Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

コンパクトで高繰り返しのフェムト秒レーザーイオン化源と組み合わせて使用​​するための小型飛行時間型質量分析計

DOI： 10.1016/j.aca.2022.339673

Repository Public URL： https://hdl.handle.net/2324/7153236

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

フェムト秒レーザーイオン化質量分析を使用したアミン関連向精神薬の類似体の包括的な分析

DOI： 10.1021/jasms.1c00282

Repository Public URL： https://hdl.handle.net/2324/7153250

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

レーザーイオン化質量分析と組み合わせたガスクロマトグラフィーのためのブロモメチル芳香族化合物とパーフルオロカルボン酸のエステル化

DOI： 10.1016/j.chroma.2021.462546

Repository Public URL： https://hdl.handle.net/2324/7153237

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

クロマトグラフ法を用いたフェムト秒イオン化質量分光に関する研究を行った。

DOI： 10.1016/j.chroma.2021.462023

Repository Public URL： https://hdl.handle.net/2324/7153248

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

質量分析において、フラグメント化を抑制させることは重要である。シスとトランスの4-メチルシクロヘキサノールに対して可変紫外と近赤外フェムト秒レーザー（35 fs）をイオン化光源として用いる研究を行った。

DOI： 10.1021/acs.analchem.0c03615

Repository Public URL： https://hdl.handle.net/2324/7153235

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

Single Photon Ionization Mass spectrometry Using a Vacuum Ultraviolet Femtosecond Laser

DOI： 10.1021/jasms.0c00154

Repository Public URL： https://hdl.handle.net/2324/7153254

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society for Analytical Chemistry  

時間相関単一イオン計数質量分析計とその性能評価に関する研究を行った。

DOI： 10.2116/analsci.19SBP03

Repository Public URL： https://hdl.handle.net/2324/7153239

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

近赤外領域で最短の光パルスを発生させ、質量分析計のイオン化光源へ応用した成果を発表した。

DOI： 10.1021/acs.analchem.0c00542

Repository Public URL： https://hdl.handle.net/2324/7153238

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry  

Resonant and non-resonant femtosecond ionization mass spectrometry of organochlorine pesticides

DOI： 10.1039/c9an01861a

Repository Public URL： https://hdl.handle.net/2324/2794914

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

Determination of nerve agent metabolites in human urine by femtosecond laser ionization mass spectrometry using 2-(bromomethyl)naphthalene as a derivatizing reagent

DOI： 10.1016/j.aca.2019.04.0120

Repository Public URL： https://hdl.handle.net/2324/2800475

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

A standard sample mixture containing 51 pesticides was separated by gas chromatography (GC), and the constituents were identified by mass spectrometry (MS) using femtosecond lasers emitting at 267, 400, and 800 nm as the ionization source. A two-dimensional display of the GC/MS was successfully used for the determination of these compounds. A molecular ion was observed for 38 of the compounds at 267 nm and for 30 of the compounds at 800 nm, in contrast to 27 among 50 compounds when electron ionization was used. These results suggest that the ultraviolet laser is superior to the near-infrared laser for molecular weight determinations and for a more reliable analysis of these compounds. In order to study the conditions for optimal ionization, the experimental data were examined using the spectral properties (i.e., the excitation and ionization energies and absorption spectra for the neutral and ionized species) obtained by quantum chemical calculations. A few molecules remained unexplained by the currently reported rules, requiring additional rules for developing a full understanding of the femtosecond ionization process. The pesticides in the homogenized matrix obtained from kabosu (citrus sphaerocarpa) were measured using lasers emitting at 267 and 800 nm. The pesticides were clearly separated and measured on the two-dimensional display, especially for the data measured at 267 nm, suggesting that this technique would have potential for use in the practical trace analysis of the pesticides in the environment.

