共查询到20条相似文献,搜索用时 11 毫秒
1.
Yanes O Aviles FX Roepstorff P Jørgensen TJ 《Journal of the American Society for Mass Spectrometry》2007,18(2):359-367
The difficulties to detect intact noncovalent complexes involving proteins and peptides by MALDI-TOF mass spectrometry have hindered a widespread use of this approach. Recently, "intensity fading MS" has been presented as an alternative strategy to detect noncovalent interactions in solution, in which a reduction in the relative signal intensity of low molecular mass binding partners (i.e., protease inhibitors) can be observed when their target protein (i.e., protease) is added to the sample. Here we have performed a systematic study to explore how various experimental conditions affect the intensity fading phenomenon, as well as a comparison with the strategy based on the direct detection of intact complexes by MALDI MS. For this purpose, the study is focused on two different protease-inhibitor complexes naturally occurring in solution, together with a heterogeneous mixture of nonbinding molecules derived from a biological extract, to examine the specificity of the approach, i.e., those of carboxypeptidase A (CPA) bound to potato carboxypeptidase inhibitor (PCI) and of trypsin bound to bovine pancreatic trypsin inhibitor (BPTI). Our results show that the intensity fading phenomenon occurs when the binding assay is carried out in the sub-muM range and the interacting partners are present in complex mixtures of nonbinding compounds. Thus, at these experimental conditions, the specific inhibitor-protease interaction causes a selective reduction in the relative abundance of the inhibitor. Interestingly, we could not detect any gaseous noncovalent inhibitor-protease ions at these conditions, presumably due to the lower high-mass sensitivity of MCP detectors. 相似文献
2.
A simple and sensitive method for the determination of patulin in fruit juice and dried fruit samples was developed using a fully automated method consisting of in-tube solid-phase microextraction (SPME) coupled with liquid chromatography–mass spectrometry (LC–MS). Patulin was separated within 5 min by high-performance liquid chromatography using a Synergi MAX-RP 80A column and water/acetonitrile (80/20, v/v) as the mobile phase. Electrospray ionization conditions in the negative ion mode were optimized for MS detection of patulin. The pseudo-molecular ion [M−H]− was used to detect patulin in selected ion monitoring (SIM) mode. The optimum in-tube SPME conditions were 25 draw/eject cycles of 40 μL of sample using a Carboxen 1006 PLOT capillary column as an extraction device. The extracted patulin was readily desorbed from the capillary by passage of the mobile phase, and no carry-over was observed. Using the in-tube SPME LC–MS with SIM method, good linearity of the calibration curve (r = 0.9996) was obtained in the concentration range of 0.5–20 ng/mL using 13C3-patulin as an internal standard, and the detection limit (S/N = 3) of patulin was 23.5 pg/mL. The in-tube SPME method showed >83-fold higher sensitivity than the direct injection method (10 μL injection volume). The within-day and between-day precision (relative standard deviations) were below 0.8% and 5.0% (n = 6), respectively. This method was applied successfully for the analysis of fruit juice and dried fruit samples without interference peaks. The recoveries of patulin spiked into apple juice were >92%, and the relative standard deviations were <4.5%. Patulin was detected at ng/mL levels in various commercial apple juice samples. 相似文献
3.
Durga Jha Kaj Blennow Henrik Zetterberg Jeffrey N. Savas Jörg Hanrieder 《Journal of mass spectrometry : JMS》2024,59(3):e5008
Given the complexity of nervous tissues, understanding neurochemical pathophysiology puts high demands on bioanalytical techniques with respect to specificity and sensitivity. Mass spectrometry imaging (MSI) has evolved to become an important, biochemical imaging technology for spatial biology in biological and translational research. The technique facilitates comprehensive, sensitive elucidation of the spatial distribution patterns of drugs, lipids, peptides, and small proteins in situ. Matrix-assisted laser desorption ionization (MALDI)-based MSI is the dominating modality due to its broad applicability and fair compromise of selectivity, sensitivity price, throughput, and ease of use. This is particularly relevant for the analysis of spatial lipid patterns, where no other comparable spatial profiling tools are available. Understanding spatial lipid biology in nervous tissue is therefore a key and emerging application area of MSI research. The aim of this review is to give a concise guide through the MSI workflow for lipid imaging in central nervous system (CNS) tissues and essential parameters to consider while developing and optimizing MSI assays. Further, this review provides a broad overview of key developments and applications of MALDI MSI-based spatial neurolipidomics to map lipid dynamics in neuronal structures, ultimately contributing to a better understanding of neurodegenerative disease pathology. 相似文献
4.
