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Superior photocatalytic activity of tungsten disulfide nanostructures: role of morphology and defects
摘要： Tungsten disulphide (WS2) nanostructures, WS2 nanosheets (WNS) and WS2 nanorods (WNR), were synthesized by varying the surfactant, N-cetyl-N,N,N-trimethyl ammonium bromide (CTAB), concentration using facile hydrothermal technique. Samples were characterized by high-resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM) for morphology, X-ray diffraction (XRD) to confirm their phase and crystal structure, photoluminescence (PL) and Raman studies for the determination of defect density, Tauc plot for the determination of band gap, Fourier transform infra red (FTIR) spectroscopy for functional groups and bonds, and Brunauer–Emmett–Teller (BET) isotherms for the determination of pore size and surface area. A comparative study using WS2 nanostructures (WNS and WNR) was conducted to observe the photocatalytic degradation efficiency (?) and degradation kinetics on methylene blue (MB) and 4-chlorophenol (4-CP). The superior photocatalytic performance of WNS over WNR is attributed to enhanced pore size and reduced defect density. High-performance liquid chromatography was carried out for the determination of intermediate products during photocatalytic degradation.
关键词： Raman,High-performance liquid chromatography,WS2 nanostructures,Photoluminescence,Photocatalysis
更新于2025-09-23 15:23:52
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High-Performance Chromatographic Characterization of Surface Chemical Heterogeneities of Fluorescent Organic–Inorganic Hybrid Core–Shell Silica Nanoparticles
摘要： In contrast to small-molar-mass compounds, detailed structural investigations of inorganic core–organic ligand shell hybrid nanoparticles remain challenging. The assessment of batch-reaction-induced heterogeneities of surface chemical properties and their correlation with particle size has been a particularly long-standing issue. Applying a combination of high-performance liquid chromatography (HPLC) and gel permeation chromatography (GPC) to ultra-small (<10 nm diameter) poly(ethylene glycol)-coated (PEGylated) fluorescent core–shell silica nanoparticles, we elucidate here previously unknown surface heterogeneities resulting from varying dye conjugation to nanoparticle silica cores and surfaces. Heterogeneities are predominantly governed by dye charge, as corroborated by molecular dynamics simulations. We demonstrate that this insight enables the development of synthesis protocols to achieve PEGylated and targeting ligand-functionalized PEGylated silica nanoparticles with dramatically improved surface chemical homogeneity, as evidenced by single-peak HPLC chromatograms. Because surface chemical properties are key to all nanoparticle interactions, we expect these methods and fundamental insights to become relevant to a number of systems for applications, including bioimaging and nanomedicine.
关键词： surface chemistry heterogeneity,high-performance liquid chromatography,nanoparticle characterization,nanoparticle surface functionalization,fluorescence correlation spectroscopy,molecular dynamics,nanoparticle heterogeneity
更新于2025-09-23 15:23:52
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Green method by diffuse reflectance infrared spectroscopy and spectral region selection for the quantification of sulphamethoxazole and trimethoprim in pharmaceutical formulations
摘要： An alternative method for the quantification of sulphametoxazole (SMZ) and trimethoprim (TMP) using diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) and partial least square regression (PLS) was developed. Interval Partial Least Square (iPLS) and Synergy Partial Least Square (siPLS) were applied to select a spectral range that provided the lowest prediction error in comparison to the full-spectrum model. Fifteen commercial tablet formulations and forty-nine synthetic samples were used. The ranges of concentration considered were 400 to 900 mg g-1 SMZ and 80 to 240 mg g-1 TMP. Spectral data were recorded between 600 and 4000 cm-1 with a 4 cm-1 resolution by Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The proposed procedure was compared to high performance liquid chromatography (HPLC). The results obtained from the root mean square error of prediction (RMSEP), during the validation of the models for samples of sulphamethoxazole (SMZ) and trimethoprim (TMP) using siPLS, demonstrate that this approach is a valid technique for use in quantitative analysis of pharmaceutical formulations. The selected interval algorithm allowed building regression models with minor errors when compared to the full spectrum PLS model. A RMSEP of 13.03 mg g-1 for SMZ and 4.88 mg g-1 for TMP was obtained after the selection the best spectral regions by siPLS.
