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VALIDATED SPECTROPHOTOMETRIC METHOD FOR THE ESTIMATION OF VINCRISTINE AND VINBLASTINE
摘要： Objective: A simple, sensitive, precise, reproducible and validated UV spectrophotometric methods have been developed for the determination of vincristine (VCR) and vinblastine (VLB) in the pure and dosage forms. Methods: The method was founded on the simple solubility of VCR and VLB in purified water, and their characteristic maximum absorption λ (max) at 295 nm and λ (max) at 268 nm for VCR and VLB respectively in the UV regions. The nature of obedience, to the Bouguer-Lambert-Beer’s law by the VCR and VLB in the range of concentration 5-50 μg/ml was employed to this method. Results: Accuracy and reproducibility of the proposed method were statistically validated by recovery studies. The accuracy of the method for the VCR and VLB was ~ 100.4 % and ~ 100.32 % respectively with good reproducibility. The analytical curves were linear over a wide concentration range (5-50 μg/ml), with a correlation coefficient (r)-0.9998, and 0.9999 for VCR and VLB in that order. The method was showed sufficient precision, with a relative standard deviation (RSD) less than 1%. Conclusion: The method was validated in accordance with Russian general pharmacopoeia article (RGPA) 42-0113-09 and ICH guidelines. Validated method can easily apply for fast, precise and reliable rapid assessment of drug forms and pure substances in the laboratory.
关键词： Vincristine,Quantity determination,Analytical curve,Vinblastine,UV-visible spectrometry
更新于2025-09-23 15:22:29
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - MEMS ion source for ion mobility spectrometry
摘要： This paper describes a miniature, silicon-glass, electron-impact ion source, in which a field emission cathode is separated from the external atmosphere by a vacuum semi-transparent Si3N4 membrane. High necessary for the proper operation of the ion source is generated on chip by an integrated micropump.
关键词： electron-transparent membranes,micropump,field emission electron source,ion source,ion mobility spectrometry
更新于2025-09-23 15:21:21
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Li Permeability Increase in Nano-Sized Amorphous Silicon Layers
摘要： Li permeation through nano-sized amorphous Si layers is investigated for temperatures up to 500°C (773 K) as a function of layer thickness between 12 and 95 nm. For the experiments the Si layers are embedded between 6Li and 7Li isotope enriched oxide based Li reservoirs and the thermally induced isotope exchange (through silicon layers and interfaces) is analyzed by Secondary Ion Mass Spectrometry in order to calculate Li permeabilities. The experiments reveal that the interface between silicon and the Li metal oxide does not hinder Li permeation and Li diffusion in silicon controls the overall process. The determined Li permeability increases drastically by orders of magnitude with decreasing silicon layer thickness, accompanied by a decrease in the activation enthalpy of Li permeation. These results can be explained by a gradual transition of trap-limited slow Li diffusion at high silicon thicknesses to interstitial fast Li diffusion at low Si thicknesses.
关键词： Li permeation,nano-sized layers,Li permeability,trap-limited diffusion,amorphous silicon,Secondary Ion Mass Spectrometry,isotope exchange,interstitial diffusion
更新于2025-09-23 15:21:21
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Applicability of a field portable X-ray fluorescence for analyzing elemental concentration of waste samples
摘要： Determining the chemical properties of waste is crucial to ensure the most effective utilization of waste. The standard laboratory measurements can produce accurate results, but analysis is labor- and time-consuming. The variety of elements that field portable X-ray fluorescence spectrometry (FPXRF) can detect from selected waste materials was studied, including how the results compared with those of inductively coupled plasma mass spectrometry (ICP-MS) measurements. The selected materials were fine fraction reject from solid recovered fuel production, fly ash, biowaste, and compost. Based on the results, FPXRF is reported to be best suited for waste samples, such as ash and compost, because of their physical properties, as follows: not too moist, quite small particle size, and not too heterogeneous. The results obtained from FPXRF showed the lowest relative standard deviation for ash material. The analysis of the limits of agreement between FPXRF and ICP-MS showed that FPXRF was mainly suitable for qualitative assessment. Furthermore, regression analysis showed a linear correlation between FPXRF and ICP-MS results for calcium and zinc in the selected materials. Keeping the limitations in mind, FPXRF could be used for qualitative analysis in waste treatment processes, such as first quality control of waste materials.
