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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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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