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Matrix-Assisted Laser Desorption/Ionization Time-of-Flight
摘要： Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has undoubtedly changed the way clinical microbiology laboratories (CMLs) diagnose infectious diseases. Now commonly used for the routine identification of cultured bacteria and yeast, CMLs are looking to expand the use of MALDI-TOF MS to other areas of infectious diseases diagnostics. The relative ease of performance, low cost per test, and rapidity of results has prompted the development of advanced techniques, such as antimicrobial susceptibility, direct-from-specimen organism identification, and several other techniques that may improve on conventional techniques.
关键词： MALDI-TOF MS,Phenotypic susceptibility testing,Rapid organism identification,Infectious diseases diagnostics
更新于2025-09-11 14:15:04
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Polycarboxyl metal–organic framework UiO-66-(COOH)2 as efficient desorption/ionization matrix of laser desorption/ionization mass spectrometry for selective enrichment and detection of phosphopeptides
摘要： Specific enrichment and efficient detection of phosphopeptides are important for phosphoproteomic analysis. Metal–organic frameworks (MOFs) have been proved to be effective enrichment materials combined with the analysis of mass spectrometry. In this work, we have developed a polycarboxylic group MOF-UiO-66-(COOH)2 used as both efficient enrichment material for phosphopeptides and efficient desorption/ionization matrix of laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF MS) without elution. The crystal is spherical and the particle size is about 200 nm. When using it as enrichment material and MS matrix, phosphopeptides of β-casein can be efficiently detected under superior low detection limits of 1 fmol μL?1, and at an extremely low molar ratio of phosphoprotein/non-phosphoprotein (1:2000) mixtures, there are still four phosphopeptides that can be observed. When detecting real samples, most phosphopeptides of non-fat milk and human saliva can be observed, which is comparable with the literature.
关键词： Metal–organic frameworks,Nanocomposite,Specific adsorption,Matrix of MALDI-TOF MS
更新于2025-09-11 14:15:04
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Quantitative analysis of progesterone using isotope dilution-matrix-assisted laser desorption ionization-time of flight mass spectrometry as a reference procedure for radioimmunoassay
摘要： Background: Progesterone is one of the female steroid hormones and plays an important role in the menstrual cycle and during pregnancy. It is especially important in preparing the uterus for the implantation of the blastocyst and maintaining pregnancy. The concentration in human serum is measured to determine the ovarian function retroactively and the cause of abortion in early pregnancy. Methods: A quantification assay based on isotope dilution mass spectrometry to determine the concentration of progesterone in human serum is reported. Incorporated with 13C3-progesterone, serum samples were subjected to progesterone extraction and clean-up by C4 solid-phase-extraction columns and hexane-based liquid/liquid extraction, respectively. The cleaned-up serum samples were then subjected to MALDI-TOF mass spectrometry for the quantification of progesterone. Results: Progesterone and the internal standard, 13C3-progesterone, were measured in the selected reaction monitoring mode for the transitions m/z 315.4 to 108.9 and m/z 318.4 to 111.9, respectively. We calculated the peak area ratio of progesterone to 13C3-progesterone in the mass spectrometry. The progesterone concentration in human serum was calculated by substituting the peak area ratio into an isotope dilution calibration curve, and then compared with the radioimmunoassay. Conclusions: In the study, the concentrations of serum progesterone were measured, and the recovered progesterone concentration determined by the assay showed good robustness and consistency in comparison to the conventional radioimmunologic assay. We concluded that the 13C3-progesterone-based quantification assay is a robust method for the measurement of serum progesterone.