DOI： 10.1021/acs.analchem.8b00537

Repository Public URL： https://hdl.handle.net/2324/7153591

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

The ionization and fragmentation processes were examined for a standard sample mixture containing 16 polycyclic aromatic hydrocarbons (PAHs) and 3 nitro-PAHs (NPAHs) by gas chromatography combined with mass spectrometry (GC/MS) using a femtosecond laser emitting at 400, 800, or 1200 nm as the ionization source. The signal intensities of NPAHs were lower and the fragmentation more extensive compared to those values for PAHs, especially at shorter wavelengths (400 nm). These results can be explained by efficient intersystem crossing to triplet levels and the shorter excited-state lifetimes of neutral NPAHs molecules, compared to the pulse width of the laser. Fragmentation was significantly suppressed by nonresonant multiphoton ionization when a laser emitting at longer wavelengths (1200 nm) was used. This result can be explained by the absorption spectrum of the molecular ion and the excess energy remaining in the ionized state. In fact, there was no absorption band at 1200 nm for the molecular ion, and the excess energy would be minimal when a near-infrared laser is used, which suppresses the fragmentation even for NPAHs. A doubly charged molecular ion was observed for PAHs but not for NPAHs, probably owing to the higher stability of the PAH molecule, the electrons of which are more strongly bound and are more resistive to field ionization. To demonstrate the utility of this technique, the sample extracted from particulate matter 2.5 (PM2.5) emitted from a diesel engine was measured. NPAHs as well as PAHs were clearly determined at 1200 nm, at which the background signal arising from the interference was drastically suppressed.

DOI： 10.1021/acs.analchem.8b00125

Repository Public URL： https://hdl.handle.net/2324/7153590

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

A sample containing nitrated aromatic hydrocarbons (NPAHs) was injected into the sample inlet port of a gas chromatograph (GC), along with hydrazine, a reducing reagent. The analytes that eluted from the GC column were measured by mass spectrometry (MS) using an ultraviolet femtosecond laser as the ionization source. When no reducing reagent was used, large numbers of polycyclic aromatic hydrocarbons (PAHs) including NPAHs were observed in the two-dimensional GC/MS display. In contrast, when hydrazine was present, reduced forms of NPAHs, which included amino PAHs, were detected. When a palladium or platinum catalyst was placed in the GC inlet port, the compounds were further reduced to non-aromatic hydrocarbons. The present approach would be useful for studies to evaluate the chemical reaction that converts the constituents contained in exhaust emitted from a diesel engine. (C) 2017 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.aca.2017.09.049

Repository Public URL： https://hdl.handle.net/2324/7153587

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry  

The ionization and fragmentation processes for pentachlorobenzene were examined using a femto-second laser emitting at 400, 800, and 1200 nm. A molecular ion was clearly observed in the mass spectrum, since the molecule can be directly ionized from the singlet electronic exited state before relaxation to triplet levels, because the pulse width of the laser is shorter than the lifetime of the excited state. Fragmentation was minimal at 1200 nm, in contrast to ionization at 800 and 400 nm. Indeed, a doubly-charged molecular ion was prominent at 800 nm, owing to the absorption band of the singly-charged molecular ion at this wavelength. Fragmentation was further enhanced at 400 nm, which can be explained by the dissociation of the doubly-charged molecular ion having a larger absorption band at 400 nm. Fragmentation was strongly affected by the absorption character of the ionic species, i.e., singly and doubly-charged molecular ions, appeared in the process of multiphoton ionization.

DOI： 10.1039/c7an01172e

Repository Public URL： https://hdl.handle.net/2324/7153586

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

Nerve agent metabolites, i.e., isopropyl methylphosphonic acid (IMPA) and pinacolyl methylphosphonic acid (PMPA), were derivatized by reacting them with 2,3,4,5,6-pentafluorobenzyl bromide (PFBBr) and were determined by mass spectrometry using an ultraviolet femtosecond laser emitting at 267 and 200 nm as the ionization source. The analytes of the derivatized compounds, i.e., IMPA-PFB and PMPA-PFB, contain a large side-chain, and molecular ions are very weak or absent in electron ionization mass spectrometry. The use of ultraviolet femtosecond laser ionization mass spectrometry, however, resulted in the formation of a molecular ion, even for compounds such as these that contain a highly bulky functional group. The signal intensity was larger at 200 nm due to resonance-enhanced two-photon ionization. In contrast, fragmentation was suppressed at 267 nm (nonresonant two-photon ionization) especially for PMPA-PFB, thus resulting in a lower background signal. This favorable result can be explained by the small excess energy in ionization at 267 nm and by the low-frequency vibrational mode of a bulky trimethylpropyl group in PMPA.

