著者

Masahiro Hashimoto Haruo Iwabuchi Takaya Satoh

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0139, 2023-12-12 (Released:2023-12-12)

参考文献数

12

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Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) is a suitable method for polymer analysis. MALDI is a soft ionization technique that can generate mainly singly charged ions. Therefore, the polymer’s molecular weight distribution is easy to analyze, facilitating the calculation of the number average molecular weight and weight average molecular weight and polydispersity. However, there are polymers that are difficult to detect by MALDI-TOFMS. For example, polyacrylic acid includes carboxylic acid in the main chain, which is difficult to measure due to its low ionization efficiency. As a solution, the ionization efficiency was improved by methylation. In this technical report, we introduce a method to utilize derivatization to determine the degree of polymerization by accurate mass spectrometry (MS). Furthermore, the structures of both ends of the polymers were estimated by tandem time-of-flight MS.

著者

Daisuke Saigusa Ritsumi Saito Komei Kawamoto Akira Uruno Kuniyuki Kano Shuichi Shimma Junken Aoki Masayuki Yamamoto Tadafumi Kawamoto

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0137, 2023-12-12 (Released:2023-12-12)

参考文献数

16

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The matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) technique was used to obtain the molecular images of cryosections without labeling. Although MALDI-MSI has been widely used to detect small molecules from biological tissues, issues remain due to the technical process of cryosectioning and limited mass spectrometry parameters. The use of a conductive adhesive film is a unique method to obtain high-quality sections from cutting tissue, such as bone, muscle, adipose tissue, and whole body of mice or fish, and we have reported the utilization of the film for MALDI-MSI in previous. However, some signal of the small molecules using the conductive adhesive films was still lower than on the indium tin oxide (ITO) glass slide. Here, the sample preparation and analytical conditions for MALDI-MSI using an advanced conductive adhesive film were optimized to obtain strong signals from whole mice heads. The effects of tissue thickness and laser ionization power on signal intensity were verified using MALDI-MSI. The phospholipid signal intensity was measured for samples with three tissue thicknesses (5, 10, and 20 μm); compared to the signals from the samples on the ITO glass slides, the signals with conductive adhesive films exhibited significantly higher intensities when a laser with a higher range of power was used to ionize the small molecules. Thus, the technique using the advanced conductive adhesive film showed an improvement in MALDI-MSI analysis.

著者

Fumio Matsuda

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0138, 2023-12-08 (Released:2023-12-08)

参考文献数

37

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Non-targeted metabolome analysis studies comprehensively acquire product ion spectra from the observed ions by the data-dependent acquisition (DDA) mode of tandem mass spectrometry (MS). A DDA dataset redundantly contains closely similar product ion spectra of metabolites commonly existing among the biological samples analyzed in a metabolome study. Moreover, a single DDA data file often includes two or more closely similar raw spectra obtained from an identical precursor ion. The redundancy of product ion spectra has been used to generate an averaged product ion spectrum from a set of similar product ion spectra recorded in a DDA dataset. The spectral averaging improved the accuracy of m/z values and signal-to-noise levels of product ion spectra. However, the origins of redundancy, variations among datasets, and these effects on the spectral averaging procedure needed to be better characterized. This study investigated the nature of the redundancy by comparing the averaging results of eight DDA datasets of non-targeted metabolomics studies. The comparison revealed a significant variation in redundancy among datasets. The DDA datasets obtained by the quadrupole (Q)-Orbitrap-MS datasets had more significant intrafile redundancy than that of the Q-time-of-flight-MS. For evaluating the similarity score between two product ion spectra, the optimal threshold level of the cosine-product method was approximately 0.8–0.9. Moreover, contamination of biological samples such as plasticizers was another origin of spectral redundancy. The results will be the basis for further development of methods for processing of product ion spectra data.

