共查询到20条相似文献,搜索用时 46 毫秒
1.
Myroslav V. Zoriy J. Sabine Becker 《Rapid communications in mass spectrometry : RCM》2009,23(1):23-30
An analytical technique utilizing a near‐field effect (to enhance the incident light energy on the thin tip of an Ag needle) in a laser ablation inductively coupled plasma mass spectrometry (NF‐LA‐ICP‐MS) procedure was developed. To produce the thin needles with a tip diameter in the hundreds of nm range a robust needle etching procedure was established. The ‘sample‐to‐tip’ distance was controlled via the measurement of a tunnel current between the needle and sample surface. The NF‐LA‐ICP‐MS technique thus developed was applied for the analysis of copper isotopic standard reference material NIST SRM 976 and tungsten‐molybdenum alloy NIST SRM 480 in the nm resolution range. The observed craters ranged from 200 nm to about 2 µm in diameter and were dependent on the needle used as well as on the ‘sample‐to‐tip’ distance. The mass spectrometric measurements of 63Cu+ ion intensity on NIST SRM 976 showed that using near‐field enhancement in laser ablation allowed a roughly 6‐fold increase in the ion intensity of the analyte when the needle was about 100 nm (and below) from the surface, in contrast to when it was far away (e.g. 10 µm) from the sample. The relative standard deviation (RSD) of the 65Cu+/63Cu+ isotopic ratio measurements by NF‐LA‐ICP‐MS was 3.9% (n = 9). The detection efficiencies obtained for the compared LA‐ICP‐MS and NF‐LA‐ICP‐MS methods were found to be 4.6 * 10?3 counts per second (cps)/ablated atom and 2.7 * 10?5 cps/ablated atom, respectively. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
2.
Jungmann JH MacAleese L Buijs R Giskes F de Snaijer A Visser J Visschers J Vrakking MJ Heeren RM 《Journal of the American Society for Mass Spectrometry》2010,21(12):2023-2030
In mass spectrometry imaging, spatial resolution is pushed to its limits with the use of ion microscope mass spectrometric
imaging systems. An ion microscope magnifies and then projects the original spatial distribution of ions from a sample surface
onto a position-sensitive detector, while retaining time-of-flight mass separation capabilities. Here, a new type of position-sensitive
detector based on a chevron microchannel plate stack in combination with a 512 × 512 complementary metal-oxide-semiconductor
based pixel detector is coupled to an ion microscope. Spatial resolving power better than 6 μm is demonstrated by secondary
ion mass spectrometry and 8–10μm spatial resolving power is achieved with laser desorption ionization. A detailed evaluation
of key performance criteria such as spatial resolution, acquisition speed, and data handling is presented. 相似文献
3.
Bamberger C Renz U Bamberger A 《Journal of the American Society for Mass Spectrometry》2011,22(6):1079-1087
Methods to visualize the two-dimensional (2D) distribution of molecules by mass spectrometric imaging evolve rapidly and yield
novel applications in biology, medicine, and material surface sciences. Most mass spectrometric imagers acquire high mass
resolution spectra spot-by-spot and thereby scan the object’s surface. Thus, imaging is slow and image reconstruction remains
cumbersome. Here we describe an imaging mass spectrometer that exploits the true imaging capabilities by ion optical means
for the time of flight mass separation. The mass spectrometer is equipped with the ASIC Timepix chip as an array detector
to acquire the position, mass, and intensity of ions that are imaged by matrix-assisted laser desorption/ionization (MALDI)
directly from the target sample onto the detector. This imaging mass spectrometer has a spatial resolving power at the specimen
of (84 ± 35) μm with a mass resolution of 45 and locates atoms or organic compounds on a surface area up to ~2 cm2. Extended laser spots of ~5 mm2 on structured specimens allows parallel imaging of selected masses. The digital imaging mass spectrometer proves high hit-multiplicity,
straightforward image reconstruction, and potential for high-speed readout at 4 kHz or more. This device demonstrates a simple
way of true image acquisition like a digital photographic camera. The technology may enable a fast analysis of biomolecular
samples in near future. 相似文献
4.