DOI： 10.1021/acs.analchem.7b00386

Repository Public URL： https://hdl.handle.net/2324/7165049

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

Structural isomers and enantiomers of hexachlorocyclohexane (HCH) were separated using a chiral column by gas chromatography and quantitatively determined by multiphoton ionization mass spectrometry using an ultraviolet femtosecond laser (200 and 267 nm) as the ionization source. The order of elution of the enantiomers (i.e., (+)-alpha-HCH and (-)-alpha-HCH) was predicted from stabilization energies calculated for the complexes using permethylated gamma-cyclodextrin as the stationary phase of the column, and the results were compared with the experimental data. The molecular ions observed for HCH were weak, even though they can be ionized through a process of resonance enhanced two-photon ionization at 200 nm. This unfavorable result can be attributed to the dissociation of the molecular ion, as predicted from quantum chemical calculations.

DOI： 10.1007/s13361-016-1497-7

Repository Public URL： https://hdl.handle.net/2324/7165079

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

The allergenic compounds listed in the Cosmetics Directive by the Scientific Committee for Consumer Safety were analyzed by gas chromatography combined with multiphoton ionization mass spectrometry using a femtosecond laser emitting at 200 and 267 nm as the ionization source. The limits of detection were less than 100 pg/mu L for all of the compounds, permitting them to be measured in actual samples that were simply prepared by a 100-fold dilution of the original sample. The ionization process was investigated for the 26 allergens, some of which had no absorption band, even in the far-UV region. As a result, nonresonant two-photon ionization was found to be the most sensitive and universal method for the trace analysis of these compounds, because of the short pulse width, i.e., a high peak power, of the femtosecond laser used. It should be noted that the excess energy can be reduced by using a laser emitting at longer wavelengths (267 nm) and that fragmentation can be suppressed, especially for a molecule that contains a long side chain. Three commercially available perfumes were measured, and more than 10 allergenic compounds were determined.

DOI： 10.1021/acs.analchem.6b03229

Repository Public URL： https://hdl.handle.net/2324/7165071

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

Multiphoton ionization processes of parent-polycyclic aromatic hydrocarbons (PPAHs), nitro-PAHs (NPAHs), and amino-PAHs (APAH5) were examined by gas chromatography combined with time-of-flight mass spectrometry using a femtosecond Ti:sapphire laser as the ionization source. The efficiency of multiphoton ionization was examined using lasers emitting in the far-ultraviolet (200 nm), deep ultraviolet (267 nm), and near-ultraviolet (345 nm) regions. The largest signal intensities were obtained when the far-ultraviolet laser was employed. This favorable result can be attributed to the fact that these compounds have the largest molar absorptivities in the far-ultraviolet region. On the other hand, APAH5 were ionized more efficiently than NPAHs in the near-ultraviolet region because of their low ionization energies. A sample extracted from a real particulate matter 2.5 (PM2.5) sample was measured, and numerous signal peaks arising from PAH and its analogs were observed at 200 nm. On the other hand, only a limited number of signed peaks were observed at 345 nm, some of which were signed to PPAHs, NPAHs, and APAHs. Thus, multiphoton ionization mass spectrometry has potential for the use in comprehensive analysis of toxic environmental pollutants. (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.chemosphere.2016.02.114

Repository Public URL： https://hdl.handle.net/2324/7170263

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI  

A simple method was proposed for on-site evaluation of the pulse width of an ultraviolet femtosecond laser coupled with a mass spectrometer. This technique was based on measurement of a two-photon ionization signal in mass spectrometry by translation of the prism in the pulse compressor of the femtosecond laser. The method was applied to optical pulses that were emitted at wavelengths of 267, 241, and 219 nm; the latter two pulses were generated by four-wave Raman mixing using the third harmonic emission of a Ti:sapphire laser (267 nm) in hydrogen gas. The measurement results show that this approach is useful for evaluation of the pulse width of the ultraviolet femtosecond laser used in mass spectrometry for trace analysis of organic compounds.