著者

Kevin M. Downard

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0136, 2023-12-01 (Released:2023-12-01)

参考文献数

85

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This review article presents the development and application of mass spectrometry (MS) approaches, developed in the author’s laboratory over the past 25 years, to detect; characterise, type and subtype; and distinguish major variants and subvariants of respiratory viruses such as influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). All features make use of matrix-assisted laser desorption ionisation (MALDI) mass maps, recorded for individual viral proteins or whole virus digests. A MALDI-based immunoassay in which antibody–peptide complexes were preserved on conventional MALDI targets without their immobilisation led to an approach that enabled their indirect detection. The site of binding, and thus the molecular antigenicity of viruses, could be determined. The same approach was employed to study antivirals bound to their target viral protein, the nature of the binding residues, and relative binding affinities. The benefits of high-resolution MS were exploited to detect sequence-conserved signature peptides of unique mass within whole virus and single protein digests. These enabled viruses to be typed, subtyped, their lineage determined, and variants and subvariants to be distinguished. Their detection using selected ion monitoring improved analytical sensitivity limits to aid the identification of viruses in clinical specimens. The same high-resolution mass map data, for a wide range of viral strains, were input into a purpose-built algorithm (MassTree) in order to both chart and interrogate viral evolution. Without the need for gene or protein sequences, or any sequence alignment, this phylonumerics approach also determines and displays single-point mutations associated with viral protein evolution in a single-tree building step.

著者

Riko Takata Yuji Nakabayashi Kotaro Hashimoto Akio Miyazato Issey Osaka

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0135, 2023-11-25 (Released:2023-11-25)

参考文献数

23

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Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) has been widely used for analyses of biomolecules and industrial materials. Surface-assisted laser desorption/ionization (SALDI) is studied to complement the ionization ability for the MALDI/MS. In this study, lab-made mist chemical vapor deposition (mist CVD) system was used to produce metal films as ionization assistance materials for SALDI/MS. The system could give Ag film from inexpensive silver trifluoroacetate solution rapidly and simply under atmospheric pressure. Phosphatidylcholines could be detected high sensitively and diacylglycerols (DAGs) could not be detected in MALDI/MS. In the SALDI/MS and the MS imaging with Ag film by mist CVD, both the phosphatidylcholines and the DAGs could be detected and the localized images. In the Ag film-SALDI/MS of lipids, not only Ag-adducted ions but also Na- and K-adducted ions were detected. The Ag film formed by the mist CVD to act as an ionization-assistance material and a cationization agent in SALDI would be useful in MS imaging of biological tissue sections.

著者

Takashi Maoka

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0133, 2023-11-01 (Released:2023-11-01)

参考文献数

35

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Carotenoids are tetraterpene pigments that are present in photosynthetic bacteria, some species of archaea and fungi, algae, plants, and animals. Carotenoids are essential pigments in photosynthetic organs along with chlorophylls. Carotenoids also act as photo-protectors, antioxidants, color attractants, and precursors of plant hormones in plants. Carotenoids in animals play important roles, such as precursors of vitamin A, photo-protectors, antioxidants, enhancers of immunity, and contributors to reproduction. More than 850 kinds of carotenoids are present in nature. The structures are similar and all of them are labile. Analysis of natural carotenoids requires the establishment of reliable methods for analyzing them. Liquid chromatography–mass spectrometry (LC-MS) and mass spectrometry/mass spectrometry (MS/MS) coupled with photodiode array detector (DAD) is an important tool for analysis of natural carotenoids. Electrospray ionization and atmospheric pressure chemical ionization are commonly used for ionization of LC-MS of carotenoids. MS and MS/MS provide not only molecular weight information but also some structural information on carotenoids. Ultraviolet-visible spectra from DAD provide information on chromophore systems, which cannot be provided by MS spectral data. In the present review, I report the structural diversity and function of natural carotenoids, and also describe the techniques for analysis of natural carotenoids using the LC-DAD-MS and MS/MS system.

著者

Shuichi Shimma Hiromi Saito Takuya Inoue Fukumatsu Iwahashi

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0132, 2023-10-12 (Released:2023-10-12)

参考文献数

26

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Pesticide seed treatment provides efficient crop protection in the early season and enables a reduction in the quantity of fungicides used later. Hence, it has been a practical application for crop protection in major crop sectors such as corn, soybean, wheat, and cotton. The chemicals on pesticide-treated seeds may show different distributions depending on the structure of the seeds and the physical properties of the chemicals, but they have not been well studied because of a lack of versatile analytical tools. Here, we used mass spectrometry imaging to visualize the distribution of a fungicide (ethaboxam) in corn and soybean seeds coated with it. Contrasting distribution patterns were noted, which are likely dependent on the seed structure. We also obtained information on fungicide distribution after the seedings, which will contribute to a better understanding of the fungicide delivery pathway within plants. Using this new analytical method, we were able to obtain hitherto unavailable time-dependent, dynamic information on the ethaboxam. We expect that this method will be a useful tool with widespread applications in pesticide development and use.