Lee Chuin Chen Kentaro Yoshimura Zhan Yu Rikiya Iwata Hajime Ito Hiroaki Suzuki Kunihiko Mori Osamu Ariyada Sen Takeda Takeo Kubota Kenzo Hiraoka 《Journal of mass spectrometry : JMS》2009,44(10):1469-1477
Although being an atmospheric pressure ion source, electrospray ionization (ESI) has rarely been used directly for ambient imaging mass spectrometry because the sample has to be introduced as liquid solution through the capillary. Instead of capillary, probe electrospray ionization (PESI), which has been developed recently, uses a solid needle as the sampling probe, as well as the electrospray emitter, and has been applied not only for liquid solutions but also for the direct sampling on wet samples. Biological tissues are composed of cells that contain 70–90% water, and when the surface is probed by the needle tip, the biological fluid adhering to the needle can be electrosprayed directly or assisted by additional solvent added onto the needle surface. Here, we demonstrate ambient imaging mass spectrometry of mouse brain section using PESI, incorporated with an auxiliary heated capillary sprayer. The solvent vapor generated from the sprayer condensed on the needle tip, re‐dissolving the adhered sample, and at the same time, providing an indirect means for needle cleaning. The histological sections were prepared by fixation using paraformaldehyde, and the spatial analysis was automated by maintaining an equal sampling depth into the sample in addition to raster scan. Phospholipids and galactosylceramides were readily detected from the mouse brain section in the positive ion mode, and were mapped with 60 µm lateral resolution to form mass spectrometric images. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
5.
A method to obtain laser desorption/ionization mass spectra of organic compounds by depositing sample solutions onto a carbon substrate surface is demonstrated. The substrate consists of a thin layer of activated carbon particles immobilized on an aluminum support. In common with the porous carbon suspension samples used in previous “surface-assisted laser desorption/ionization” (SALDI) work, the mass spectra contain only a few “matrix” background ion peaks, minimizing interference with analyte ion peaks. The presence of glycerol ensured that the ion signals were stable over hundreds of laser shots. In addition, the carbon substrate surface has several advantages over the suspension samples. The use of a very thin layer of carbon significantly improves the sensitivity. Detection limits range from attomoles for crystal violet to femtomoles for bradykinin. Very little sample preparation is required as the analyte solution is simply pipetted onto the substrate surface and glycerol added. When using an alternate sample deposition method, a mass resolution for bradykinin of 1800 is achieved in linear time-of-flight mode. This is close to the resolution limit set by the detector system and above instrument specification for matrix-assisted laser desorption/ionization mass spectra. 相似文献
6.
Gabriel Munoz Sung Vo Duy Hélène Budzinski Pierre Labadie Jinxia Liu Sébastien Sauvé 《Analytica chimica acta》2015
An alternative analysis technique for the quantitation of 15 poly- and perfluoroalkyl substances (PFASs) in water matrices is reported. Analysis time between each sample was reduced to less than 20 s, all target molecules being analyzed in a single run with the use of laser diode thermal desorption atmospheric pressure chemical ionization (LDTD/APCI) coupled with high resolution accurate mass (HRMS) orbitrap mass spectrometry. LDTD optimal settings were investigated using either one-factor-at-a-time or experimental design methodologies, while orbitrap parameters were optimized simultaneously by means of a Box–Behnken design. Following selection of an adequate sample concentration and purification procedure based on solid-phase extraction and graphite clean-up, the method was validated in an influent wastewater matrix. Environmentally significant limits of detection were reported (0.3–4 ng L−1 in wastewater and 0.03–0.2 ng L−1 in surface water) and out of the 15 target analytes, 11 showed excellent accuracies (±20% of the target values) and recovery rates (75–125%). The method was successfully applied to a selection of environmental samples, including wastewater samples in 7 locations across Canada, as well as surface and tap water samples from the Montreal region, providing insights into the degree of PFAS contamination in this area. 相似文献
7.