DOI： 10.3390/app6050136

Repository Public URL： https://hdl.handle.net/2324/7170844

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

Polychlorinated biphenyls (PCBs) in transformer and food oils were measured using gas chromatography combined with multiphoton ionization mass spectroscopy. An ultrashort laser pulse emitting in the far ultraviolet region was utilized for efficient ionization of the analytes. Numerous signal peaks were clearly observed for a standard sample mixture of PCBs when the third and fourth harmonic emissions (267 and 200 nm) of a femtosecond Ti:sapphire laser (800 nm) were employed. The signal intensities were found to be greater when measured at 200 nm compared with those measured at 267 nm, providing lower detection limits especially for highly chlorinated PCBs at shorter wavelengths. After simple pretreatment using disposable columns, PCB congeners were measured and found to be present in the transformer oils used in Vietnam. (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.talanta.2015.11.054

Repository Public URL： https://hdl.handle.net/2324/7170843

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

Particulate matter 2.5 (PM2.5), collected from ambient air in Fukuoka City, was analyzed by gas chromatography combined with multiphoton ionization mass spectrometry using an ultraviolet femtosecond laser (267 nm) as the ionization source. Numerous parent polycyclic aromatic hydrocarbons (PPAHs) were observed in a sample extracted from PM2.5, and their concentrations were determined to be in the range from 30 to 190 pg/m(3) for heavy PPAHs. Standard samples of nitrated polycyclic aromatic hydrocarbons (NPAHs) were examined, and the limits of detection were determined to be in the picogram range. The concentration of NPAH adsorbed on PM2.5 in the air was less than 900-1300 pg/m(3).

DOI： 10.1007/s13361-015-1276-x

Repository Public URL： https://hdl.handle.net/2324/7168685

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

In order to suppress the fragmentation and improve the sensitivity for determination of nitrated polycyclic aromatic hydrocarbons (NPAHs), the mechanism of multiphoton ionization was studied for the following representative NPAHs, 9-nitroanthracene, 3-nitrofluoranthene, and 1-nitropyrene. The analytes were extracted from the PM2.5 on the sampling filter ultrasonically, and were measured using gas chromatography/multiphoton ionization/time-of-flight mass spectrometry with a femtosecond tunable laser in the range from 267 to 405 nm. As a result, a molecular ion was observed as the major ion and fragmentation was suppressed at wavelengths longer than 345 nm. Furthermore, the detection limit measured at 345 nm was measured to be the subpicogram level. The organic compounds were extracted from a 2.19 mg sample of particulate matter 2.5 (PM2.5), and the extract was subjected to multiphoton ionization mass spectrometry after gas chromatograph separation. The background signals were drastically suppressed at 345 nm, and the target NPAHs, including 9-nitroanthracene and 1-nitropyrene, were detected, and their concentrations were determined to be 5 and 3 pg/m(3), respectively. (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.talanta.2015.03.027

Repository Public URL： https://hdl.handle.net/2324/7165072

Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI  

A gas was utilized in producing the third harmonic emission as a nonlinear optical medium for autocorrelation and frequency-resolved optical gating measurements to evaluate the pulse width and chirp of a Ti:sapphire laser. Due to a wide frequency domain available for a gas, this approach has potential for use in measuring the pulse width in the optical (ultraviolet/visible) region beyond one octave and thus for measuring an optical pulse width less than 1 fs.

DOI： 10.3390/app5020136

Repository Public URL： https://hdl.handle.net/2324/7165084

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：CLEO  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

Multiphoton ionization processes were studied for three types of explosives using a line-tunable ultraviolet femtosecond laser. When peroxides such as triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) were ionized through a nonresonant two-photon process, a molecular ion was dominantly observed by reducing the excess energy remaining in the ion. However, an aromatic nitro compound such as 2,4,6-trinitrotoluene (TNT) produced large signals arising from molecular and fragment ions by resonant two-photon ionization. In addition, only fragment ions were produced from a nonaromatic nitro compound such as 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), even when a resonant two-photon ionization process was employed, suggesting that a further reduction in excess energy would be necessary if a molecular ion were to be observed.

