wide range of biological samples and can be adapted for two-organelle-structure STED and 3D STED applications. We compare the performance of digitally redepleted STED with that of digitally enhanced STED (De STED) and deconvolution methods (STED Decon) in terms of the signal-to-background ratio (SBR) and resolution as evaluation metrics, and we find that our method doubled the resolution and SBR for different samples compared with origin STED. Our results indicate that digitally redepleted STED outperforms both De STED and STED Decon for complicated sample like mitochondria. We anticipate that the digitally redepleted STED will have broad applicability due to its enhanced resolution, improved SBR, and ease of implementation.
{"title":"Digital Redepleted of Stimulated Emission Depletion Microscopy for Noise Reduction and Resolution Improvement","authors":"Xinwei Gao, Yong Guo, Luwei Wang, Yue Chen, Xiangcong Xu, Lukui Xu, Xiaoyu Weng, Wei Yan, Junle Qu","doi":"10.1021/acs.analchem.5c00101","DOIUrl":"https://doi.org/10.1021/acs.analchem.5c00101","url":null,"abstract":"Stimulated emission depletion microscopy (STED) achieves resolution beyond the diffraction limit by employing a donut-shaped depletion laser that selectively reduces fluorescence at the periphery of the excitation area. The imaging quality of STED microscopy is closely tied to minimizing the intermediate light from the ring-depletion laser. In this study, we introduce a method termed “digital redepleted STED,” which uses frequency domain filtering to generate an optimal donut profile by subtracting the “perfect donut” signal from the original STED data. This approach effectively reduces background noise and enhances the STED resolution. Through simulation experiments, we demonstrate that digitally redepleted STED doubled the resolution. This method is compatible with a wide range of biological samples and can be adapted for two-organelle-structure STED and 3D STED applications. We compare the performance of digitally redepleted STED with that of digitally enhanced STED (De STED) and deconvolution methods (STED Decon) in terms of the signal-to-background ratio (SBR) and resolution as evaluation metrics, and we find that our method doubled the resolution and SBR for different samples compared with origin STED. Our results indicate that digitally redepleted STED outperforms both De STED and STED Decon for complicated sample like mitochondria. We anticipate that the digitally redepleted STED will have broad applicability due to its enhanced resolution, improved SBR, and ease of implementation.","PeriodicalId":27,"journal":{"name":"Analytical Chemistry","volume":"26 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-28DOI: 10.1021/acs.analchem.5c00138
Zhihao Zhang, Huaiwen Cang, Qingyun Li, Yi Yu, Huimin Jiao, Yuanyuan Xie, Shan Deng, Jichun Jiang, Lei Hua, Haiyang Li, Hang Li
Rapid and highly frequent measurements of exhaled breath hold significant value for disease diagnosis and exposure assessments. Direct inlet mass spectrometry and ion mobility spectrometry demonstrate great potential for on-site breath analysis, but their accuracy and sensitivity are notably affected by the high humidity in the breath samples. A miniature and continuous dehydration device based on dual-switching thermoelectric cold traps has been developed to efficiently reduce the humidity of breath gas from saturation to relative humidity of 4.3%, and a subcooling compensation method was adopted to eliminate the humidity fluctuations when switching the two cold traps to remove the condensed water in the trap, which could achieve a stable outlet humidity with RSD of 8.2% regardless of inlet humidity variations. The performance and profits of the miniature dehydration device for on-site analysis of breath samples have been tested by coupling with direct inlet photoionization ion mobility spectrometry and time-of-flight mass spectrometry. Trace breath acetone could be directly measured, and its concentration profiles over an 8 h period in fasting volunteers could be continuously monitored every 30 s. Furthermore, the m/z peaks from chlorinated hydrocarbons in exhaled breath samples were clearly identified after passing the dehydration device, which can be used for an occupational health assessment of the widely used halocarbon solvents.