关键词： isotope dilution,radioimmunologic assay,MALDI-TOF/MS,progesterone
更新于2025-09-11 14:15:04
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Aptamer-gold nanoparticle doped covalent organic framework followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for selective enrichment and detection of human insulin
摘要： In this work, we introduced an aptamer modified Au nanoparticles doped covalent organic frameworks composite (IBAs-AuNPs/COF) to improve the property of selective enrichment of insulin from serum samples. The Au nanoparticles were immobilized on imine-based COF by in-situ reduction reaction via mussel inspired polydopamine coating, and then sulfhydryl-containing aptamers were bonded to the surface of AuNPs through an Au-S linkage. Due to the excellent adsorption property of COF and specific recognition between insulin and IBAs, the IBAs-AuNPs/COF composites show selective and satisfactory extraction property to insulin in serum samples. Excellent specificity was obtained for insulin in the presence of 50-fold interfering substances including human immunoglobulin, lysozyme and biotin. The concentrations of insulin in the range of 1.0 to 50.0 μg L ?1 show good linear relationship ( R 2 = 0.9917) with limit of detection and limit of quantitation of 0.28 μg L ?1 and 0.93 μg L ?1 , respectively. Then, the IBAs-AuNPs/COF composites were applied to enrich insulin in serum samples followed by analysis with matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS). After the recovery experiment, the developed method shows good recoveries in range of 91.6%–112.4% with low RSD value (2.4%–9.4%, n = 3) for diabetic and healthy serum samples. The developed IBAs-AuNPs/COF composites propose a new perspective for selective and efficient enrichment of biomarkers in serum samples by functionalized COF.
关键词： Composites,Insulin aptamer,Covalent organic frameworks,Serum samples,Biomolecule,MALDI-TOF-MS
更新于2025-09-11 14:15:04
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TOF‐SIMS MS/MS Depth Profiling of OLED Devices for Elucidating the Degradation Process
摘要： Rationale: OLED products based on display applications have become popular in the past 10 years, and new products are being commercialized with rapid frequency. Despite the many advantages of OLEDs, these devices still have a problem concerning lifetime. To gain an understanding of the degradation process, the authors have investigated the molecular information on deteriorated OLED devices using TOF-SIMS. Methods: TOF-SIMS depth profiling is an indispensable way to evaluate OLED devices. However, the depth profiles of OLEDs are generally difficult due to the mass interference among organic compounds, including degradation products. In this study, the MS/MS depth profiling method was used to characterize the OLED devices. Results: After the degradation, the defects which were comprised of small hydrocarbons were observed. Within the defect area, the diffusion of all OLED compounds were also observed. It is supposed that the source of small hydrocarbons derives from decomposition of the OLED compounds and/or contaminant at the ITO interface. Conclusions: The true compound distributions have been discovered by MS/MS depth profiling methods. The results suggest that the luminance decay is mainly due to the decomposition and diffusion of OLED compounds, and that OLED decomposition may be accelerated by adventitious hydrocarbons present at the ITO surface.
关键词： OLEDs,MS/MS Depth profiling,TOF-SIMS,Tandem MS
更新于2025-09-11 14:15:04
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Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Typings of Edible Oils through Spectral Networking of Triacylglycerol Fingerprints
摘要： Adulteration of edible oils by the manufacturers has been found frequently in modern societies. Due to the complexity of the chemical contents in edible oils, it is challenging to quantitatively determine the extent of adulteration and prove the authenticity of edible oils. In this study, a robust and simple MALDI-TOF-MS platform for rapid ?ngerprinting of triacylglycerols (TAGs) in edible oils was developed, where spectral similarity analysis was performed to quantitatively reveal correlations among edible oils in the chemical level. Speci?cally, we proposed oil networking, a spectral similarity-based illustration, which enabled reliable classi?cations of tens of commercial edible oils from vegetable and animal origins. The strategy was superior to traditional multivariate statistics due to its high sensitivity in probing subtle changes in TAG pro?les, as further demonstrated by the success in determination of the adulterated lard in a food fraud in Taiwan. Finally, we showed that the platform allowed quantitative assessment of the binary mixture of olive oil and canola oil, which is a common type of olive oil adulteration in the market. Overall, these results suggested a novel strategy for chemical ?ngerprint-based quality control and authentication of oils in the food industry.
关键词： triacylglycerols,oil networking,spectral similarity,adulteration,MALDI-TOF-MS,edible oils
更新于2025-09-11 14:15:04
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A New Analytical Charge Transfer Model for Time-of-Flight Image Sensors
摘要： A powerful tool for analyzing the performances of an image sensor designed for time-of-flight measurement purposes, the impulse response measurement (IRM), is presented. A way to measure the charges diffusion time (time for the photogenerated charges to be collected by the photodiode) using the analysis of an IRM is given. An unexpected phenomenon that occurs when performing a specific IRM is then showcased: performing two successive transfers, a short duration one followed by a long duration one is actually less efficient than performing a single transfer of long duration (same duration as the second transfer in the first case). Accordingly, a mathematical sufficient condition on the charge transfer efficiency function (CTEF) is enounced. A physical modeling based on thermionic emission theory and the influence of the potential barrier’s width on its effective height is presented. The model leads to a new CTEF expression that fulfills the mathematical requirement. Finally, a numerical simulation with the new CTEF fitting the experimental IRM data is performed.