DOI： 10.1021/ac504667t

Repository Public URL： https://hdl.handle.net/2324/7170845

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

Triacetone triperoxide (TATP), an explosive compound, was measured using gas chromatography combined with multiphoton ionization time-of-flight mass spectrometry (GC/MPI-TOFMS). By decreasing the pulse width of a femtosecond laser from 80 to 35 fs, a molecular ion was drastically enhanced and was measured as one of the major ions in the mass spectrum. The detection limits obtained using the molecular (M center dot+) and fragment (C2H3O+) ions were similar or slightly superior to those obtained using conventional mass spectrometry based on electron and chemical ionization. In order to improve the reliability, an isotope of TATP, i.e., TATP-d18, was synthesized and used as an internal standard in the trace analysis of TATP in a sample of human blood. TATP could be identified in a two-dimensional display, even though numerous interfering compounds were present in the sample. Acetone, which is frequently used as a solvent in sampling TATP, produced a chemical species with a retention time nearly identical to that of TATP and provided a C2H3O+ fragment ion that was employed for measuring a chromatogram of TATP in conventional MS. This compound, the structure of which was assigned as phorone, was clearly differentiated from TATP based on a molecular ion observable in MPI-TOFMS. (C) 2014 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.aca.2014.10.045

Repository Public URL： https://hdl.handle.net/2324/7170842

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society for Analyitcal Chemistry  

Excitation energies, oscillator strengths, and vacuum-ultraviolet/deep-ultraviolet absorption spectra were calculated for nerve agents, such as sarin, soman, VX, tabun, mustard gas, and analogs. We used time-dependent density functional theory (TD-DFT) methods that included B3LYP combined with basis sets of cc-pVDZ and cc-pVTZ, and omega B97XD with cc-pVTZ. The vertical ionization energies were also calculated for these compounds, in order to collect additional information relative to the optimal pathways for multiphoton ionization in mass spectrometry.

DOI： 10.2116/analsci.30.1113

Repository Public URL： https://hdl.handle.net/2324/7170841

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

An autocorrelator consisting of a time-of-flight mass spectrometer as a two-photon-response detector was constructed for use in measuring an optical pulse width based on non-resonant two-photon ionization. An organic compound that can be two-photon ionized in a wide spectral region has the potential for use in measuring an optical pulse width approaching 1 fs. (C) 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.optcom.2013.07.055

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI  

The temporal profile of the second and third harmonic emissions of a Ti:sapphire laser was measured using an autocorrelator consisting of a mass spectrometer as a two-photon-response detector. A number of organic compounds that are potentially applicable for two-photon excitation and subsequent one-photon ionization were investigated using density functional theory calculations. N,N'-dimethylaniline and acetonitrile were used for the measurement of the pulse width for the second and third harmonic emissions of the Ti:sapphire laser. This approach has the potential for use in measuring pulse widths as short as 1-3 fs in the ultraviolet region.

DOI： 10.1007/s00340-013-5505-3

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

The frequency domain of non-resonant two-photon ionization, defined as a frequency separation from half of the ionization energy to the excitation energy, was investigated using density functional theory calculations. Several organic compounds have the potential for use in the measurement of the ultrashort optical pulse width in the ultraviolet region using an autocorrelator consisting of a mass spectrometer as a two-photon-response detector. (C) 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.optcom.2012.04.015

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry  

Gas chromatography combined with multiphoton ionization/time-of-flight mass spectrometry (GC/MPI/TOF-MS) using ultraviolet picosecond and femtosecond lasers was employed to quantitatively analyze a series of polybrominated diphenyl ethers (PBDEs). Congeners from monoBDE to tetraBDEs were analyzed using a picosecond laser emitting at 266 nm. In order to enhance the efficiency of ionization for highly brominated DEs via triplet levels, a different laser emitting at 213 nm was used. It was, however, difficult to quantify such congeners, even at this wavelength. This unexpected result can be explained by the photodecomposition of PBDEs from the triplet levels. On the other hand, all congeners from monoBDE to decaBDE were detected when a femtosecond laser emitting at 267 nm was employed. Interestingly, the isomers having a smaller number of Br atoms at the meta-positions were more efficiently ionized, and provided lower values of detection limit.

