著者

Sayaka Nakamura Hiroaki Sato Thierry N. J. Fouquet

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.9, no.1, pp.A0079, 2020-02-06 (Released:2020-02-06)

参考文献数

18

被引用文献数

2

---

The Kendrick analysis is used for the processing and visualization of mass spectra obtained from polymers containing C, H, O and/or Si with simple isotopic patterns (monoisotope=lightest isotope=most intense isotope for short chains). In the case of heteroatoms with complex isotopic patterns, the impact of the chosen isotope on point alignments in Kendrick plots has not been examined extensively. Rich isotopic patterns also make the evaluation of the mass and nature of the repeating unit and end-groups more difficult from the mass spectrum in the case of unknown samples due to the number of peaks and the absence of a monoisotopic peak. Using a polybrominated polycarbonate as running example, we report that horizontal point alignments can be obtained in a Kendrick plot using the mass of the most abundant isotope instead of the monoisotopic mass as is usually done. Rotating the plot (“reverse Kendrick analysis”) helps to accurately evaluate the mass of the most abundant isotope of the repeating unit, as well as the nature of the brominated neutral expelled upon gentle heating (debromination or dehydrobromination). The whole procedure is then applied to the characterization of an unknown polybrominated flame retardant in an industrial formulation before and after heating.

著者

Lee Chuin Chen

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.8, no.2, pp.S0079, 2019-08-26 (Released:2019-08-26)

参考文献数

87

被引用文献数

7

---

Increasing the operating temperature of the liquid chromatography (LC) column has the same effect as reducing the diameter of the packing particles on minimizing the contribution of C-term in the van Deemter equation, flattening the curve of plate height vs. linear velocity in the high-speed region, thus allowing a fast LC analysis without the loss of plate count. While the use of smaller particles requires a higher pumping pressure, operating the column at higher temperature reduces the pressure due to lower liquid viscosity. At present, the adoption of high-temperature LC lags behind the ultra-high-pressure LC. Nevertheless, the availability of thermally stable columns has steadily improved and new innovations in this area have continued to emerge. This paper gives a brief review and updates on the recent advances in high-temperature liquid chromatography (HTLC). Recent efforts of hyphenating the capillary HTLC with mass spectrometry via a super-atmospheric pressure electrospray ionization is also reported.

著者

Ami Kageyama (Kaneshima) Akira Motoyama Mitsuo Takayama

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.8, no.1, pp.A0077, 2019-11-30 (Released:2019-11-30)

参考文献数

24

被引用文献数

7

---

The influence of solvent composition and surface tension on the signal intensity of deprotonated molecules [M−H]− in electrospray ionization mass spectrometry (ESI MS) was evaluated using alanine (Ala), threonine (Thr) and phenylalanine (Phe), which have differing levels of hydrophobicity. The surface tension of the ESI solution was varied by changing the ratio of the organic solvents methanol (MeOH) and acetonitrile (MeCN) in water (H2O). In ESI MS, the signal intensity of all the amino acids was increased with decreasing surface tension for the two solutions, H2O/MeOH and H2O/MeCN. The use of H2O/MeCN was more favorable for achieving a strong signal for the analytes compared to H2O/MeOH. The smaller vaporization enthalpy of MeCN compared to MeOH was proposed as one of the most plausible explanation for this. The order of the signal intensity of amino acids was Phe>Thr>Ala, the same order as their hydrophobicity. It can be practically concluded that the use of solutions with lower surface tensions and lower vaporization enthalpies would result in higher signal intensities in ESI MS.

著者

Hisao Nakata

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.8, no.1, pp.A0074, 2019-11-25 (Released:2019-11-25)