关键词： green analytical method,diffuse reflectance infrared Fourier transform spectroscopy,interval partial least squares (iPLS),chemometrics,synergy partial least squares (siPLS),high performance liquid chromatography
更新于2025-09-23 15:22:29
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Simple, Rapid, and Sensitive Determination of Thiols by Liquid Chromatography with Fluorescence Detection
摘要： Thiol compounds are important for protecting cells from oxidative stress. One common method of quantifying thiols is liquid chromatographic separation with fluorescence detection of their derivatives. The pH and the concentration of tris (2-carboxyethyl) phosphine hydrochloride in the reaction medium were shown to have significant effects on the fluorescence intensity of five thiol compounds: cysteine, glutathione, and three phytochelatins. The optimal pH range for derivatization, as indicated by the maximum fluorescence intensities, was 7.75–8.0 for all of the evaluated thiols. The thiol derivative fluorescence increased and then decreased with the tris (2-carboxyethyl) phosphine hydrochloride concentration. In particular, the fluorescence intensities of all of the derivatives decreased by 96.5–99.9% when tris (2-carboxyethyl) phosphine hydrochloride levels were increased from 0.1 to 1 mmol L?1. We attributed these changes to preferential interactions between tris (2-carboxyethyl) phosphine hydrochloride and the thiol-specific fluorophore, monobromobimane. We describe herein a method, based on our optimized solution pH and tris (2-carboxyethyl) phosphine hydrochloride concentration, that is rapid (12 min) and boasts excellent recovery (91.3–102%), sensitivity (limit of detections, 17.8–75.2 pmol L?1) and precision (relative standard deviation values ≤1.03%) for the quantification of these thiol compounds in microalgal samples.
关键词： tris (2-carboxyethyl) phosphine hydrochloride,High-performance liquid chromatography (HPLC),thiol compounds,monobromobimane
更新于2025-09-23 15:22:29
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Cost effective synthesis of p-type Zn-doped MgAgSb by planetary ball-milling with enhanced thermoelectric properties
摘要： A melamine-based porous organic polymer (mPMF) was synthesized as solid phase extraction (SPE) adsorbent for inline SPE-high performance liquid chromatography (HPLC)-ultraviolet detector (UV) analysis of five phytohormones. Melamine contributed to the rich π-electron and N-containing triazine structure for mPMF, which could form π-π interaction and intermolecular hydrogen bond with -COOH containing phytohormones. The synthesized mPMF adsorbent shows extremely high extraction efficiency for five target analytes (>80%) including salicylic acid, indole-3-acetic acid, abscisic acid, 2,4-dichlorophenoxyacetic acid and 1-naphthalene acetic acid. The factors affecting extraction of the target phytohormones were investigated and the optimized experimental conditions were established. The linear range was 0.2–100 μg/L for five target phytohormones. The developed method of mPMF-inline-SPE-HPLC-UV was applied for the analysis of trace target phytohormones in tomato and grape juice samples, and the recovery in the range of 83.1–116% and 87.2–121% was obtained for the spiked tomato and grape juice, respectively. This method has the advantages of high sensitivity and good reproducibility, and it has good application potential for the analysis of phytohormones in fruit samples. Moreover, inline analysis avoided the problems of sample pollution and sample loss, and provided a sample throughput of 5/h.
关键词： Phytohormones,Porous organic polymer,Fruit juice,Inline solid phase extraction,High performance liquid chromatography
更新于2025-09-19 17:15:36
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Red‐Blood‐Cell Waveguide as a Living Biosensor and Micromotor
摘要： The changes of flavor components during boiling in Lentinus edodes were studied by high-performance liquid chromatography and gas chromatography-mass spectrometry in this article. Results showed that nonvolatile flavor components in L. edodes gradually transferred into the soup during boiling. Contents of nonvolatile flavor substances in the soup increased significantly (p < .05) compared with the preboiling period (15 minutes) and gradually maintained a balanced situation with the boiling time extended. During boiling, content of alcohols gradually reduced, especially the content of 1-octen-3-ol, which is a typical flavor component in L. edoedes. The contents of sulfur compounds, aldehydes, and hydrocarbons increased first and finally decreased gradually with the boiling time extended. Therefore, the changes of flavor components in the soup almost maintained a balanced situation with the boiling time from 30 to 60 minutes. The results of this article could provide a theoretical basis for the changes of flavor compounds in L. edodes during boiling.
关键词： flavor components,gas chromatography–mass spectrometry,High-performance liquid chromatography,boiling,Lentinus edodes
更新于2025-09-11 14:15:04
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Controlling Surface Chemical Heterogeneities of Ultrasmall Fluorescent Core–Shell Silica Nanoparticles as Revealed by High-Performance Liquid Chromatography
摘要： Ultrasmall (diameter below 10 nm) fluorescent core?shell silica nanoparticles have garnered increasing attention in recent years as a result of their high brightness and favorable biodistribution properties important for applications including bioimaging and nanomedicine. Here, we present an in-depth study that provides new insights into the physical parameters that govern full covalent fluorescent dye encapsulation within the silica core of poly(ethylene glycol)-coated core?shell silica nanoparticles referred to as Cornell prime dots (C′ dots). We use a combination of high-performance liquid chromatography (HPLC), gel-permeation chromatography, and fluorescence correlation spectroscopy to monitor the result of ammonia concentration in the synthesis of C′ dots from negatively and positively charged versions of near-infrared dyes Cy5 and Cy5.5. HPLC, in particular, allows the distinction between cases of full versus partial dye encapsulation in the silica particle core leading to surface chemical heterogeneities in the form of hydrophobic surface patches, which, in turn, modulate biological response in ferroptotic cell death experiments. Our results demonstrate that there is a complex interplay between dye?dye and dye?silica cluster interactions originally formed in the sol?gel synthesis governing optimal dye encapsulation. We expect that the reduced surface chemical heterogeneities will make the resulting nanoparticles attractive for a number of applications in biology and medicine.