{"title":"Miniature Thermoelectric Cooler for Long-Term Stable Dehydration for On-Site Breath Analysis by Direct Inlet Photoionization Ion Mobility Spectrometry and Mass Spectrometry","authors":"Zhihao Zhang, Huaiwen Cang, Qingyun Li, Yi Yu, Huimin Jiao, Yuanyuan Xie, Shan Deng, Jichun Jiang, Lei Hua, Haiyang Li, Hang Li","doi":"10.1021/acs.analchem.5c00138","DOIUrl":"https://doi.org/10.1021/acs.analchem.5c00138","url":null,"abstract":"Rapid and highly frequent measurements of exhaled breath hold significant value for disease diagnosis and exposure assessments. Direct inlet mass spectrometry and ion mobility spectrometry demonstrate great potential for on-site breath analysis, but their accuracy and sensitivity are notably affected by the high humidity in the breath samples. A miniature and continuous dehydration device based on dual-switching thermoelectric cold traps has been developed to efficiently reduce the humidity of breath gas from saturation to relative humidity of 4.3%, and a subcooling compensation method was adopted to eliminate the humidity fluctuations when switching the two cold traps to remove the condensed water in the trap, which could achieve a stable outlet humidity with RSD of 8.2% regardless of inlet humidity variations. The performance and profits of the miniature dehydration device for on-site analysis of breath samples have been tested by coupling with direct inlet photoionization ion mobility spectrometry and time-of-flight mass spectrometry. Trace breath acetone could be directly measured, and its concentration profiles over an 8 h period in fasting volunteers could be continuously monitored every 30 s. Furthermore, the <i>m</i>/<i>z</i> peaks from chlorinated hydrocarbons in exhaled breath samples were clearly identified after passing the dehydration device, which can be used for an occupational health assessment of the widely used halocarbon solvents.","PeriodicalId":27,"journal":{"name":"Analytical Chemistry","volume":"59 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-28DOI: 10.1021/acs.analchem.4c06427
Heeyeong Jang, Supreeth Setty, Chong Ahn
Although the most commonly used method for enhancing a limit of detection (LoD) in immunoassay is adopting chemiluminescence (CL), the liquid form of CL substrates has hindered its use for rapid diagnostic testing (RDT). In order to use the CL-based immunoassay in RDT with minimal user intervention, the liquid CL substrate should be converted to a dry form. In addition, a new RDT platform that is able to perform two sequential flows needs to be developed for the sequential flow control of the CL substrate. In this work, we have successfully developed a new dry form of CL substrate on the strip using a lyophilization process, as well as new lateral flow strips using an additional membrane pad for a time delay to achieve the desired sequential dual flows. Thus, on the dual-flow RDT strips, first the detection antibody conjugated with an enzyme flows over the test and control lines, and then the reconstituted CL substrate flows later. A hydrophilic PVDF membrane was selected as a pad material for the time delay to achieve the sequential dual flows through two flow paths, and flow introduction timing was functionally controlled to secure the time delay of approximately 5 minutes desired between the two flows. A CL-based cardiac troponin I (cTnI) assay was successfully performed on the new dual-flow RDT platform with a sample volume of 120 μL, achieving a LoD of 100 pg/mL. The achieved LoD is better than those possible with most of the currently available RDTs on the market. The new CL-based RDT platform with the capability of dual flows developed in this work can be used for numerous other immunodiagnostic platforms which need further high-sensitivity detection, envisaging a new RDT platform for point-of-care testing with further quantitative analysis.