参考文献数

46

被引用文献数

4

---

Typical modes of bond cleavages of organic compounds in mass spectrometry are briefly summarized. Although these fragmentation rules can be quite useful for interpreting mass spectra of simple compounds, application to structurally complex molecules that contain multiple hetero atoms such as nitrogen or oxygen becomes increasingly difficult, because the exact location of an unpaired electron or positive or negative charges becomes obscure in precursor ions.About a decade ago, we proposed “a rule of mass shift,” which correctly predicts the m/z for observed peaks corresponding to singly charged even-electron fragment ions. The basis of the rule postulates that ions observed as peaks in an ordinary mass spectrum should be sufficiently stable to survive during the flight path in a mass spectrometer.The important recognition is that each atom in a stable ion should be in an ordinary valence state, and no free valence should be allowed. Therefore, if the cleavage of a bond leads to an ion with an unstable structure, some structural changes must take place in order for the ion to be observed in the mass spectrum. Such structural changes can be the addition of hydrogen atom(s) and/or a proton for positive ions, and the addition of a hydrogen atom and/or the elimination of two hydrogen atoms in the case of negative ions. These required structural changes in each case are schematically depicted and discussed in detail.Two typical examples are shown, in which m/z’s of the observed peaks are correctly predicted. The scope and limitations, as well as the significance of the rule for analyzing fragmentations in organic mass spectrometry are also discussed.

著者

Nobuyuki Okahashi Shuichi Kawana Junko Iida Hiroshi Shimizu Fumio Matsuda

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.8, no.1, pp.A0073, 2019-08-30 (Released:2019-08-30)

参考文献数

15

被引用文献数

1 18

---

Isotope labeling measurements using mass spectrometry can provide informative insights on the metabolic systems of various organisms. The detailed identification of carbon positions included in the fragment ions of dicarboxylic and tricarboxylic acids in central carbon metabolism is needed for precise interpretation of the metabolic states. In this study, fragment ions containing the carbon backbone cleavage of dicarboxylic and tricarboxylic in the Krebs cycle were investigated by using gas chromatography (GC)-electron ionization (EI)-MS and GC-EI-MS/MS. The positions of decarboxylation in the dicarboxylic and tricarboxylic acids were successfully identified by analyses using position-specific 13C-labeled standards prepared by in vitro enzymatic reactions. For example, carboxyl groups of C1 and C6 of trimethylsilyl (TMS)- and tert-butyldimethylsilyl (TBDMS)-derivatized malic and citric acids were primarily cleaved by EI. MS/MS analyses were also performed, and fragment ions of TBDMS-citric and α-ketoglutaric acids (αKG) with the loss of two carboxyl groups in collision-induced dissociation (CID) were observed.

著者

Kanako Sekimoto Motoshi Sakakura Hiroshi Hike Takatomo Kawamukai Teruhisa Shiota Mitsuo Takayama

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.8, no.1, pp.A0075, 2019-10-25 (Released:2019-10-25)

参考文献数

36

被引用文献数

1

---

Herein, a dark-current discharge state created by combining argon flow with a needle electrode in ambient air is described that has an ionization efficiency and mechanism comparable to those of conventional helium direct analysis in real time (DART), without requiring dopants and DART glow discharge. Using this method, polar compounds such as α-amino acids were ionized in the dark-current argon discharge via (de)protonation, molecular anion formation, fragmentation, (de)protonation with the attachment of oxygen, deprotonation with hydrogen loss and negative ion attachment. In contrast, nonpolar compounds (e.g., n-alkanes) were detected as positive ions via hydride abstraction and oxidation. Major background ions observed were H3O+(H2O)n, O2·+, O2·−(H2O)n and CO3·−. These results indicate that the present dark-current discharge efficiently generates resonance-state argon with an internal energy of ∼14.2 eV, higher than that of the well-known metastable state (∼11.6 eV). It is therefore suggested that ionization reactions occurring there can be attributed to the Penning ionization of atmospheric H2O and O2 by resonance-state argon, analogous to helium DART.

著者

Bui Kamihoriuchi Yoichi Otsuka Aya Takeuchi Futoshi Iwata Takuya Matsumoto

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.7, no.2, pp.S0078, 2019-03-06 (Released:2019-03-07)

参考文献数

22

被引用文献数

1 7

---

Ambient sampling and ionization techniques based on direct liquid extraction and electrospray ionization are of great value for rapid analysis and mass spectrometry imaging. Scanning probe electrospray ionization (SPESI) enables the sampling and ionization of analyte molecules in a solid material using a liquid bridge and electrospray, respectively, from a single capillary probe. To further improve SPESI, it is essential to understand the dynamic behavior of nanoliter volumes of liquids during sampling and ionization. In this study, the dynamic formation and breakage of the liquid bridge and the subsequent electrospray ionization were investigated by measuring the displacement of the capillary probe using a new optical technique. Measurements revealed that both the time from the formation of the liquid bridge to its breakage and the time from the breakage of the liquid bridge to the detection of analyte ions were correlated with the physical properties of the solvent. It was also found that both of these times were positively correlated with the flow rate. These results will not only lead to the improvement of sampling and ionization efficiencies but also afford a greater understanding of the physicochemical properties of charged nanoliter volumes of liquids.