DOI： 10.1039/c1ay05355h

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

Gas chromatography/multiphoton ionization/time-of-flight mass spectrometry (GC/MPI/TOFMS) was utilized for analysis of a standard mixture sample containing 49 pesticides and 4 real samples using the third-harmonic emission (267 nm) of a femtosecond Ti:sapphire laser (100 fs) as the ionization source. A sample of a standard mixture of n-alkane was also measured for calibration of the retention time indices of the pesticides. Two photons are required for the excitation of n-alkane due to an absorption band located in the far ultraviolet region (140 nm). The n-alkane molecule in the excited state was subsequently ionized either directly or by absorbing another photon because of a high ionization potential. Due to a large excess of energy, the molecular ion was decomposed and formed many fragment ions. Compared to n-alkanes, most of the pesticides were softly ionized by the femtosecond laser: one photon was used for excitation and another was used for the subsequent ionization. The pesticides with no conjugated double bond had a lower ionization efficiency. The present analytical instrument was applied to several samples prepared from a variety of vegetables and a single fruit after pretreatment with solid-phase extraction. Three pesticides were found in these samples, although some of them were not detected by conventional GC/EI/MS-MS due to insufficient sensitivity and selectivity. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.aca.2011.06.003

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

Gas chromatography/multiphoton ionization/time-of-flight mass spectrometry (GC/MPI/TOF-MS) was developed for trace analysis of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). The use of an ultraviolet femtosecond laser (266 nm) allowed the sensitive, as well as selective, determination of PCDD/Fs with short singlet-excited-state lifetimes; the detection limit was 19 fg for 1,3,6,8-tetraCDF. Performance of the analytical instrument was examined and was ascertained to be satisfactory for all the criteria (K0311) prescribed by the Japanese Industrial Standards (JIS). The relative ionization efficiencies of C-12-native PCDD/Fs against C-13-labeled PCDD/Fs were 1.002 +/- 0.012. This suggests that C-13-labeled isotopes can be used as internal standards with no intensity calibration and that the concentrations of PCDD/Fs can be determined to within an error of ca. 1%. In addition, multiphoton ionization provides negligible levels of background interference for the real soil samples even with curtailed pretreatment. The toxicity equivalence (TEQ) of the real sample was determined using GC/MPI/TOF-MS for performance evaluation against high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). The results suggest equivalent or even superior performance for GC/MPI/TOF-MS, due to low background interference and to the ability to check the reliability of the assignment from the intensity distribution of the isotope peaks.

DOI： 10.1021/ac1009063

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

The spectral domain of an ultraviolet femtosecond laser was expanded by stimulated Raman scattering/four-wave Raman mixing, and the resulting laser pulse was compressed using a pair of gratings. The pulse width was then measured using an autocorrelator comprised of a Michelson interferometer equipped with a multiphoton ionization/mass spectrometer which was used as a two-photon detector. A gas chromatograph/mass spectrometer was employed to analyze triacetone triperoxide (TATP), and the molecular ion induced by multiphoton ionization was substantially enhanced by decreasing the laser pulse width.

DOI： 10.1021/ac1003773

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

This paper reexamines the structures and energies of dibenzofuran and twenty PCDFs in S-1-S-3 states. It was demonstrated that, although the CIS method gives a false relative ordering of excited states, the false ordering can be remedied by the CIS(D) method. Moreover the CIS geometries of typical PCDF molecules reasonably agree with their SAC-CI geometries. It was found that molecules chlorinated at the 1- and 9-positions are twisted in the S-2 state but are planar in other states, except for 1,4,6,9-TeCDF and fully chlorinated dibenzofuran (OCDF). The twisted structure of 1,4,6,9-TeCDF occurs in the S-3 state, but the structure of OCDF is twisted in every state. We partitioned the molecule into the parent structure and four chlorine groups and measured the twist energy with reference to the ground state. Then, the S-1 <- S-0 0-0 transition energies (i = 1, 2) calculated using the CIS(D) and MP2 methods could be expressed as a multiple linear equation with components and twist energy. It was further confirmed that if the multiple linear equation is corrected for residual correlation energies of the parent structure, it can predict the S-1 <- S-0 0-0 transition energies with high precision. (C) 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.theochem.2009.08.021