{"title":"A New Chemiluminescence-Based Rapid Diagnostic Testing Platform with Sequential Dual-Flow Strips for Cardiac Troponin I (cTnI)","authors":"Heeyeong Jang, Supreeth Setty, Chong Ahn","doi":"10.1021/acs.analchem.4c06427","DOIUrl":"https://doi.org/10.1021/acs.analchem.4c06427","url":null,"abstract":"Although the most commonly used method for enhancing a limit of detection (LoD) in immunoassay is adopting chemiluminescence (CL), the liquid form of CL substrates has hindered its use for rapid diagnostic testing (RDT). In order to use the CL-based immunoassay in RDT with minimal user intervention, the liquid CL substrate should be converted to a dry form. In addition, a new RDT platform that is able to perform two sequential flows needs to be developed for the sequential flow control of the CL substrate. In this work, we have successfully developed a new dry form of CL substrate on the strip using a lyophilization process, as well as new lateral flow strips using an additional membrane pad for a time delay to achieve the desired sequential dual flows. Thus, on the dual-flow RDT strips, first the detection antibody conjugated with an enzyme flows over the test and control lines, and then the reconstituted CL substrate flows later. A hydrophilic PVDF membrane was selected as a pad material for the time delay to achieve the sequential dual flows through two flow paths, and flow introduction timing was functionally controlled to secure the time delay of approximately 5 minutes desired between the two flows. A CL-based cardiac troponin I (<i>cTnI</i>) assay was successfully performed on the new dual-flow RDT platform with a sample volume of 120 μL, achieving a LoD of 100 pg/mL. The achieved LoD is better than those possible with most of the currently available RDTs on the market. The new CL-based RDT platform with the capability of dual flows developed in this work can be used for numerous other immunodiagnostic platforms which need further high-sensitivity detection, envisaging a new RDT platform for point-of-care testing with further quantitative analysis.","PeriodicalId":27,"journal":{"name":"Analytical Chemistry","volume":"49 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Low-γ nuclei signal enhancement in solid-state NMR spectroscopy is typically achieved via cross-polarization (CP) using abundant 1H polarization in organic solids. Nevertheless, direct low-γ nuclei signal detection via a single CP process is quite challenging with minute quantities of samples due to the extremely limited signal-to-noise ratio (SNR) of the acquired spectra. Herein, we demonstrated the robust performance of a multiple-contact CP experiment with multiple acquisition periods (MCP) in each transient scan, leading to several-fold SNR enhancement over a conventional single-CP experiment at fast MAS conditions with slightly increased experimental time. Spin thermodynamic analysis was further performed to achieve maximum SNR by adding the obtained Nmax CP spectra from each transient, where Nmax ∼ T1ρ/τcw. Here, T1ρ is the proton spin–lattice relaxation time in the rotating frame, and τcw is the total time of CP and a heteronuclear decoupling period. The theoretical analysis is in good agreement with experimental results, and more than 4.5-fold SNR enhancement can be achieved for the pharmaceutical danazol/vanillin cocrystals. Besides, MCP was also used for proton T1 and T1ρ measurement with high-resolution 13C detection, where both proton T1 and T1ρ can serve as the spectral-editing basis to identify different immiscible components in complex molecular systems.
{"title":"Direct Detection of Natural-Abundance Low-γ Nuclei NMR Signals of Minute Quantities of Organic Solids","authors":"Zhiwei Yan, Jiangying Li, Hailu Zhang, Rongchun Zhang","doi":"10.1021/acs.analchem.4c06887","DOIUrl":"https://doi.org/10.1021/acs.analchem.4c06887","url":null,"abstract":"Low-γ nuclei signal enhancement in solid-state NMR spectroscopy is typically achieved via cross-polarization (CP) using abundant <sup>1</sup>H polarization in organic solids. Nevertheless, direct low-γ nuclei signal detection via a single CP process is quite challenging with minute quantities of samples due to the extremely limited signal-to-noise ratio (SNR) of the acquired spectra. Herein, we demonstrated the robust performance of a multiple-contact CP experiment with multiple acquisition periods (MCP) in each transient scan, leading to several-fold SNR enhancement over a conventional single-CP experiment at fast MAS conditions with slightly increased experimental time. Spin thermodynamic analysis was further performed to achieve maximum SNR by adding the obtained <i>N</i><sub>max</sub> CP spectra from each transient, where <i>N</i><sub>max</sub> ∼ <i>T</i><sub>1ρ</sub>/<i>τ</i><sub>cw</sub>. Here, <i>T</i><sub>1ρ</sub> is the proton spin–lattice relaxation time in the rotating frame, and <i>τ</i><sub>cw</sub> is the total time of CP and a heteronuclear decoupling period. The theoretical analysis is in good agreement with experimental results, and more than 4.5-fold SNR enhancement can be achieved for the pharmaceutical danazol/vanillin cocrystals. Besides, MCP was also used for proton <i>T</i><sub>1</sub> and <i>T</i><sub>1ρ</sub> measurement with high-resolution <sup>13</sup>C detection, where both proton <i>T</i><sub>1</sub> and <i>T</i><sub>1ρ</sub> can serve as the spectral-editing basis to identify different immiscible components in complex molecular systems.","PeriodicalId":27,"journal":{"name":"Analytical Chemistry","volume":"10 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-28DOI: 10.1021/acs.analchem.4c06656