Smirnov IP Hall LR Ross PL Haff LA 《Rapid communications in mass spectrometry : RCM》2001,15(16):1427-1432
The susceptibility of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) to the presence of salts in a sample, especially salts of alkali metals, requires careful and often tedious desalting procedures which complicate and slow the throughput of MS-based methods. A novel approach to sample preparation was developed based on the extraction of DNA out of solution onto a solid surface with an attached DNA-binding polymer, such as polyethyleneimine or polyvinylpyrrolidone. The observed binding is strong enough to sustain washing, and, as a result, desalting and concentration can be performed in a single fast step. After DNA has been immobilized on the surface and supernatant solution removed, subsequent addition of MALDI matrix releases material from the surface, which co-crystallizes with matrix. The mass spectrometric analysis is then performed directly from this support. Analysis of oligonucleotides and three-fold multiplexed SNP typing reactions performed by this method shows improved sensitivity and excellent resolution for various DNA fragments, together with high tolerance to various buffer components, such as alkali metals and surfactants. Simplicity and speed make it attractive for high-throughput sample preparation and analysis of oligonucleotide mixtures by MALDI-MS. 相似文献
8.
Determination of heavy metal complexes with humic substances by HPLC/ICP-MS coupling using on-line isotope dilution technique 总被引:3,自引:0,他引:3
An isotope dilution mass spectrometric (IDMS) method has been developed for the simultaneous determination of the complexes
of 11 heavy metals (Ag, Cd, Cu, Mo, Ni, Pb, Tl, U, W, Zn and Zr) with humic substances (HS) by coupling HPLC with ICP-MS and
applying the on-line isotope dilution technique. The HPLC separation was carried out with size exclusion chromatography. This
HPLC/ICP-IDMS method was applied to samples from a brown water, ground water, sewage and seepage water as well as for a sample
containing isolated fulvic acids. The total contents of heavy metals and of their complexes were analyzed in these samples
with detection limits in the range of 5–110 ng/L. The analysis of heavy metal/HS complexes from the different waters resulted
in characteristic fingerprints of the distribution pattern of heavy metals in the separated HS fractions. A comparison between
the total heavy metal concentrations and their portions bound to humic substances showed distinct differences for the various
metals. Simultaneous 12C detection was used for the characterization of HS complexes not identified by UV detection and for the determination of
relative DOC concentrations of chromatographic peaks.
Received: 21 February 1997 / Revised: 27 May 1997 / Accepted: 28 May 1997 相似文献
9.
Baralkiewicz Danuta El-Sayed Usama Filipiak Marian Gramowska Hanka Mleczek Miroslaw 《Central European Journal of Chemistry》2004,2(2):334-346
Slurry sampling electrothermal atomic absorption (SS ETAAS) was applied to the development of a sensitive and precise method
for selenium determination in infant foods without sample pretreatment. Suspensions prepared in a medium containing 0.1% Triton
X-100, 0.5 or 5% v/v concentrated HNO3 were directly introduced into the furnace. The accuracy of the procedure was confirmed by analysis of a standard reference
material and comparison with hydride generation atomic absorption spectrometric (HGAAS) procedure. The characteristic mass
is 44 pg and detection limit 0.43 μg·l−1. 相似文献
10.
《Spectrochimica Acta Part B: Atomic Spectroscopy》1998,53(11):1475-1506
Mass spectrometric methods for the trace analysis of inorganic materials with their ability to provide a very sensitive multielemental analysis have been established for the determination of trace and ultratrace elements in high-purity materials (metals, semiconductors and insulators), in different technical samples (e.g. alloys, pure chemicals, ceramics, thin films, ion-implanted semiconductors), in environmental samples (waters, soils, biological and medical materials) and geological samples. Whereas such techniques as spark source mass spectrometry (SSMS), laser ionization mass spectrometry (LIMS), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), glow discharge mass spectrometry (GDMS), secondary ion mass spectrometry (SIMS) and inductively coupled plasma mass spectrometry (ICP-MS) have multielemental capability, other methods such as thermal ionization mass spectrometry (TIMS), accelerator mass spectrometry (AMS) and resonance ionization mass spectrometry (RIMS) have been used for sensitive mono- or oligoelemental ultratrace analysis (and precise determination of isotopic ratios) in solid samples. The limits of detection for chemical elements using these mass spectrometric techniques are in the low ng g−1 concentration range. The quantification of the analytical results of mass spectrometric methods is sometimes difficult due to a lack of matrix-fitted multielement standard reference materials (SRMs) for many solid samples. Therefore, owing to the simple quantification procedure of the aqueous solution, inductively coupled plasma mass spectrometry (ICP-MS) is being increasingly used for the characterization of solid samples after sample dissolution. ICP-MS is often combined with special sample introduction equipment (e.g. flow injection, hydride generation, high performance liquid chromatography (HPLC) or electrothermal vaporization) or an off-line matrix separation and enrichment of trace impurities (especially for characterization of high-purity materials and environmental samples) is used in order to improve the detection limits of trace elements. Furthermore, the determination of chemical elements in the trace and ultratrace concentration range is often difficult and can be disturbed through mass interferences of analyte ions by molecular ions at the same nominal mass. By applying double-focusing sector field mass spectrometry at the required mass resolution—by the mass spectrometric separation of molecular ions from the analyte ions—it is often possible to overcome these interference problems. Commercial instrumental equipment, the capability (detection limits, accuracy, precision) and the analytical application fields of mass spectrometric methods for the determination of trace and ultratrace elements and for surface analysis are discussed. 相似文献
11.