著者

Bharath S. Kumar

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0129, 2023-09-28 (Released:2023-09-28)

参考文献数

123

被引用文献数

1

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Cancer metabolic variability has a significant impact on both diagnosis and treatment outcomes. The discovery of novel biological indicators and metabolic dysregulation, can significantly rely on comprehension of the modified metabolism in cancer, is a research focus. Tissue histology is a critical feature in the diagnostic testing of many ailments, such as cancer. To assess the surgical margin of the tumour on patients, frozen section histology is a tedious, laborious, and typically arbitrary method. Concurrent monitoring of ion images in tissues facilitated by the latest advancements in mass spectrometry imaging (MSI) is far more efficient than optical tissue image analysis utilized in conventional histopathology examination. This article focuses on the “desorption electrospray ionization (DESI)-MSI” technique’s most recent advancements and uses in cancer research. DESI-MSI can provide wealthy information based on the variances in metabolites and lipids in normal and cancerous tissues by acquiring ion images of the lipid and metabolite variances on biopsy samples. As opposed to a systematic review, this article offers a synopsis of the most widely employed cutting-edge DESI-MSI techniques in cancer research.

著者

Erika Nagano Kazuki Odake Shuichi Shimma

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0128, 2023-07-25 (Released:2023-07-25)

参考文献数

27

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Mass spectrometry imaging (MSI) is a well-known method for the ionization of molecules on tissue sections and the visualization of their localization. Recently, different sample preparation methods and new instruments have been used for MSI, and different molecules are becoming visible. On the other hand, although several quantification methods (q-MSI) have been proposed, there is still room for the development of a simplified procedure. Here, we have attempted to develop a reproducible and reliable quantification method using a calibration curve prepared from tissue debris of a frozen section of a sample when we trim the frozen blocks. We discuss the reproducibility of this method across different sample lots and the effect of the biological matrix (ion suppression) on our results. The quantitative performance was evaluated in terms of accuracy and relative standard deviation, and the reliability of the quantitative values obtained by matrix-assisted laser desorption/ionization-MSI was further evaluated by enzyme-linked immunosorbent assay (ELISA). Our q-MSI method for the quantification of dopamine in mouse brain tissue was found to be highly linear, accurate, and precise. The quantitative values obtained by MSI were found to be highly comparable (>85% similarity) to the results obtained by ELISA from the same tissue extracts.

著者

Yuto Nishikido Kanako Sekimoto

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0127, 2023-07-29 (Released:2023-07-29)

参考文献数

19

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The ionization and fragmentation patterns of 24 compounds with elemental composition of CmH2mO2, including isomeric esters and alkanoic acids, were investigated by atmospheric pressure corona discharge ionization collision-induced dissociation (CID) mass spectrometry in the positive-ion mode. All compounds were ionized as protonated molecules and NH4+ adducts. In addition, fragment ions were observed in mass spectra of esters other than methyl esters, which are owing to the dissociation of the alkyl group in the alcohol side from the protonated molecules. In CID spectra, protonated alkanoic acids/methyl esters split off H2O/CH3OH and CO or the alkyl group in the acid side, depending on the carbon chain length. Protonated esters (other than methyl esters) mainly fragmented the alkyl group in the alcohol side. These general rules on ionization and fragmentation patterns can provide relevant information on the discrimination of isomers.

著者

Raju Bandu Hyun Jeong Lee Hyeong Min Lee Tae Hyon Ha Heon-Jeong Lee Se Joo Kim Kyooseob Ha Kwang Pyo Kim

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0123, 2023-07-06 (Released:2023-07-06)

参考文献数

32

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Liquid chromatography/electrospray ionization-mass spectrometry revealed plasma metabolic profiles for the antidepressant drug escitalopram (ECTP) and associated clinical responses in subjects with major depressive disorder (MDD). Metabolic profiles contribute to variations in responses to drug treatment of depression. To assess clinical responses and treatment outcomes, we quantified the levels of metabolites, including those of the parent drug, in plasma samples collected at different time points (days 0, 7, 14, and 42) during treatment of seven patients with MDD. Results showed that mean plasma levels of key metabolites and ECTP at day 7 were significantly associated with the clinical response at 42 days after treatment. Statistical analyses, including principal component analysis, of key metabolites and ECTP samples at different time points clearly distinguished the clinical responders from non-responder subjects. Although further validation with a larger cohort is necessary, our results indicate that early improvement and plasma levels of key metabolites and ECTP are predictive of therapeutic treatment outcomes and thus can be used to guide the use of ECTP.