关键词： gel-permeation chromatography,ferroptotic cell death,high-performance liquid chromatography,fluorescent core?shell silica nanoparticles,fluorescence correlation spectroscopy
更新于2025-09-11 14:15:04
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7.3: Research on LCD display performance improvement based on mini‐LED backlight
摘要： The changes of flavor components during boiling in Lentinus edodes were studied by high-performance liquid chromatography and gas chromatography-mass spectrometry in this article. Results showed that nonvolatile flavor components in L. edodes gradually transferred into the soup during boiling. Contents of nonvolatile flavor substances in the soup increased significantly (p < .05) compared with the preboiling period (15 minutes) and gradually maintained a balanced situation with the boiling time extended. During boiling, content of alcohols gradually reduced, especially the content of 1-octen-3-ol, which is a typical flavor component in L. edoedes. The contents of sulfur compounds, aldehydes, and hydrocarbons increased first and finally decreased gradually with the boiling time extended. Therefore, the changes of flavor components in the soup almost maintained a balanced situation with the boiling time from 30 to 60 minutes. The results of this article could provide a theoretical basis for the changes of flavor compounds in L. edodes during boiling.
关键词： flavor components,gas chromatography–mass spectrometry,High-performance liquid chromatography,boiling,Lentinus edodes
更新于2025-09-11 14:15:04
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Enhanced Synergetic Catalytic Effect of Mo <sub/>2</sub> C/NCNTs@Co Heterostructures in Dye-Sensitized Solar Cells: Fine-Tuned Energy Level Alignment and Efficient Charge Transfer Behavior
摘要： This study proposed a new ballpoint connector-protected salt-oil-salt liquid phase microextraction for extraction and enrichment of trace rhein and chrysophanol in rhubarb prior to determination of the analytes by high performance liquid chromatography. In this study, a handy ballpoint connector (between ballpoint tip and ink chamber) was used as extraction device, in which its cavity was filled with n-octanol, and the bare n-octanol in its two opening ends was covered with a thin layer of sodium chloride film. The design subtly assembled salt film onto ballpoint connector for extraction and enrichment, which greatly improved the enrichment factors of the target analytes. Moreover, the novel procedure and its extraction mechanism were described and analyzed, and several crucial parameters reflecting the extraction effect were investigated and optimized. Under optimum conditions, high enrichment factors (247 and 127), good linearities with r ≥ 0.9998, limits of detection (0.6–1.1 ng/mL), relative standard deviations of intra- and interday (2.2–8.8% and 4.3–8.9%), and average recoveries (97.6–98.1%), were obtained, respectively. The proposed method can not only eliminate the negative effects from viscosity and ion strength at high salt concentration of sample phase, but also make salting-out effect be focused on small area so as to maximize the extraction effect.
关键词： high-performance liquid chromatography,rhubarb,liquid-phase microextraction,ballpoint connector,Traditional Chinese medicine
更新于2025-09-11 14:15:04
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High-performance liquid chromatography analysis of salivary bisphenol A levels from light-cured and chemically cured orthodontic adhesives
摘要： Our objective was to assess the levels of bisphenol A (BPA) released from light-cured and chemically cured resins used for orthodontic bracket bonding in 1 month. Methods: Saliva specimens were obtained at 5 time periods from 40 healthy patients treated with orthodontic mechanotherapeutics. The periods of collections were just before bonding orthodontic brackets, followed by 30 minutes, 1 day, 1 week, and 1 month after orthodontic bonding. The specimens were analyzed with the high-performance liquid chromatography/mass spectrometry method for quantitative evaluation of BPA levels. Results: We observed a large increase in BPA levels 30 minutes after orthodontic bonding in the 2 groups. Thereafter, there was sudden decline in BPA levels as time passed, and the levels reached a statistically signi?cant level at 1 month after orthodontic bonding. Interestingly, the amount of BPA released from chemically cured resin was much higher; this was also signi?cant statistically compared with light-cured resins. Conclusions: The results of this in-vivo approach with high-performance liquid chromatography on salivary specimens con?rmed continued release of BPA after bonding brackets for 1 month, although in smaller quantities. The release during the initial 30 minutes is high, making it essential to introduce measures to dilute it for better patient safety.
关键词： orthodontic adhesives,high-performance liquid chromatography,salivary analysis,bisphenol A
更新于2025-09-10 09:29:36