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

高岡 宣雄

出版者

日本質量分析学会

雑誌

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

巻号頁・発行日

vol.37, no.6, pp.343-351, 1989 (Released:2007-05-01)

被引用文献数

14 10

---

The assumption that the 40Ar/36Ar ratio of Ar trapped in volcanic rocks at eruption is atmospheric often gives a large systematic error in the K-Ar dating of Quaternary volcanic rocks younger than 1 Ma. There are two possible sources of error, the existence of excess Ar and mass-fractionated, initial Ar.The major source of excess Ar is supposed to be magma. The 40Ar/36Ar ratio for magmatic Ar in the North-East Japan arc is tentatively estimated to be 340±10 from measurements of Ar in large phenocrysts separated from Quaternary volcanic rocks. Separation of phenocrysts is the most effective to decrease the systematic error caused by excess Ar.The mass-fractionation of initial Ar should give the 38Ar/36Ar ratio which was changed from the atmospheric ratio. This can be checked by determining the 38Ar/36Ar ratio in samples. A peak-height comparison method is preferential to an isotope dilution method in the K-Ar dating of very young volcanic rocks because with the former, both the amount of Ar and the 38Ar/36Ar ratio in a sample can be determined at one measurement, while with the latter, an additional measurement is needed to know the 38Ar/36Ar ratio in the sample. Further, the statistical error in the isotope dilution method overwhelms that of the peakheight comparison method for large atmospheric Ar correction (e.g., 83% correction for 1% relative errors of isotopic ratio measurements). Since the systematic error caused by the mass-fractionated, initial Ar increases greatly with the increasing atmospheric Ar correction, it is important to correct the result for the mass-fractionation. Correction formulae are given.The error sources other than those mentioned above are uncertainty in the blank correction and instabilities in the sensitivity of spectrometer and the Ar isotopic ratio measurement. Especially, Ar in Al- or other metal foil should be taken into consideration for the blank correction. In order to increase accuracy of the K-Ar age obtained, to check the systematic errors by measuring samples together with standard samples is of great importance in the K-Ar dating of very young volcanic rocks.A measurable limit of K-Ar age is affected greatly by the atmospheric Ar correction. For andesites containing 5×10-11 ccSTP 36Ar/g and 2 wt% K, the limit is estimated to be 0.004 Ma for 98% atmospheric Ar correction. For most of Japanese Quaternary lavas which contain 2×10-10 ccSTP 36Ar/g and 2 wt% K, the limit is 0.015 Ma for the same atmospheric Ar correction.

著者

松本 哲一 宇都 浩三 柴田 賢

出版者

日本質量分析学会

雑誌

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

巻号頁・発行日

vol.37, no.6, pp.353-363, 1989 (Released:2007-05-01)

被引用文献数

11 8

---

Precise determination of argon isotopic ratios was made on twenty-seven historic lavas from Japan. Their isotopic ratios were mostly mass fractionated from that of the atmospheric argon toward the enrichment in lighter isotopes. This suggests that the correction for the mass fractionated initial 40Ar/36Ar ratio is very important for the K-Ar dating of volcanic rocks younger than 0.1 Ma. The limit of measurable K-Ar age is estimated to be 0.03 Ma for a normal andesitic lava having a fractionated initial argon.

著者

杉浦 悠毅

出版者

日本質量分析学会

雑誌

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

巻号頁・発行日

vol.63, no.6, pp.159-162, 2015-12-01 (Released:2015-12-26)

参考文献数

2

著者

田中 耕一

出版者

日本質量分析学会

雑誌

質量分析 = Mass spectroscopy (ISSN:13408097)

巻号頁・発行日

vol.45, no.1, pp.113-121, 1997-02-01

著者

二見 順 入江 浩彰 大江 修造 西 功

出版者

日本質量分析学会

雑誌

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

巻号頁・発行日

vol.47, no.6, pp.386-388, 1999 (Released:2007-10-16)

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In recent studies, it has been revealed that Helicobacter pylori (HP) causes stomach cancer, stomach ulcers, duodenal ulcers and chronic gastritis. The 13C-urea breath test (UBT) is one of the diagnostic methods for HP infection. A new UBT method with the respiratory mass spectrometer developed by authors continuously measures with on-line the amount of decomposed 13C-urea in the stomach after the administration of 13C-urea. Trial examinations by the new method were carried out with two subjects; one was diagnosed positive of HP infection and the other was negative by clinical examinations. Significant difference was found in the amount of decomposed 13C-urea between both subjects. The results presented in this paper demonstrate that the new UBT method is applicable to the clinical use in the diagnosis of HP infection.