关键词： time-of-flight (TOF),thermionic emission theory,Dirac-light pulse (DLP),diffusion time,impulse response measurement (IRM),Charge transfer efficiency function (CTEF),CMOS image sensor (CIS),light image detection and ranging (LIDAR),sense node (SN)
更新于2025-09-10 09:29:36
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Two-dimensional TiO2 Nanoflakes Enable Rapid SALDI-TOF-MS Detection of Toxic Small Molecules (dyes and their metabolites) in Complex Environments
摘要： High surface area (136 m2·g-1) nanoporous two-dimensional TiO2 nanoflakes are applied as an adsorbent and meanwhile a matrix for toxic small molecule analysis using positive-ion surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOF MS). The TiO2 nanoflakes enable one-step enrichment and analysis, greatly simplifying the analysis technique. Due to the high enrichment efficiency and low background noise, small molecule organic contaminants at ppt or even sub-ppt concentrations such as malachite green (10 pg/mL), leucomalachite green (10 pg/mL), cetyltrimethylammonium bromide (0.001 pg/mL), rhodamine B (0.001 pg/mL), and crystal violet (0.1 pg/mL) were detected. In addition, malachite green and its metabolite leucomalachite green at ng/mL concentrations were successfully detected from fish blood and fish extracts, and crystal violet and its homologues at ng/cm2 concentrations were detected from inks on thermal receipt papers obtained from local supermarket.
关键词： small molecules,nanoflakes,toxic,TiO2,SALDI-TOF-MS
更新于2025-09-10 09:29:36
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Fabrication of a Bilayer Structure of Cu and Polyimide to Realize Circuit Microminiaturization and High Interfacial Adhesion in Flexible Electronic Devices
摘要： With commercialization of the 5th generation mobile communication system and the further spread of the Internet of Things, industrial innovation is arriving with new business fields related to concepts such as high-speed communication, self-driving vehicles, and remote medicine. One of the challenges is the realization of flexible devices with high-definition circuits, which requires new fabrication techniques for Cu films on polymer substrates to meet demands and an understanding of the Cu/polymer interfacial nanostructure to assure product quality. We have developed a promising technique for the fabrication of Cu film on polyimide (PI), which consists mainly of very simple semiconductor device processes. This technique allows for control of the Cu thickness with nanometer precision to form miniaturized Cu circuits with potential advantages in terms of interfacial adhesion and material/production costs. The Cu/PI interfaces fabricated by conventional vapor deposition and the new technique are systematically analyzed using synchrotron hard-X-ray photoelectron spectroscopy (HAXPES), scanning transmission electron microscopy (STEM), and time-of-flight secondary ion mass spectroscopy (TOF-SIMS). With conventional vapor deposition, it was discovered that evaporated Cu atoms decompose the PI and an oxidation layer with a thickness of several nanometers that deteriorates the interfacial adhesion could be visualized at the Cu/PI interface. With the new technique, the decomposition of PI and interfacial oxidation are significantly suppressed. Furthermore, the proposed technique can be broadly applied to the investigation of metal/polymer interfaces fabricated by polymer coating on a metal substrate, which has so far been impossible.
关键词： STEM,TOF-SIMS,Flexible printed circuits,Microminiaturization,Interfacial adhesion,HAXPES,Flexible electronics
更新于2025-09-10 09:29:36
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Pre-Processing MALDI/TOF Mass Spectra by Using Geena 2
摘要： Geena 2 is a tool for filtering, averaging, and aligning MALDI/TOF mass spectra, designed to assist scientists in the analysis of high volumes of data and support them for comparative studies. Three web interfaces are available with different levels of complexity. In this manuscript, we explain how to use Geena 2 with these three interfaces to perform analyses of one’s own data. Two support protocols showing how to check the example input file and how to create an input file with own data are also presented.
关键词： spectra alignment,mass spectrometry,pre-processing,MALDI/TOF
更新于2025-09-09 09:28:46