关键词： Inductively coupled plasma mass spectrometry,Waste,Field portable X-ray fluorescence spectrometry,Elemental analysis
更新于2025-09-23 15:21:01
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Laser Desorption Ionization-Mass Spectrometry of Linear Diphenylenes Encapsulated in Crystalline Sponge
摘要： Three linear diphenylene compounds having one, two, and three double bonds, respectively, were encapsulated in a nano-porous coordination complex called “crystalline sponge” (CS). The presence of these diphenylene compounds in CS was confirmed by single-crystal X-ray structure analysis and NMR spectroscopy. In CS, CH-π and π-π interactions between the pyridyl group of the triazine ligand in the CS framework and the phenyl group of the diphenylene compounds were determined on the basis of the geometrical orientation in the nanopore. After the single-crystal X-ray structure analysis, the same single crystal was subjected to imaging mass spectrometry (IMS). Molecular ion peaks were almost equally detected in all regions of the target plate where the CSs were present and the search for hotspots was no longer necessary. At the same time, ion peaks derived from the triazine ligand and its metal complex, which are components of the CS framework, were clearly observed. CSs have been shown to be one of the effective matrixes for laser desorption ionization of trace linear conjugate compounds.
关键词： crystalline sponge,diphenylene compound,imaging mass spectrometry
更新于2025-09-23 15:21:01
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Identification of heavy metal-contaminated Tegillarca granosa using laser-induced breakdown spectroscopy and linear regression for classification
摘要： Tegillarca granosa (T. granosa) is susceptible to heavy metals, which may pose a threat to consumer health. Thus, healthy and polluted T. granosa should be distinguished quickly. This study aimed to rapidly identify heavy metal pollution by using laser-induced breakdown spectrometry (LIBS) coupled with linear regression classification (LRC). Five types of T. granosa were studied, namely, Cd-, Zn-, Pb-contaminated, mixed contaminated, and control samples. Threshold method was applied to extract the significant variables from LIBS spectra. Then, LRC was used to classify the different types of T. granosa. Other classification models and feature selection methods were used for comparison. LRC was the best model, achieving an accuracy of 90.67%. Results indicated that LIBS combined with LRC is effective and feasible for T. granosa heavy metal detection.
关键词： laser-induced breakdown spectrometry,shellfish,linear regression classification,heavy metal
更新于2025-09-23 15:21:01
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Low temperature platinum chemical vapor deposition on functionalized self-assembled monolayers
摘要： The reaction pathways of Pt CVD using (COD)PtMe2 – xClx (x = 0, 1, 2) have been investigated on functionalized self-assembled monolayers (SAMs) as models for organic substrates. Residual gas analysis for (COD)PtMe2 and (COD)PtMeCl is consistent with the loss of methyl radicals as the initial step in deposition, while for (COD)PtCl2, the first step is the loss of a chlorine radical. It is further shown using x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry that the deposition process leads to chemical damage of the SAM layer and little Pt deposition. Using this understanding, it is demonstrated that the Pt CVD rate can be controlled using a radical trap. In the presence of 1,4-cyclohexadiene, a well-known alkyl radical trap, Pt deposition was increased by 5× to 10×, creating a room-temperature effective Pt CVD process.