著者

Nobuyuki Okahashi Shuichi Kawana Junko Iida Hiroshi Shimizu Fumio Matsuda

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

pp.A0073, (Released:2019-08-01)

参考文献数

15

被引用文献数

18

---

Isotope labeling measurements using mass spectrometry can provide informative insights on the metabolic systems of various organisms. The detailed identification of carbon positions included in the fragment ions of dicarboxylic and tricarboxylic acids in central carbon metabolism is needed for precise interpretation of the metabolic states. In this study, fragment ions containing the carbon backbone cleavage of dicarboxylic and tricarboxylic in the Krebs cycle were investigated by using gas chromatography (GC)-electron ionization (EI)-MS and GC-EI-MS/MS. The positions of decarboxylation in the dicarboxylic and tricarboxylic acids were successfully identified by analyses using position-specific 13C-labeled standards prepared by in vitro enzymatic reactions. For example, carboxyl groups of C1 and C6 of trimethylsilyl (TMS)- and tert-butyldimethylsilyl (TBDMS)-derivatized malic and citric acids were primarily cleaved by EI. MS/MS analyses were also performed, and fragment ions of TBDMS-citric and α-ketoglutaric acids (αKG) with the loss of two carboxyl groups in collision-induced dissociation (CID) were observed.

著者

佐々木 申二

出版者

The Mass Spectrometry Society of Japan

雑誌

Journal of the Mass Spectrometry Society of Japan (ISSN:13408097)

巻号頁・発行日

vol.1959, no.12, pp.3-3, 1959-03-31 (Released:2010-06-28)

著者

Toshihiro Suzuki Shuhei Sakata Yoshiki Makino Hideyuki Obayashi Seiya Ohara Kentaro Hattori Takafumi Hirata

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.7, no.1, pp.A0065-A0065, 2018-02-23 (Released:2018-03-01)

参考文献数

14

被引用文献数

37

---

We report on the development of a software program named iQuant2 which creates visual images from two-dimensional signal intensity data obtained by a laser ablation-ICP-mass spectrometry (LA-ICPMS) technique. Time-resolved signal intensity profiles can be converted to position resolved signal intensity data based on the rastering rate (μm s−1) of the laser ablation. Background signal intensities obtained without laser ablation (gas blank) are used as the background, and all of the blank-subtracted intensity data can be used for the imaging analysis. With this software, deformation of the created image can be corrected visually on a PC screen. The line profile analysis between the user-selected points can be observed using the iQuant2 software. To accomplish this, data points on the profile line were automatically calculated based on the interpolation between the analysis points. The resulting imaging data can be exported and stored as JPEG, BMP or PNG formats for further processing. Moreover, a semi-quantitative analysis can be made based on the coupling of the external correction of the RSF (relative sensitivity factor) using NIST SRM610 with normalization of the corrected signal intensity data being 100%. The calculated abundance data for major elements are in reasonable agreement with the values obtained by electron probe micro analyzer (EPMA). With the software developed in this study, both the rapid imaging and semi-quantitative determinations can be made.

著者

Chi-Wei Lee Hung Su You-Da Cai Ming-Tsang Wu Den-Chyang Wu Jentaie Shiea

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.6, no.2, pp.S0056-S0056, 2017-03-31 (Released:2017-03-28)