Mira Petrovic Marinella Farré Miren Lopez de Alda Sandra Perez Cristina Postigo Marianne Köck Jelena Radjenovic Merixell Gros Damia Barcelo 《Journal of chromatography. A》2010,1217(25):4004-4017
An overview of liquid chromatography–mass spectrometry methods used for the determination of trace organic contaminants in environmental samples is presented. Among the organic contaminants the focus is given on five groups of emerging contaminants that raised most concern as environmental contaminants and therefore attracted attention of a research community: pharmaceuticals, drugs of abuse, polar pesticides, perfluorinated compounds and nanoparticles. Various aspects of current LC–MS methodology, using tandem and hybrid MS instruments, including sample preparation, are discussed. 相似文献
5.
Analysis of carbamate pesticides in water samples using single-drop microextraction and gas chromatography–mass spectrometry 总被引:1,自引:0,他引:1
Single-drop microextraction (SDME) followed by gas chromatography–mass spectrometry detection was used for the determination
of some carbamate pesticides in water samples. The studied pesticides were thiofanox, carbofuran, pirimicarb, methiocarb,
carbaryl, propoxur, desmedipham and phenmedipham. Two alternative sample introduction methods have been examined and compared;
SDME followed by cool on-column injection (without derivatization) and SDME followed by in-microvial derivatization and splitless
injection. Acetic anhydride was used as derivatization reagent. Parameters that affect the derivatization reaction yield and
the extraction efficiency of the SDME method were studied and optimized. The analytical performances and possible applications
of both approaches were investigated. Relative standard deviations for the studied compounds ranged from 3.2 to 8.3%. The
detection limits obtained by the derivatization method were found to be in the range 3–35 ng/L. Using cool on-column injection
(without derivatization), the detection limits were between 30 and 80 ng/L. 相似文献
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José Luis Pérez Pavón Miguel del Nogal Sánchez María Esther Fernández Laespada Bernardo Moreno Cordero 《Analytical and bioanalytical chemistry》2009,394(5):1463-1470
A sensitive method for the fast analysis of filbertone in spiked olive oil samples is presented. The applicability of a headspace
(HS) autosampler in combination with a gas chromatograph (GC) equipped with a programmable temperature vaporizer (PTV) and
a mass spectrometric (MS) detector is explored. A modular accelerated column heater (MACHTM) was used to control the temperature of the capillary gas chromatography column. This module can be heated and cooled very
rapidly, shortening total analysis cycle times to a considerable extent. The proposed method does not require any previous
analyte extraction, filtration and preconcentration step, as in most methods described to date. Sample preparation is reduced
to placing the olive oil sample in the vial. This reduces the analysis time and the experimental errors associated with this
step of the analytical process. By using headspace generation, the volatiles of the sample are analysed without interference
by the non-volatile matrix, and by using injection in solvent-vent mode at the PTV inlet, most of the compounds that are more
volatile than filbertone are purged and the matrix effect is minimised. Use of a liner packed with Tenax-TA? allowed the compound
of interest to be retained during the venting process. The limits of detection and quantification were as low as 0.27 and
0.83 μg/L, respectively, and precision (measured as the relative standard deviation) was 5.7%. The method was applied to the
determination of filbertone in spiked olive oil samples and the results revealed the good accuracy obtained with the method. 相似文献
8.
Danhelova H Hradecky J Prinosilova S Cajka T Riddellova K Vaclavik L Hajslova J 《Analytical and bioanalytical chemistry》2012,403(10):2883-2889
The development and use of a fast method employing a direct analysis in real time (DART) ion source coupled to high-resolution time-of-flight mass spectrometry (TOFMS) for the quantitative analysis of caffeine in various coffee samples has been demonstrated in this study. A simple sample extraction procedure employing hot water was followed by direct, high-throughput (<1 min per run) examination of the extracts spread on a glass rod under optimized conditions of ambient mass spectrometry, without any prior chromatographic separation. For quantification of caffeine using DART-TOFMS, an external calibration was used. Isotopically labeled caffeine was used to compensate for the variations of the ion intensities of caffeine signal. Recoveries of the DART-TOFMS method were 97% for instant coffee at the spiking levels of 20 and 60 mg/g, respectively, while for roasted ground coffee, the obtained values were 106% and 107% at the spiking levels of 10 and 30 mg/g, respectively. The repeatability of the whole analytical procedure (expressed as relative standard deviation, RSD, %) was <5% for all tested spiking levels and matrices. Since the linearity range of the method was relatively narrow (two orders of magnitude), an optimization of sample dilution prior the DART-TOFMS measurement to avoid saturation of the detector was needed. 相似文献
9.