关键词： time-of-flight secondary ion mass spectrometry,x-ray photoelectron spectroscopy,Pt CVD,chemical vapor deposition,self-assembled monolayers,radical trap
更新于2025-09-23 15:21:01
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Comparison of quantitative analyses using SIMS, atom probe tomography, and femtosecond laser ablation inductively coupled plasma mass spectrometry with Si <sub/>1a??X</sub> Ge <sub/>X</sub> and Fe <sub/>1a??X</sub> Ni <sub/>X</sub> binary alloys
摘要： Due to their electrical and physical properties, Si1?XGeX materials are widely used in microelectronic devices. In particular, the Ge component found within Si1?XGeX compounds is important for enhancing carrier mobility and altering the lattice constant of metal-oxide-semiconductor field-effect transistors. In this study, magnetic sector secondary ion mass spectrometry (magnetic sector SIMS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to determine the accurate concentrations of major compositions present within binary alloy samples. However, quantitative SIMS analysis is limited by the matrix effect, which influences the sputter yield of an element in a compound and alters the secondary ionization yields. Quantitative deviations that were due to the matrix effect were reduced by using Cs cluster ions (MCs+ and MCs2+) instead of elemental ions; the SIMS results using the elements were, therefore, compared with those using MCs+ and MCs2+ cluster ions. In the case of Fe1?XNiX alloys that have a less matrix effect compared to Si1?XGeX alloys, both the Cs primary ion beam (Cs+) and an oxygen primary ion beam (O2+) were used to measure the Fe1?XNiX compositions. The quantitative results from the two different primary ion beams were then compared to understand the ionization process. Deviations in the quantitative values gained with the O2+ beam were lower than those obtained using the Cs+ primary ions, meaning that using oxygen as the primary ion improves the accuracy in quantifying Fe1?XNiX compounds. Other reliable tools for analysis such as atom probe tomography and femtosecond laser ablation inductively coupled plasma mass spectrometry were also used in the quantitative analysis, with results that were consistent with the most accurate results obtained using magnetic sector SIMS and ToF-SIMS.
关键词： Si1?XGeX,femtosecond laser ablation inductively coupled plasma mass spectrometry,atom probe tomography,SIMS,Fe1?XNiX,binary alloys
更新于2025-09-23 15:21:01
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EXPRESS: Analysis of Natural Gas Using a Portable Hollow-Core Photonic-Crystal-Coupled Raman Spectrometer
摘要： The low accessibility of natural gas fields and transporting pipelines requires portable online analyzers of the composition of natural gas, ensuring nearly chromatographic precision and capable of in situ analysis of a wide range of gases, including infrared-inactive ones (hydrogen, oxygen, nitrogen, chlorine). We have developed an express method of gas analysis meeting all requirements for the analysis of natural gas and its derivative mixtures using a portable 532 nm Raman spectrometer rigidly connected to a hollow-core crystal photonic fiber.
关键词： hollow-core photonic crystal fiber,HC-PCF,Raman spectrometry,gas chromatography,natural gas,calibration gas mixture
更新于2025-09-23 15:21:01
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Laser-Induced Dissociation of the Monolayer of Adsorbed Methanol Molecules
摘要： Astronomical observations indicate a high abundance of methanol molecules in the gas phase of molecular-cloud dense cores, which cannot be explained by gas-phase chemical reactions only. A significant contribution to the methanol abundance should be provided by chemical reactions on the dust particle surface with subsequent desorption of the produced molecules into the gas phase. For the development and refinement of models involving these processes, laboratory studies of photo-induced processes occurring in the adsorbed material are necessary. In this paper, the experiment results of adsorbed methanol molecules are presented. A methanol molecule monolayer, physically adsorbed on fused silica surface cooled by liquid nitrogen (Т ～ 100 K), was irradiated in high vacuum by nanosecond pulses of an excimer KrF laser with a fixed wavelength λ = 248 nm. The photodissociation products of three-photon laser excitation were recorded by a quadrupole mass spectrometer. Relative yields of photofragments H, OH, and CH3 were determined. Photolysis of partially deuterated CH3OH molecules has shown that hydrogen atoms can be ejected both from hydroxyl and methyl groups. In contrast to the isolated molecule photolysis in the gas phase and dissociation of the multilayer molecular coatings, photoexcitation of adsorbed methanol monolayer even in the energy region of 10 eV does not cause noticeable chemical transformations and does not lead to the formation of molecular components H2 and CH4. Due to existing astrochemical modeling problems, possible application methods of the obtained laboratory results are considered.
关键词： chemical reactions,astronomical observations,adsorbed monolayer,mass spectrometry,photo-induced processes,gas phase,dust particle surface,KrF laser,photodissociation,methanol
更新于2025-09-23 15:21:01