参考文献数

18

被引用文献数

2 20

---

Psychoactive drug overdoses are life-threatening and require prompt and proper treatment in the emergency room to minimize morbidity and mortality. Prompt identification of the ingested psychoactive drugs is challenging, since witness recall is unreliable and patients’ symptoms do not necessarily explain their loss of consciousness. Gas and liquid chromatography mass spectrometric analyses have been the traditionally employed methods to detect and identify abused substances; however, these techniques are time-consuming and labor-intensive. In this study, thermal desorption electrospray ionization mass spectrometry, an ambient mass spectrometric technique, was applied to rapidly characterize flunitrazepam, lysergic acid diethylamide, and 3,4-methylenedioxy-methamphetamine in drained gastric lavage fluid, and ketamine, cocaine, amphetamine and norketamine in whole blood samples. No pretreatment of the gastric lavage fluid specimens was required and the entire analytical process took less than 30 s per specimen. Liquid–liquid extraction, followed by centrifugation, was performed on the whole blood samples. The corresponding compounds were identified through matching the obtained mass spectrometric data with those provided by commercial databases. The limits-of-detection of the tested drugs in both drained gastric lavage fluid and whole blood samples are at sub ppm levels. This is sensitive enough for emergency medical application, since the quantities of medications ingested by overdosed abusers are much higher than the amounts that were tested.

著者

土屋 正彦 堀井 雄二

出版者

The Mass Spectrometry Society of Japan

雑誌

Journal of the Mass Spectrometry Society of Japan (ISSN:13408097)

巻号頁・発行日

vol.22, no.1, pp.79-85, 1974

被引用文献数

4

---

Mass spectra of excess-kinetic-energy ions(KE ions)formed under electron impact have been studied by using a commercial mass spectrometer with the modified ion source. Parent ions of KE ions may be so much excited than those of thermal-energy ions that they may decompose more quickly and give much simple cleavage ions and less rearrangement ions. Therefore the mass spectrum of KE ions must be different from the ordinary mass spectrum. Several compounds of alcohols and ethers have been studied. Simple relations have been found between the mass spectra of KE ions and the structure of these compounds. Generally, fragment ions which are smaller than a half of a molecule can be observed as KE ions and the terminal groups of a compound, such as CH3CO, -CH2OH, HCO-, C2H5-and so on, give the intense peaks. It has been proved that the mass spectra of KE ions show less rearrangement and are useful for the structure determination of organic compounds

著者

吉野 健一

出版者

The Mass Spectrometry Society of Japan

雑誌

質量分析 = Mass spectroscopy (ISSN:13408097)

巻号頁・発行日

vol.56, no.6, pp.269-274, 2008-12-01

被引用文献数

1

---

The unified atomic mass unit (unit symbol: u) is a non-SI unit of mass, defined as one-twelfth the mass of a single ¹²C atom in its ground state. [SI: Le Système International d'Unités; The International System of Units] This definition was agreed upon by both the International Union of Pure and Applied Physics (IUPAP) and the International Union of Pure and Applied Chemistry (IUPAC) in the early 1960s to resolve a longstanding difference between two scales of the atomic mass unit. The term "atomic mass unit" (unit symbol: amu) has been used as a unit of mass defined as one-sixteenth the mass of a single atom ¹⁶O [<i>m</i>(¹⁶O)=16 amu] in physics and as one-sixteenth the isotope-averaged atomic mass (equivalent to the atomic weight) of oxygen [<i>A</i>_r(O)=16 amu] in chemistry.<br>The unit dalton (unit symbol: Da) is also a non-SI unit of mass defined as "1 Da=1 u," and is accepted as a unit for use by the SI in the 8th edition of the SI brochure (2006). Therefore, both the unified atomic mass unit and dalton are authorized units for mass of ions and molecules. <br>It is a common mistake to use the deprecated term "atomic mass unit" and the deprecated unit symbol "amu" for the unit of mass defined as one-twelfth the mass of single atom ¹²C. The unit symbol "mmu," meaning a millimass unit, is also an appropriate unit in SI. Instead of "mmu," "mDa" or and "10^-3 u" should be used.

著者

Hiroaki Sato Yoko Ishii Hikaru Momose Takafumi Sato Kanae Teramoto

出版者

The Mass Spectrometry Society of Japan

雑誌

Mass Spectrometry (ISSN:2187137X)

巻号頁・発行日

vol.2, no.1, pp.A0014, 2013-02-01 (Released:2013-01-31)

参考文献数

22

被引用文献数

10 13

---

The structural characterization of copolymers by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) remains a challenging task, since their random comonomer distribution creates very complicated mass spectra. In this study, a high-resolution TOF mass spectrometer with a spiral ion trajectory was applied to the structural and compositional characterization of free radical copolymerized poly(methyl methacrylate-co-tert-butyl methacrylate), poly(MMA-co-tBMA)s in ethyl lactate acting as a chain transfer agent. Virtually complete peak assignments of the isobaric components within the poly(MMA-co-tBMA)s served to identify the end-group combinations and copolymer compositions of individual copolymer components, allowing the distributions of comonomer compositions and six types of end-group combinations to be evaluated.