Cahill MG Caprioli G Stack M Vittori S James KJ 《Analytical and bioanalytical chemistry》2011,400(2):587-594
Effluent from wastewater treatment plants have been identified as an important source of micro-organic contaminants in the
environment. An online high-performance liquid chromatography–heated electrospray ionization tandem mass spectrometric method
was developed and validated for the determination of basic pesticides in effluent wastewaters. Most available methods for
pesticide analysis of wastewater samples are time-consuming, require complex clean-up steps and are difficult to automate.
The method developed used a simple solid-phase extraction clean-up for salt and lipid reduction. On-line sample pre-concentration
was performed using a reversed phase (C18) column, and analytes were separated by back-flushing onto an analytical column (C8) with detection using QqQ MS. An option to increase MS resolution was exploited to minimize interference from endogenous
compounds in the matrix. A better than unit mass resolution was used (Q1 full width half maximum (FWHM) = 0.2 Da and Q3 FWHM = 0.7 Da),
which was as rugged as a unit resolution method, and improved signal/noise and better detection limits were achieved for the
targeted basic pesticides. This method was applied to the determination of 11 pesticides, including methoxytriazine, chlorotriazines,
chloroacetanilides, phenylurea and carbamate pesticides. The percentage recovery values for these pesticides using the online
trapping column were within the range, 73–95%, with relative standard deviation (RSD) values <8.9%. The highest concentrations
of these pesticides in wastewater effluents in County Cork, Ireland, were simazine (0.51 μg/L), prometon (0.14 μg/L), diuron
(0.21 μg/L) and atrazine (0.19 μg/L). 相似文献
12.
在自行研制的LI-TOF-MS[6]的基础上, 发展了新的LI-TOF-MS固体元素成像分析系统, 并在优化了的实验条件下, 对辉锑矿矿石样品(主要成分为Sb2S3)的表面进行了元素分析, 得到了Sb, S, Si, Al, K, Ca和Fe等元素的表面成像图. 矿石表面或截面的元素成像(或分布)对矿石乃至矿床的形成过程及分布特征等的研究具有很大的参考价值, 在地质学上具有重要意义. 相似文献
13.
A. I. Saprykin J. S. Becker H.-J. Dietze 《Fresenius' Journal of Analytical Chemistry》1999,364(8):763-767
A radiofrequency (rf) spark discharge in vacuum developing across the surface of dielectrics – a so-called gliding spark
– has been applied to the direct mass spectrometric trace analysis of nonconducting materials. The special configuration of
the electrodes strengthened the electric field over the surface of a nonconducting sample and created optimum conditions for
the sputtering and ionization of the sample material. Mass spectrometric investigations of the charge composition of atomic
ion and molecular ion formation in radiofrequency gliding spark plasma showed a significant difference to that of the original
rf spark discharge between two conducting electrodes. The analytical figures of merit (reproducibility, relative sensitivity
factors and detection limits of chemical elements) of gliding spark source mass spectrometry have been studied by using the
glass standard reference materials NIST SRM 610 and 611 for the determination of trace elements in glass matrix.
Received: 31 March 1999 / Revised: 10 May 1999 / Accepted: 13 May 1999 相似文献
14.