著者

井上 清 小林 唯男 谷口 薫

出版者

日本質量分析学会

雑誌

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

巻号頁・発行日

vol.14, no.5, pp.265-274, 1966-12-25 (Released:2010-06-28)

参考文献数

4

---

A fundamental study was performed on the mass spectrometric determination of the ratios of uranium and fission products in the uranium dioxide specimen irradiated in the nuclear reactor. Mass spectrometer used in this experiment was a 90° sector type with a 350 mm radius of curvature, made by Hitachi, Ltd. In the period of the experiment, this spectrometer was equipped with a thermal-ionization source. The specimen dissolved in nitric acid was pipetted and evaporated to dryness on a filament, and then was analysed in the single filament arrangement. From the results it has been found that: (1)By isotopic analysis of uranium, the contribution to burnup of the specimen by fission of U235was determined as 4, 370 MWD/T. The loss of U235in neutron capture reaction during inadiation was corrected by the ratio of U236to U235. (2)The burnup of the specimen can be determined from the amount of a fission product formed during irradiation. Because of known contribution of the burnup by fission of U235mentioned above, the contribution of burnup of the specimen by fission of Pu239 might be determined by excessive formation of fission product. As the number of fissions of Pu239 was estimated, the burnup of the specimen was calculated as approximately 7, 980 MWD/T. (3)Experience with the mass spectrometric analysis was obtained for the radioactive specimen. The noticeable phenomenon was the increase in the emissivity of ion current at relatively law heating current through filament under the existence of beta-rays emitter.

著者

佐々木 申二

出版者

日本質量分析学会

雑誌

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

巻号頁・発行日

vol.1953, no.1, pp.1-7, 1953 (Released:2010-06-28)

被引用文献数

1

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

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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

久田 美貴

出版者

日本質量分析学会

雑誌

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

巻号頁・発行日

vol.51, no.1, pp.310-316, 2003 (Released:2007-10-16)

参考文献数

14

被引用文献数

1 2

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We examined the applicability of the “nested” collision induced dissociation/post-source decay (CID/PSD) method to sequencing of novel peptides from solitary wasps which have neurotoxic venom for paralyzing other insects. The CID/PSD spectrum of a ladder peptide derived from an exopeptidase digest was compared with that of the intact peptide. The mass peaks observed only in the CID/PSD spectrum of a ladder peptide were extracted as C-terminal fragment ions. Assignment of C-terminal fragment ions enabled calculation of N-terminal fragment masses, leading to differentiation between N-terminal fragment ions and internal fragment ions. Furthermore, a method incorporating nested CID/PSD combined with endopeptidase digestion is described as an approach to determine the sequence of N-terminally modified peptides. The information from immonium and related ions observed in the CID/PSD spectrum was used for the selection of a suitable endopeptidase for the digestion of peptides. These nested CID/PSD methods allowed rapid and sensitive identification by removing ambiguity in the assignment of the fragment ions, and proved useful for sequencing unknown peptides, in particular those available as natural products with a limited supply.

著者

向坂 真一 寺本 華奈江 小池 英樹

出版者

一般社団法人 日本質量分析学会

雑誌

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

巻号頁・発行日

pp.1202230021, (Released:2012-02-27)

参考文献数

18

---

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is widely used for analysis of not only biological materials but also synthetic polymers. A mass spectrum obtained by MALDI-MS was found to have peaks at equal intervals on the m/z axis. The chemical structure of many types of biological compounds contain repeating units that have exactly the same elemental composition. If these repeated peaks could be identified based on the m/z interval value, such analyses could be optimized even further from the point of view of chemical structure. In this study, we describe a system for visualizing such data that has the capability of analyzing the repeated peaks on the m/z axis. The system, mzRepeat, was developed and evaluated by applying the mass spectrum of polyethylene glycol and mycolic acid, which was obtained using a JMS-S3000 Spiral-TOFMS system. Because mzRepeat can systematically show a mass spectrum that includes different numbers of repeating units, it has the potential for use in anlalyzing these types of molecules.

著者

能田 成 村崎 充弘 巽 好幸

出版者

一般社団法人 日本質量分析学会

雑誌

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

巻号頁・発行日

vol.38, no.3, pp.125-131, 1990 (Released:2007-05-01)

被引用文献数

1 1

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Isotopic compositions of Sr and Nd were determined for the volcanic rocks from the Izu Islands Arc. The volcanic rocks from the volcanic front zone show variable Nd isotopes ranging from 0.513088 to 0.513125 of 143Nd/144Nd with an average εNd of 9.0±0.3, and 87Sr/86Sr from 0.70318 to 0.70355 with an average εSr of -16.1±0.7. The back arc side volcanics show slightly lower Nd and Sr isotopic ratios as 143Nd/144Nd from 0.512994 to 0.513066 with an average εNd of 7.8±0.4 and 87Sr/86Sr form 0.70299 to 0.70325 with average εSr of -19.9±0.4. Across arc isotopic variation of Sr and Nd from the volcanic front to the back-arc side is attributed to difference in the degree that the magmas of the subduction zones are generated by the addition of the fluid which is extracted from the hydrous minerals in the down-going slab. Magmas in the volcanic front are much more affected by the addition of the considerable amount of the fluid than the back-arc side magmas and altered Sr and Nd isotopic compositions from their original values of the mantle wedge. The role of the fluid from the down-going slab for magma generation is isotopically assessed in the intra-oceanic Izu arc, and the Nd and Sr isotopic compositions of the fluid extracted from the down-going slab is equivalent with those of the altered MORB.

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

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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

著者

吉野 健一

出版者

一般社団法人 日本質量分析学会

雑誌

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

巻号頁・発行日

vol.56, no.6, pp.269-274, 2008-12-01 (Released:2008-12-15)

参考文献数

7

被引用文献数

1 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 [m(16O)=16 amu] in physics and as one-sixteenth the isotope-averaged atomic mass (equivalent to the atomic weight) of oxygen [Ar(O)=16 amu] in chemistry.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. 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.