Qing Dong, Xu Sun, Yuling Wang, Wei Zhang, Fan Feng, Dan Li, Jin Wang, Erkang Wang
Exosomes carry various biological information and are abundant in body fluids, making them a promising noninvasive biomarker for disease diagnosis and prognosis. However, current detection methods have limitations in sensitivity, specificity, and cost effectiveness, hindering their clinical application. To address these challenges, we have developed a fast, accurate, and cost-effective method for detecting exosomes with high sensitivity and specificity, making it ideal for clinical applications. Clusters of differentiation 63 (CD63) aptamer with its complementary DNA (CD63 aptamer/cDNA) linked to streptavidin-coated magnetic beads (SA-MBs) are used as a capture probe. Exosomes with CD63 proteins can bind to the aptamer and release the cDNA, which initiates rolling circle amplification (RCA) to magnify the cDNA copies. The negatively charged RCA products induce the aggregation of positively charged spermine-modified silver nanoparticles (AgNPs) through electrostatic attraction. The aggregation of AgNPs can be observed visually with the naked eye or quantitatively analyzed using ultraviolet–visible (UV–vis) spectroscopy to determine the concentration of exosomes, with limits of detection of 4.0 × 104 particles/mL for visual observation and 800 particles/mL for UV–vis spectroscopy, respectively. The method has also been demonstrated for detecting the exosomes in serum samples, indicating its potential for clinical use in liquid biopsy.
{"title":"Enabling Sensitive Quantification of Exosomes Combining Aptamer-Based Rolling Circle Amplification and Silver Nanoparticles","authors":"Qing Dong, Xu Sun, Yuling Wang, Wei Zhang, Fan Feng, Dan Li, Jin Wang, Erkang Wang","doi":"10.1021/acs.analchem.4c06656","DOIUrl":"https://doi.org/10.1021/acs.analchem.4c06656","url":null,"abstract":"Exosomes carry various biological information and are abundant in body fluids, making them a promising noninvasive biomarker for disease diagnosis and prognosis. However, current detection methods have limitations in sensitivity, specificity, and cost effectiveness, hindering their clinical application. To address these challenges, we have developed a fast, accurate, and cost-effective method for detecting exosomes with high sensitivity and specificity, making it ideal for clinical applications. Clusters of differentiation 63 (CD63) aptamer with its complementary DNA (CD63 aptamer/cDNA) linked to streptavidin-coated magnetic beads (SA-MBs) are used as a capture probe. Exosomes with CD63 proteins can bind to the aptamer and release the cDNA, which initiates rolling circle amplification (RCA) to magnify the cDNA copies. The negatively charged RCA products induce the aggregation of positively charged spermine-modified silver nanoparticles (AgNPs) through electrostatic attraction. The aggregation of AgNPs can be observed visually with the naked eye or quantitatively analyzed using ultraviolet–visible (UV–vis) spectroscopy to determine the concentration of exosomes, with limits of detection of 4.0 × 10<sup>4</sup> particles/mL for visual observation and 800 particles/mL for UV–vis spectroscopy, respectively. The method has also been demonstrated for detecting the exosomes in serum samples, indicating its potential for clinical use in liquid biopsy.","PeriodicalId":27,"journal":{"name":"Analytical Chemistry","volume":"99 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-28DOI: 10.1021/acs.analchem.4c04676
Nir Galili, Anna Somlyay, Giorgia Aquila, Reto Wijker, Philip Gautschi, Lukas Wacker, Jordon D. Hemingway
We introduce a novel high-precision method for oxygen-isotope analysis of iron (oxyhydr)oxides using high-temperature conversion isotope ratio mass spectrometry (HTC-IRMS). In this approach, a finely ground mixture of iron (oxyhydr)oxide and graphite is heated at 1450 °C in a helium flow environment, converting oxygen to CO gas with nearly 100% yield. Continuous-flow IRMS analysis of the liberated CO yields a precision of ±0.15‰ (1σ, n = 28) and shows excellent agreement with (and improved precision over) traditional fluorination methods. This practical and safe technique expands access to oxygen-isotope measurements of iron oxides, thereby enhancing their utility in Earth and environmental sciences.