Developments in ion mobility spectrometry–mass spectrometry 总被引:4,自引:0,他引:4
Ion mobility spectrometry (IMS) has been used for over 30 years as a sensitive detector of organic compounds. The following is a brief review of IMS and its principles with an emphasis on its usage when coupled to mass spectrometry. Since its inception, IMS has been interfaced with quadrupole, time-of-flight, and Fourier-transform ion cyclotron resonance mass spectrometry. These hybrid instruments have been employed for the analysis of a variety of target analytes, including biomolecules, explosives, chemical warfare degradation products, and illicit drugs. 相似文献
10.
Cherta L Beltran J Portolés T Hernández F 《Analytical and bioanalytical chemistry》2012,402(7):2301-2314
A multiresidue method has been developed for quantification and identification of 66 multiclass priority organic pollutants
in water by fast gas chromatography (GC) coupled to mass spectrometry (MS). Capabilities and limitations of single quadrupole
mass spectrometer as detector in fast GC were studied evaluating the chromatographic responses in terms of sensitivity and
chromatographic peak shapes, as they were influenced by scan time. The number of monitored ions in a selected ion monitoring
(SIM) group strongly conditioned the scan time and subsequently the number of data points per peak. A compromise between peak
shape and scan time was adopted in order to reach the proper conditions for quantitative analysis. An average of 10–15 points
per peak was attained for most compounds, involving scan times between 0.1 and 0.22 s. The method was validated for mineral,
surface, and groundwater. A solid-phase extraction pre-concentration step using C18 cartridges was applied. Four isotopically labeled standards were added to the samples before extraction and used as surrogates
to ensure a reliable quantification. Analyses were performed by GC–MS in electron ionization mode, monitoring the three most
abundant and/or specific ions for each compound and using the intensity ratios as a confirmatory parameter. With a chromatographic
run of less than 10 min, SIM mode provided excellent sensitivity and identification capability due to the monitoring of three
ions and the evaluation of their intensity ratio. Limits of detection below 10 ng/L were reached for most of the 66 compounds
in the three matrices studied. Accuracy and precision of the method were evaluated by means of recovery experiments at two
fortification levels (10 and 100 ng/L), obtaining recoveries between 70% and 120% in most cases and relative standard deviations
below 20%. The possibilities of a simultaneous SIM scan method have also been explored for non-target qualitative analysis.
The developed method has been applied to the analysis of surface water samples collected from the Mediterranean region of
Spain. 相似文献
11.
Marie-Claude Djidja Emmanuelle Claude Marten F. Snel Simona Francese Peter Scriven Vikki Carolan Malcolm R. Clench 《Analytical and bioanalytical chemistry》2010,397(2):587-601
The development of tissue micro-array (TMA) technologies provides insights into high-throughput analysis of proteomics patterns
from a large number of archived tumour samples. In the work reported here, matrix-assisted laser desorption/ionisation–ion
mobility separation–mass spectrometry (MALDI–IMS–MS) profiling and imaging methodology has been used to visualise the distribution
of several peptides and identify them directly from TMA sections after on-tissue tryptic digestion. A novel approach that
combines MALDI–IMS–MSI and principal component analysis–discriminant analysis (PCA–DA) is described, which has the aim of
generating tumour classification models based on protein profile patterns. The molecular classification models obtained by
PCA–DA have been validated by applying the same statistical analysis to other tissue cores and patient samples. The ability
to correlate proteomic information obtained from samples with known and/or unknown clinical outcome by statistical analysis
is of great importance, since it may lead to a better understanding of tumour progression and aggressiveness and hence improve
diagnosis, prognosis as well as therapeutic treatments. The selectivity, robustness and current limitations of the methodology
are discussed. 相似文献