著者

渋江 俊道 ウォン カイティ グロス マイケル

出版者

The Mass Spectrometry Society of Japan

雑誌

質量分析 = Mass spectroscopy (ISSN:13408097)

巻号頁・発行日

vol.48, no.3, pp.221-227, 2000-06-01

参考文献数

20

被引用文献数

3

---

We developed an assay method that utilizes ESI and ion trap mass spectrometry to rapidly determine the binding nature of drugs with oligodeoxynucleotides and to assess their relative affinities, stoichiometries and specificities in non-covalent interactions. Selectivity experiments show that the drugs H₂TMpyP and CuTMpyP bind <I>via</I> mixed modes, whereasFeTMpyP and MnTMpyP interact by groove binding only. Competitive binding experiments show that the order for the drugs with duplex 5′ATATAT3′ was H₂TMpyP-CuTMpyP>FeTMpyP-MnTMpyP. We also investigated the gas-phase stability of duplex oligodeoxynucleotides and the non-covalent complexes by monitoring the dissociation profiles of those non-covalent associations as a function of collision energy in the ion-trap mass spectrometer. We defined a half-wave collision energy which corresponds to the collision energy (in percentage of the maximum tickling voltage) at which the relative abundance of the complex ion had dropped to 50% and used this as an estimate of the gas-phase stability. The gas-phase stability of double-stranded oligonucleotide correlates with the number of H-bonds within the duplex. The noncovalent complexes of the drugs (Distamycin A, Actinomycin D, and Mn(III)TMpyP) and the duplex oligonucleotides are more stable in the gas phase than the duplexes themselves.

著者

Yoon Boo Ok Koyanagi Shin Asano Takao HARA Mariko HIGUCHI Akon

出版者

The Mass Spectrometry Society of Japan

雑誌

質量分析 = Mass spectroscopy (ISSN:13408097)

巻号頁・発行日

vol.51, no.1, pp.168-173, 2003-02-01

被引用文献数

1 2

---

We undertook a fundamental investigation of the removal of endocrine disruptors from aqueous solution by a sorption method using activated carbons, and compared the removal ability of endocrine disruptors by activated carbons to that by polydimethylsiloxane (PDMS) membranes. The activated carbons exhibited high removal ability of 1,2-dibromo-3-chloropropane (DBCP), 100 fold increased adsorption over that with PDMS membranes from aqueous solution of DBCP. The removal ratio of the endocrine disruptors, <i>e.g., </i>1,2-dibromo-3-chloropropane, dibenzo-<i>p</i>-dioxin, and hexachlorocyclohexane, increased linearly in an aqueous solution with increasing the logarithm of <i>P</i>_ow of the endocrine disruptors. Almost complete removal of the endocrine disruptors (<i>i.e.,</i>>85%) was observed above log <i>P</i>_ow=3.5 in 25 mL of an aqueous solution using 0.05 g activated carbon. One aim of the present study is to use preferential sorption of chemical contaminants onto activated carbons for removal of the chemical contaminants from aqueous solutions including drinking water, beverages, milk, and human milk. When the removal of endocrine disruptors contained in milk or human milk is targeted, water soluble vitamins in the milk, such as vitamin B₂, vitamin B₁₂, and niacin are expected to be co-currently adsorbed on the activated carbons. Therefore, the present sorption method using activated carbon was applied to the removal of endocrine disruptors, such as di-<i>n</i>-octylphthalate, from the mineral water and 89% of di-<i>n</i>-octylphthalate was removed.

著者

長友 健治

出版者

The Mass Spectrometry Society of Japan

雑誌

質量分析 = Mass spectroscopy (ISSN:13408097)

巻号頁・発行日

vol.54, no.5, pp.194-195, 2006-10-01

被引用文献数

1