{"title":"High-Precision Oxygen-Isotope Analysis of Iron (Oxyhydr)oxides Using High-Temperature Conversion Isotope Ratio Mass Spectrometry","authors":"Nir Galili, Anna Somlyay, Giorgia Aquila, Reto Wijker, Philip Gautschi, Lukas Wacker, Jordon D. Hemingway","doi":"10.1021/acs.analchem.4c04676","DOIUrl":"https://doi.org/10.1021/acs.analchem.4c04676","url":null,"abstract":"We introduce a novel high-precision method for oxygen-isotope analysis of iron (oxyhydr)oxides using high-temperature conversion isotope ratio mass spectrometry (HTC-IRMS). In this approach, a finely ground mixture of iron (oxyhydr)oxide and graphite is heated at 1450 °C in a helium flow environment, converting oxygen to CO gas with nearly 100% yield. Continuous-flow IRMS analysis of the liberated CO yields a precision of ±0.15‰ (1σ, <i>n</i> = 28) and shows excellent agreement with (and improved precision over) traditional fluorination methods. This practical and safe technique expands access to oxygen-isotope measurements of iron oxides, thereby enhancing their utility in Earth and environmental sciences.","PeriodicalId":27,"journal":{"name":"Analytical Chemistry","volume":"7 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-28DOI: 10.1021/acs.analchem.5c01132
Li-Bang Zhu, Shou-Nian Ding
Conventional electrochemiluminescence (ECL) systems typically rely on coreactants, such as hydrogen peroxide or dissolved oxygen, to generate reactive oxygen species (ROS), which are essential for effective light emission. However, these coreactants are inherently limited by self-decomposition and solubility constraints, which can hinder the detection accuracy and light emission efficiency of ECL systems. In this work, we propose an innovative method that eliminates the need for coreactants by utilizing inverse opal TiO2 (IO-TiO2) coupled with upconversion nanoparticles (UCNPs) as a coreaction accelerator. By harnessing near-infrared (NIR) irradiation, UCNPs efficiently convert this light into ultraviolet (UV) light, stimulating IO-TiO2 to generate ROS through water oxidation. The generated ROS subsequently reacts with luminol anion radicals, producing robust ECL emission while eliminating interference from luminescence caused by coreactants. Electron paramagnetic resonance (EPR) results confirm the generation of hydroxyl (•OH), singlet oxygen (1O2), and superoxide anion radicals (O2•–) during the electrochemical water oxidation process, which ensured the feasibility of the experimental approach. To demonstrate the practical application of this method, human chorionic gonadotropin (HCG) was selected as a model analyte. This proposed ECL immunoassay exhibited high sensitivity and stability in detecting HCG, with a linear range of 4 pg/mL to 1 μg/mL and a low limit of detection (LoD) of 1.33 pg/mL (S/N = 3). This breakthrough offers a promising avenue for developing ECL systems that are more sensitive, efficient, and highly versatile, expanding the range of applications in bioanalysis and environmental monitoring.