A new instrument and method is described for laterally resolved mass spectrometric surface analysis. Fields of application are in both the life sciences and the material sciences. The instrument provides for imaging of the distribution of selected sample components from natural and artificial surfaces. Samples are either analyzed by laser desorption ionization (LDI) time-of-flight mass spectrometry or, after preparation with a suitable matrix, by matrix-assisted laser desorption ionization (MALDI) mass spectrometry. Areas of 100 x 100 microm are scanned with minimal increments of 0.25 microm, and between 10,000 and 160,000 mass spectra are acquired per image within 3 to 50 min (scan rate up to 50 pixels per s). The effective lateral resolution is in the range of 0.6 to 1.5 microm depending on sample properties, preparation methods and laser wavelength. Optical investigation of the same sample area by UV confocal scanning laser microscopy was found to be very attractive in combination with scanning MALDI mass analysis because pixel-identical images can be created with both techniques providing for a strong increase in analytical information. This article describes the method and instrumentation, including first applicational examples in elemental analysis, imaging of pine tree roots, and investigation of MALDI sample morphology in biomolecular analysis. 相似文献
15.
Anthony P. Gies Anton Schotman David M. Hercules 《Analytical and bioanalytical chemistry》2010,396(4):1481-1490
In the present study, we address the possibility of matrix-assisted laser desorption/ionization (MALDI)–time-of-flight MS
analysis-induced chain fragmentation in poly(p-phenylene terephthalamide) (PPD-T) by considering two possible sources: (1) grinding-induced fragmentation resulting from
the evaporation–grinding MALDI sample preparation method (E-G method) and (2) in-source/metastable fragmentation induced by
the MALDI laser. An analysis of variance (ANOVA) statistical study found, with a high probability, that obtaining MALDI spectra
with the effective laser area as large as possible (the “fanned-out” setting) did not cause any chain fragmentation due to
the E-G MALDI sample preparation method, even when three additional grinding steps were used. However, the effect of laser
fluence was less clear. A significant effect of laser fluence was observed for lower mass oligomers (<1,400 Da), but there
was essentially no effect for higher mass species up to our limit of ANOVA measurement (∼2,300 Da). Plausible explanations
are presented to explain these observations. The most likely scenario is that “unexpected” end-group modifications occur during
PPD-T synthesis, producing small quantities of low mass species, which are amplified by the MALDI-EG extraction procedure. 相似文献
16.
J. Sabine Becker 《Journal of mass spectrometry : JMS》2013,48(2):255-268
Laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) is well established as a sensitive trace and ultratrace analytical technique with multielement capability for bioimaging of metals and studying metallomics in biological and medical tissue. Metals and metalloproteins play a key role in the metabolism and formation of metal‐containing deposits in the brain but also in the liver. In various diseases, analysis of metals and metalloproteins is essential for understanding the underlying cellular processes. LA–ICP–MS imaging (LA–ICP–MSI) combined with other complementary imaging techniques is a sophisticated tool for investigating the regional and cellular distribution of metals and related metal‐containing biomolecules. On the basis of successful routine techniques for the elemental bioimaging of cryosections by LA–ICP–MSI with a spatial resolution between 200 and ~10 µm, the further development used online laser microdissection ICP–MSI to study the metal distribution in small biological sample sections (at the cellular level from 10 µm to the submicrometer range). The use of mass spectrometric imaging of metals and also nonmetals is demonstrated on a series of biological specimens. This article discusses the state of the art of bioimaging of metals in thin biological tissue sections by LA–ICP–MSI with spatial resolution at the micrometer scale, future developments and prospects for quantitative imaging techniques of metals in the nanometer range. In addition, combining quantitative elemental imaging by LA/laser microdissection–ICP–MSI with biomolecular imaging by matrix‐assisted laser desorption/ionization–MSI will be challenging for future life science research. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
17.