著者

Yoshio Takahata Misato Hara Kouhei Nishino Takao Kawakami

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0122, 2023-05-24 (Released:2023-05-24)

参考文献数

26

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Immuno-mass spectrometry (MS) is a powerful method for the quantitative analysis of low-abundance proteins in biological specimens. In these procedures, collecting specifically and efficiently the target protein antigens from the antigen–antibody complex generated on the surface of nanocarrier beads is crucial and can be performed by hydrolyzing the proteins directly on the beads or after elution. Herein, we optimized the conditions of the immunoaffinity purification via elution using serum α-fetoprotein (AFP) as a model and its specific antibody immobilized covalently on magnetic beads. Antibody-coated beads were incubated with human serum spiked with standard AFP for antigen–antibody reaction. AFP was then eluted from the beads using various eluents, including organic solvents, to optimize the elution conditions. After proteolytically hydrolyzing the eluted protein, stable isotope-labeled standard peptides were added to the hydrolysate to quantify the eluted AFP via liquid chromatography–tandem MS. Using an optimized workflow for quantitative analysis afforded a correlation between the amount of spiked AFP and heavy to light ratios calculated based on peptide ion peak areas, from which an endogenous AFP concentration of 2.3±0.6 ng/mL was determined in normal serum; this is consistent with previous reports using radioimmunoassay methods. The present immuno-MS workflow could apply to the detection and quantitation of other low-abundance biofluid biomarkers.

著者

Yamato Miyazaki Atsushi Yamamoto

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0119, 2023-04-06 (Released:2023-04-06)

参考文献数

9

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To evaluate the safety of food for pets, the migration of chemical substances from pet tableware was investigated by mass spectrometry. The presence of polymer additives Irgafos 168 and Erucamide were suspected based on mass spectra and were confirmed to be present in polypropylene tableware. The amount of substances migrated using simulated saliva was examined by liquid chromatography-mass spectrometry after solid phase extraction and purification. Photoionization was found to be suitable for the simultaneous determination of these substances. The detection limits of the established method were 0.019 μg/mL for Irgafos 168 and 0.022 μg/mL for Erucamide. Five different types of pet tableware purchased in local markets were examined and no analytes were detected in the simulated saliva using shaking extraction. In this study, the risk to pets from the substances migrated from pet tableware was considered to be sufficiently low.

著者

Takafumi Hirata Menghao Yang Hui Hsin Khoo

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0121, 2023-05-11 (Released:2023-05-11)

参考文献数

31

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In situ and rapid analysis of organic compounds using a combination of a newly-developed laser ablation in liquid (LAL) sampling technique combined with electrospray ionisation mass spectrometry (ESI-MS) is reported. The LAL is a technique that allows laser ablation to be conducted in a liquid medium containing organic compounds that were effectively extracted from solid materials into the liquid medium. Three organic compounds (valine, caffeine, and benzyl butyl phthalate (BBP)) were subjected to analysis. The LAL sampling was conducted in the fast-laser scanning mode using Galvanometric optics, and the total ablation time required for the sampling from a 1 mm2 area was about 3 s, thus providing rapid sampling. The resulting sample solution was directly introduced into the ESI-MS system, without the need for any chromatographic separation. To evaluate the analytical capability of the LAL technique coupled with ESI-MS, both the overall transmission efficiencies of analytes from solid materials to the ion detector, and the repeatabilities of the measurements were rigorously tested. This involved the use of synthetic, in-house prepared standard materials containing the analytes. The overall ion yields were about 1.1×10−3% for valine, 8.7×10−3% for caffeine, and 6.7×10−4% for BBP. By comparing the ion yields obtained by the injection of an analyte solution and a standard solution through the mass spectrometer, the recoveries through the LAL sampling were approximately 31% for valine, 45% for caffeine, and 37% for BBP. In addition, the analytical repeatabilities for all analytes were better than 6%. The analytical repeatabilities were mainly affected by either the heterogeneity of the in-house standard materials or changes in the plasma temperature by coexisting, laser-induced sample particles. It should be noted that not only water-soluble compounds (caffeine and valine), but also non-soluble compound (BBP) could be measured by the LAL-ESI-MS, which is one of the great advantages over the conventional liquid extraction surface analysis technique. The data obtained here clearly demonstrate that the LAL-ESI-MS has the potential for being a fast and user-friendly analytical technique for the in-situ detection for both the water-soluble and water-insoluble molecules.