{"title":"Coreactant-free Electrochemiluminescence: ROS Generation via Upconversion Nanoparticles-Sensitized Inverse Opal TiO2 Photocatalysis under NIR Irradiation","authors":"Li-Bang Zhu, Shou-Nian Ding","doi":"10.1021/acs.analchem.5c01132","DOIUrl":"https://doi.org/10.1021/acs.analchem.5c01132","url":null,"abstract":"Conventional electrochemiluminescence (ECL) systems typically rely on coreactants, such as hydrogen peroxide or dissolved oxygen, to generate reactive oxygen species (ROS), which are essential for effective light emission. However, these coreactants are inherently limited by self-decomposition and solubility constraints, which can hinder the detection accuracy and light emission efficiency of ECL systems. In this work, we propose an innovative method that eliminates the need for coreactants by utilizing inverse opal TiO<sub>2</sub> (IO-TiO<sub>2</sub>) coupled with upconversion nanoparticles (UCNPs) as a coreaction accelerator. By harnessing near-infrared (NIR) irradiation, UCNPs efficiently convert this light into ultraviolet (UV) light, stimulating IO-TiO<sub>2</sub> to generate ROS through water oxidation. The generated ROS subsequently reacts with luminol anion radicals, producing robust ECL emission while eliminating interference from luminescence caused by coreactants. Electron paramagnetic resonance (EPR) results confirm the generation of hydroxyl (•OH), singlet oxygen (<sup>1</sup>O<sub>2</sub>), and superoxide anion radicals (O<sub>2</sub><sup>•–</sup>) during the electrochemical water oxidation process, which ensured the feasibility of the experimental approach. To demonstrate the practical application of this method, human chorionic gonadotropin (HCG) was selected as a model analyte. This proposed ECL immunoassay exhibited high sensitivity and stability in detecting HCG, with a linear range of 4 pg/mL to 1 μg/mL and a low limit of detection (LoD) of 1.33 pg/mL (<i>S</i>/<i>N</i> = 3). This breakthrough offers a promising avenue for developing ECL systems that are more sensitive, efficient, and highly versatile, expanding the range of applications in bioanalysis and environmental monitoring.","PeriodicalId":27,"journal":{"name":"Analytical Chemistry","volume":"30 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It might be intriguing to explore the tailored ability of a bihairpin-structured molecular beacon (bhMB) for improving reaction kinetics and assay sensitivity for a label-free ratiometric fluorescence assay of a specific trigger (T*), in which red and green silver nanoclusters (rSNC and gSNC) were utilized as two reverse emitting reporters. Unlike traditional dually labeled MB, herein the proposed bhMB was designed with two hairpin subunits for specific recognition and signaling readout. Four functional modules were included: the complement of T* in the identifiable hairpin, the template sequence of rSNC and gSNC in the signaling hairpin, two variable consensus loops capable of complementarily hybridizing to form one paired stem, and two stems able to merge into one new loop. Upon introducing T*, the conformation switch of bhMB was triggered via affinity linking to a cognate consensus sequence, thereby reconstructing a perfect stem–loop monohairpin structure. As such, the mutual transition of loops and stems between nonbinding and binding states was powered by a population-shift mechanism to shift the thermodynamic equilibrium toward the binding state. Benefiting from the structure confinement of bhMB, the local concentration of reactive species was increased to speed up the reaction kinetics. In a tailored response route, the template sequence for rSNC clustering was merged with increased red fluorescence, while the emission of gSNC was decreased, pointing to the obtained specific and sensitive ratiometric signal via built-in correction. Thus, this label-free strategy would be the first example to integrate recognizing and signaling subunits in a double-hairpin beacon for label-free biosensing and potential applications.
{"title":"Target-Responsive Conformation Switch of Bihairpin Molecular Beacon to Illustrate Ratiometric Fluorescence Biosensing of Dual-Emissive Silver Nanoclusters","authors":"Zhihan Zhang, Yuqing Zhang, Chunli Yang, Jiayang He, Xinyue Jia, Min Long, Ruo Yuan, Wenju Xu","doi":"10.1021/acs.analchem.5c00202","DOIUrl":"https://doi.org/10.1021/acs.analchem.5c00202","url":null,"abstract":"It might be intriguing to explore the tailored ability of a bihairpin-structured molecular beacon (<i>bh</i>MB) for improving reaction kinetics and assay sensitivity for a label-free ratiometric fluorescence assay of a specific trigger (<i><b>T</b></i>*), in which red and green silver nanoclusters (<i>r</i>SNC and <i>g</i>SNC) were utilized as two reverse emitting reporters. Unlike traditional dually labeled MB, herein the proposed <i>bh</i>MB was designed with two hairpin subunits for specific recognition and signaling readout. Four functional modules were included: the complement of <i><b>T</b></i>* in the identifiable hairpin, the template sequence of <i>r</i>SNC and <i>g</i>SNC in the signaling hairpin, two variable consensus loops capable of complementarily hybridizing to form one paired stem, and two stems able to merge into one new