George Perkins Frank Pullen Christine Thompson 《Journal of the American Society for Mass Spectrometry》1999,10(6):546-551
Exact mass measurement at high resolution is an important tool alongside other spectroscopic methods to help confirm the structure of a novel compound prepared by the synthetic chemist. Exact mass measurement is used in the pharmaceutical industry to confirm the expected empirical formula of a product when problems have been experienced using elemental analysis. Because of the amount of manual intervention necessary when acquiring exact mass measurements, especially when using probe ionization techniques such as fast atom bombardment ionization or electron ionization, this method has been seen to be time consuming and labor intensive for the mass spectrometrist. An automated high resolution mass spectrometric method has been developed at Pfizer Central Research which has streamlined exact mass measurement. The method, which uses electrospray ionization on a double focusing mass spectrometer, is described. The samples are analyzed using a flow injection technique, with sodiated polyethylene glycol present in the mobile phase to provide mass reference peaks. The data are acquired and processed using a macro developed “in house.” This automated technique can process 15–20 samples an hour including data processing and report generation, using very small amounts of compound (∼25 μg), but more importantly it can be left to run unattended overnight. This allows the instrument to be used for more complex experiments during the day when it is important to have a mass spectrometrist present. The results presented here demonstrate that this method gives exact mass measurements within an acceptable limit of 5 ppm, and the variation on one sample, injected 10 times, is not excessively high (−1.8 to +1.6 mDa). 相似文献
18.
A method involving simultaneous extraction and sample clean-up procedure: hollow fiber sorptive microextraction, coupled with
gas chromatography–mass spectrometric detection for quantification of seven organochlorine pesticides in Radix et Rhizoma
Rhei is described. SiO2 hollow fiber with porous structure was synthesized for the first time. The internal diameter of SiO2 hollow fiber is 380 μm and average wall thickness is 100 μm. Aggregated SiO2 particles deposited on the surface of the hollow fiber in a regular array lead to porous structure. SiO2 hollow fiber was applied to the determination of organochlorine pesticides in Radix et Rhizoma Rhei to avoid sample clean-up
and minimize the matrix effects. Extraction solvent, extraction temperature and equilibration time were optimized. Fiber to
fiber repeatability over the concentration ranges were less than 10%. Recoveries were satisfactory (between 63% and 115%)
for most of organochlorine pesticides at spiking levels. Furthermore, the proposed method was also applied to determine seven
organochlorine pesticides in 43 commercial Radix et Rhizoma Rhei samples, in which the selected pesticides were found in eight
samples. The results have been further confirmed by solvent extraction methods according to China Pharmacopoeia (2005). 相似文献
19.
Chen KY Yang TC Chang SY 《Journal of the American Society for Mass Spectrometry》2012,23(6):1157-1160
A novel method for the determination of macrolide antibiotics using dispersive liquid–liquid microextraction coupled to surface-assisted
laser desorption/ionization mass spectrometric detection was developed. Acetone and dichloromethane were used as the disperser
solvent and extraction solvent, respectively. A mixture of extraction solvent and disperser solvent were rapidly injected
into a 1.0 mL aqueous sample to form a cloudy solution. After the extraction, macrolide antibiotics were detected using surface-assisted
laser desorption/ionization mass spectrometry (SALDI/MS) with colloidal silver as the matrix. Under optimum conditions, the
limits of detection (LODs) at a signal-to-noise ratio of 3 were 2, 3, 3, and 2 nM for erythromycin (ERY), spiramycin (SPI),
tilmicosin (TILM), and tylosin (TYL), respectively. This developed method was successfully applied to the determination of
macrolide antibiotics in human urine samples. 相似文献
20.
Olga S. Ovchinnikova Vilmos Kertesz Gary J. Van Berkel 《Rapid communications in mass spectrometry : RCM》2011,25(24):3735-3740
This paper describes the coupling of ambient pressure transmission geometry laser ablation with a liquid‐phase sample collection into a continuous flow surface sampling probe/electrospray emitter for mass spectrometry based chemical imaging. The flow probe/emitter device was placed in close proximity to the surface to collect the sample plume produced by laser ablation. The sample collected was immediately aspirated into the probe and onto the electrospray emitter, ionized and detected with the mass spectrometer. Freehand drawn ink lines and letters and an inked fingerprint on microscope slides were analyzed. The circular laser ablation area was about 210 µm in diameter and under the conditions used in these experiments the spatial resolution, as determined by the size of the surface features distinguished in the chemical images, was about 100 µm. Published in 2011 by John Wiley & Sons, Ltd. 相似文献