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It’s still a challenge for mass spectrometers (MS) to analyze samples in non-volatile salts systems. On the one hand, non-volatile salts are easy to crystallize, which will seriously contaminate and clog the transmission system of mass spectrometry, such as capillaries, ion transfer tubes, sampling cones, etc., thus the analysis results can be affected and the MS can be damaged. On the other hand, non-volatile salts always bring ion suppression, which significantly reduces the signal intensity of the analytes. At the same time, the mass spectrum will be dominated by a large number of salt cluster peaks, interfering with the discrimination of charge state. Recently, different methods have been developed to solve above two problems. This article reviewed the present research progress of mass spectrometry analysis for salt-containing samples, focusing on the role of conventional ion source modification and ambientionization mass spectrometry in the analysis of salt-containing samples. Pretreatment methods were also summarized briefly. Finally, the development tendency of mass spectrometry analysis for salt containing samples is predicted and prospected. © 2023, Youke Publishing Co.,Ltd. All rights reserved. 相似文献
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Pyrolysis gas chromatography–mass spectroscopy (PGC–MS) has been proved to be a powerful method to analyze both the volatile additives and the macromolecular structure of polymer materials. In this paper, flash evaporation technique was used to analyze the volatile degradation products of polymer materials during natural and artificial aging. In high density polyethylene (HDPE) composites, mainly n-alkanes with carbon number from 14 to 29 were detected after natural aging, while no oxidative product was found. Different composites have different n-alkane distributions. In contrast, various oxidative products including ketones, alcohols, esters and unsaturated species could be found in aged polypropylene (PP) nanocomposites. Nanoparticles accelerated the chain scission of PP and increased the formation of oxidative products significantly. During thermal oxidation of nitrile rubber (NBR) seal rubbers, heat/oxidation-induced extra crosslinking predominated and no volatile degradation products was detected. The main change happened in the volatiles is the decrease of additives, especially paraffins, antioxidant RD and hindered phenol. This resulted in the hardening of the rubber and the weakening of the protection from oxidation. Furthermore, the additive distribution along the depth was investigated, showing different migration speeds of different additives. From the additive levels remained in the NBR rubber, it is possible to predict the degradation status. In summary, PGC–MS can supply abundant information of polymer degradation and is helpful for mechanism research. 相似文献
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Zhang M Shi Z Bai Y Gao Y Hu R Zhao F 《Journal of the American Society for Mass Spectrometry》2006,17(2):189-193
This study presents a novel method for determining the molecular weights of low molecular weight (MW) energetic compounds through their complexes of beta-cyclodextrin (beta-CD) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) in a mass range of 500 to 1700 Da, avoiding matrix interference. The MWs of one composite explosive composed of 2,6-DNT, TNT, and RDX, one propellant with unknown components, and 14 single-compound explosives (RDX, HMX, 3,4-DNT, 2,6-DNT, 2,5-DNT, 2,4,6-TNT, TNAZ, DNI, BTTN, NG, TO, NTO, NP, and 662) were measured. The molecular recognition and inclusion behavior of beta-CD to energetic materials (EMs) were investigated. The results show that (1) the established method is sensitive, simple, accurate, and suitable for determining the MWs of low-MW single-compound explosives and energetic components in composite explosives and propellants; and (2) beta-CD has good inclusion and modular recognition abilities to the above EMs. 相似文献
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Marcio David Bocelli Deyber Arley Vargas Medina Julie Paulin García Rodriguez Fernando Mauro Lanças Álvaro José Santos-Neto 《Electrophoresis》2022,43(15):1567-1576
Dynamic single-drop microextraction (SDME) was automatized employing an Arduino-based lab-made Cartesian robot and implemented to determine parabens in wastewater samples in combination with liquid chromatography–tandem mass spectrometry. A dedicated Arduino sketch controls the auto-performance of all the stages of the SDME process, including syringe filling, drop exposition, solvent recycling, and extract collection. Univariate and multivariate experiments investigated the main variables affecting the SDME performance, including robot-dependent and additional operational parameters. Under selected conditions, limit of detections were established at 0.3 µg/L for all the analytes, and the method provided linear responses in the range between 0.6 and 10 µg/L, with adequate reproducibility, measured as intraday relative standard deviations (RSDs) between 5.54% and 17.94%, (n = 6), and inter-days RSDs between 8.97% and 16.49% (n = 9). The robot-assisted technique eased the control of dynamic SDME, making the process more feasible, robust, and reliable so that the developed setup demonstrated to be a competitive strategy for the automated extraction of organic pollutants from water samples. 相似文献