著者

Ayumi Kubo Azusa Kubota Haruki Ishioka Takuhiro Hizume Masaaki Ubukata Kenji Nagatomo Takaya Satoh Mitsuyoshi Yoshida Fuminori Uematsu

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0120, 2023-04-13 (Released:2023-04-13)

参考文献数

15

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Electron ionization (EI) mass spectrum library searching is usually performed to identify a compound in gas chromatography/mass spectrometry. However, compounds whose EI mass spectra are registered in the library are still limited compared to the popular compound databases. This means that there are compounds that cannot be identified by conventional library searching but also may result in false positives. In this report, we report on the development of a machine learning model, which was trained using chemical formulae and EI mass spectra, that can predict the EI mass spectrum from the chemical structure. It allowed us to create a predicted EI mass spectrum database with predicted EI mass spectra for 100 million compounds in PubChem. We also propose a method for improving library searching time and accuracy that includes an extensive mass spectrum library.

著者

Kenzo Hiraoka Yuji Sakai Hiroyuki Kubota Satoshi Ninomiya Stephanie Rankin-Turner

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0114, 2023-01-31 (Released:2023-01-31)

参考文献数

35

被引用文献数

1

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Among the various types of cluster secondary ion mass spectrometry (SIMS), electrospray droplet impact/secondary ion mass spectrometry (EDI/SIMS) is unique due to its high ionization efficiency and non-selective atomic/molecular-level surface etching ability. In this study, EDI/SIMS was applied to the non-selective etching of synthetic polymers of polystyrene (PS) and poly(9,9-di-n-octylfluonyl-2,7diyl) (PFO) deposited on a silicon substrate. The polymers gave characteristic fragment ions and the mass spectra remained unchanged with prolonged EDI irradiation time, indicating that non-selective etching can be achieved by EDI irradiation, a finding that is consistent with our previous reports based on EDI/X-ray photoelectron spectroscopy analyses. From the irradiation time and film thickness, the etching rates for PS and PFO were roughly estimated to be 0.6 nm/min and 0.15 nm/min, respectively, under the experimental conditions that were used. After the depletion of polymer sample on the surface, ion signals originating from the exposed silicon substrate were observed. This indicates that EDI/SIMS is applicable to the analysis of the interface of multilayered films composed of organic and inorganic materials.

著者

Narumi Moromoto Yosuke Kawai Kentaro Terada Masaaki Miyahara Naoto Takahata Yuji Sano Naoko Fujikawa Mahesh Anand

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.12, no.1, pp.A0115, 2023-02-10 (Released:2023-02-10)

参考文献数

41

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Northwest Africa (NWA) 2977 is a lunar basaltic meteorite that was found in 2005 and has been classified as an olivine cumulate gabbro. This meteorite contains a shock melt vein (SMV) induced by an intense shock event. We report herein on an in-situ analysis of phosphates in the host gabbro and the shock vein for the U–Pb dating of NWA 2977 using an ion microprobe, NanoSIMS. The majority of the analyzed phosphates, in both the SMV and host-rock, lie on a linear regression in 238U/206Pb–207Pb/206Pb–204Pb/206Pb three-dimensional space, indicating a total Pb/U isochron age of 3.15±0.12 Ga (95% confidence level), which is consistent ages determined in previous isotopic studies of NWA 2977 (Sm–Nd age of 3.10±0.05 Ga, Rb–Sr age of 3.29±0.11 Ga, and Pb–Pb baddeleyite age of 3.12±0.01 Ga), and identical to the age of the U–Pb phosphate in a paired meteorite NWA 773, 3.09±0.20 Ga, derived from our dataset. There was no clear difference in the formation age between the phosphates found in the SMV and host-rock, although the shape and size of the grains and the Raman spectra show the evidence of intense shock metamorphism. Based on these findings, the cooling rate of the phosphate was very rapid, constrained to be larger than 140 K/s.