loop. Upon introducing <i><b>T</b></i>*, the conformation switch of <i>bh</i>MB was triggered via affinity linking to a cognate consensus sequence, thereby reconstructing a perfect stem–loop monohairpin structure. As such, the mutual transition of loops and stems between nonbinding and binding states was powered by a population-shift mechanism to shift the thermodynamic equilibrium toward the binding state. Benefiting from the structure confinement of <i>bh</i>MB, the local concentration of reactive species was increased to speed up the reaction kinetics. In a tailored response route, the template sequence for <i>r</i>SNC clustering was merged with increased red fluorescence, while the emission of <i>g</i>SNC was decreased, pointing to the obtained specific and sensitive ratiometric signal via built-in correction. Thus, this label-free strategy would be the first example to integrate recognizing and signaling subunits in a double-hairpin beacon for label-free biosensing and potential applications.","PeriodicalId":27,"journal":{"name":"Analytical Chemistry","volume":"36 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-28DOI: 10.1021/acs.analchem.4c03466
Alberto Marchetto, Monica Tirapelle, Luca Mazzei, Eva Sorensen, Maximilian O. Besenhard
High-performance liquid chromatography (HPLC) remains the gold standard for analyzing and purifying molecular components in solutions. However, developing HPLC methods is material- and time-consuming, so computer-aided shortcuts are highly desirable. In line with the digitalization of process development and the growth of HPLC databases, we propose a data-driven methodology to predict molecule retention factors as a function of mobile phase composition without the need for any new experiments, solely relying on molecular descriptors (MDs) obtained via simplified molecular input line entry system (SMILES) string representations of molecules. This new approach combines: (a) quantitative structure–property relationships (QSPR) using MDs to predict solute-dependent parameters in (b) linear solvation energy relationships (LSER) and (c) linear solvent strength (LSS) theory. We demonstrate the potential of this computational methodology using experimental data for retention factors of small molecules made available by the research community for which the MDs were obtained via SMILES string representations determined by the structural formulas of the molecules. This method can be adopted directly to predict elution times of molecular components; however, in combination with first-principle-based mechanistic transport models, the method can also be employed to optimize HPLC methods in-silico. Both options can reduce the experimental load and accelerate HPLC method development significantly, lowering the time and cost of the drug manufacturing cycle and reducing the time to market. Given the growing number and quality of HPLC databases, the predictive power of this methodology will only increase in the coming years.
{"title":"In Silico High-Performance Liquid Chromatography Method Development via Machine Learning","authors":"Alberto Marchetto, Monica Tirapelle, Luca Mazzei, Eva Sorensen, Maximilian O. Besenhard","doi":"10.1021/acs.analchem.4c03466","DOIUrl":"https://doi.org/10.1021/acs.analchem.4c03466","url":null,"abstract":"High-performance liquid chromatography (HPLC) remains the gold standard for analyzing and purifying molecular components in solutions. However, developing HPLC methods is material- and time-consuming, so computer-aided shortcuts are highly desirable. In line with the digitalization of process development and the growth of HPLC databases, we propose a data-driven methodology to predict molecule retention factors as a function of mobile phase composition without the need for any new experiments, solely relying on molecular descriptors (MDs) obtained via simplified molecular input line entry system (SMILES) string representations of molecules. This new approach combines: (a) quantitative structure–property relationships (QSPR) using MDs to predict solute-dependent parameters in (b) linear solvation energy relationships (LSER) and (c) linear solvent strength (LSS) theory. We demonstrate the potential of this computational methodology using experimental data for retention factors of small molecules made available by the research community for which the MDs were obtained via SMILES string representations determined by the structural formulas of the molecules. This method can be adopted directly to predict elution times of molecular components; however, in combination with first-principle-based mechanistic transport models, the method can also be employed to optimize HPLC methods in-silico. Both options can reduce the experimental load and accelerate HPLC method development significantly, lowering the time and cost of the drug manufacturing cycle and reducing the time to market. Given the growing number and quality of HPLC databases, the predictive power of this methodology will only increase in the coming years.","PeriodicalId":27,"journal":{"name":"Analytical Chemistry","volume":"33 1","pages":""},"PeriodicalIF":7.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143723847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：