著者

Fumio Matsuda Shuka Komori Yuki Yamada Daiki Hara Nobuyuki Okahashi

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.11, no.1, pp.A0106, 2022-12-15 (Released:2022-12-15)

参考文献数

44

被引用文献数

1

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In metabolomics studies using high-resolution mass spectrometry (MS), a set of product ion spectra is comprehensively acquired from observed ions using the data-dependent acquisition (DDA) mode of various tandem MS. However, especially for low-intensity signals, it is sometimes difficult to distinguish artifact signals from true fragment ions derived from a precursor ion. Inadequate precision in the measured m/z value is also one of the bottlenecks to narrowing down the candidate compositional formula. In this study, we report that averaging multiple product ion spectra can improve m/z precision as well as the reliability of fragment ions that are observed in such spectra. A graph-based method was applied to cluster a set of similar spectra from multiple DDA data files resulting in creating an averaged product-ion spectrum. The error levels for the m/z values declined following the central limit theorem, which allowed us to reduce the number of candidate compositional formulas. The improved reliability and precision of the averaged spectra will contribute to a more efficient annotation of product ion spectral data.

著者

Yumi Miyake Sachie Kusaka Isao Murata Michisato Toyoda

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.11, no.1, pp.A0105, 2022-12-20 (Released:2022-12-20)

参考文献数

29

被引用文献数

1 2

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Boron neutron capture therapy (BNCT) is a cell-selective particle therapy for cancer using boron containing drugs. Boron compounds are accumulated in high concentration of tens ppm level of boron in target tumors to cause lethal damage to tumor tissue. The examination of boron distribution in target tumor and normal tissue is important to evaluate the efficiency of therapy. The matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) is a powerful tool to visualize the distribution of target analyte in biological samples. In this manuscript, we report a trial to visualize the distribution of a typical BNCT drug, L-4-phenylalanine boronic acid (BPA) in a brain tumor model rat using MALDI-MSI technique. We performed a MALDI-MSI with high mass resolution targeting to [BPA+H]+ at m/z 210 in a BPA-treated rat brain section using a spiral orbit-type time of flight (SpiralTOF) mass spectrometer. Several BPA ion species, [BPA+H]+, [BPA−H2O+Na]+, [BPA+DHB−2H2O+Na]+ and [BPA+DHB−2H2O+K]+ were detected separate from peaks originated from biomolecules or matrix reagent by achieving the mass resolving power of approximately 20,000 (full width at half maximum; FWHM) at m/z 210. The mass images with 60 μm spatial resolution obtained from these BPA ion species in a mass window of 0.02 Da revealed their localization in the tumor region. Additionally, the mass image obtained from [BPA+H]+ also likely showed the distribution of BPA inside the tumor. MALDI-MSI with high mass resolution targeting to [BPA+H]+ has a great potential to visualize the distribution of BPA in brain tissue with tumor.

著者

Yoshinao Wada Machiko Kadoya Nobuhiko Okamoto

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.11, no.1, pp.A0113, 2022-12-28 (Released:2022-12-28)

参考文献数

21

被引用文献数

1

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Dried blood spot (DBS) is the standard specimen for the newborn screening of inborn errors of metabolism (IEM) by tandem mass spectrometry. Availability of DBS for the mass spectrometric analysis of the diagnostic marker proteins, transferrin (Tf) and apolipoprotein CIII (apoCIII), of congenital disorders of glycosylation (CDG) was examined. Recovery of Tf from DBS was only slightly reduced compared with fresh serum. Although oxidation of the core polypeptides was observed, glycans of Tf and apoCIII were unaffected by storage of DBS in the ambient environment for at least 1 month. The combination of DBS and the triple quadrupole mass spectrometer used for IEM screening was sufficient to characterize the aberrant glycoprofiles of Tf and apoCIII in CDG. DBS or dried serum spot on filter paper can reduce the cost of sample transportation and potentially promote mass spectrometric screening of CDG.