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Triacetone triperoxide (TATP), which is used as an explosive in acts of terrorism, was measured by means of gas chromatography/multiphoton ionization/time-of-flight mass spectrometry using a deep-ultraviolet (deep-UV) femtosecond laser as an ionization source. The fragmentation process was investigated by changing the intensity of the laser at the center axis of a molecular beam. A molecular ion was observed using a femtosecond laser, and the ratio of the intensities of the molecular and fragment ions decreased as the intensity of the laser increased. These results suggest that TATP can be efficiently ionized using a deep-UV, ultrashort optical pulse. Furthermore, fragmentation was accelerated by excess energy supplied through higher-order multiphoton processes under a strong radiation field. The detection limits obtained using the molecular ion and two dominant fragment ions, C(2)H(3)O(+) + and CH(3)(+) were determined to be 670, 83 and 150 pg, respectively. Copyright (C) 2009 John Wiley & Sons, Ltd.

DOI： 10.1002/rcm.4225

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society for Analytical Chemistry  

A Supersonic jet/resonance-enhanced multiphoton ionization/time-of-flight mass spectrum (SSJ/REMPI/TOF-MS) was measured for xylenols and ethylphenols. Sharp and intense peaks were observed in the REMPI spectrum of 2,4-xylenol. and the wavelength of the peak tentatively assigned to the 0-0 transition was the longest among xylenols and ethylphenols. These results suggest that 2,4-xylenol, designated as a Class 11 chemical Substance in the Pollutant Release and Transfer Register (PRTR), can be measured sensitively and selectively even when numerous isomers are Present in the sample.

DOI： 10.2116/analsci.25.599

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry  

DOI： 10.1039/b815630a

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

Gas chromatography/multiphoton ionization/time-of-flight mass spectrometry (GC/MPI/TOF-MS) was applied to the trace analysis of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). To determine the optimum wavelength for analysis of PCDD/Fs, the wavelength of the femtosecond laser utilized for multiphoton ionization was converted to near-ultraviolet status using stimulated Raman scattering. A femtosecond laser emitting at 300nm completely eliminated the background signal arising from the bleeding compounds generated from a stationary phase of the capillary column in GC. (C) 2008 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.aca.2008.11.005

Language：English   Publisher：the annual Dioxin Symposia  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

The geometries and energies for the So and S, states of dibenzoftiran (DF) and all 135 PCDFs were obtained using Hartree-Fock (HF) and CI-Singles (CIS) methods. The transition energies determined from HF and CIS energies were corrected for electron correlation. If the electron correlation energies for the So and the S, state are calculated using a second-order Moller-Plesset perturbation (MP2) and a perturbative correction to CIS (termed CIS(D)) method, the S-1 <- S-0 0-0 transition energies are given with an error of 15.4-22.6&#37;. Electron correlation corrections to the transition energies were determined from a selected set of experimental transition energies on the assumption of the following additivity rule: the electron correlation energy of each state can be partitioned into contributions from the parent molecule and substituent chlormes. The transition energies after correction for electron correlation are in good agreement with available experimental data with an error of 0.2-3.5&#37;. The validity of the additivity rule with respect to electron correlation energy is discussed in relation to the geometry of the molecule. The findings show that the additivity rule holds within an error of 0.4&#37;. Vertical ionization potentials, which are useful in REMPI spectral studies, were calculated using Koopmans' theorem. The results confirmed that the S-1 <- S-0 origin transition energy is inversely proportional to the number of chlorine atoms tic, but the ionization potential is directly proportional to n(Cl). (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.theoshem.2006.07.005

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

Geometries and S-1 <- S-0 origin transition energies for biphenyl, deuterated biphenyl, and 24 PCBs were obtained using a Hartree-Fock (HF), a single-excitation configuration interaction (CIS), and a related C1 method with doubles correction (CIS(D)). The HF and CIS geometries for biphenyl are in fairly good agreement with those obtained by a complete active space self-consistent field (CASSCF) method. Calculated results show that, in both S-0 and S-1 states of PCBs, the torsional angles and the inter-ring bond lengths can be classified according to the number of ortho-chlorine atoms, n(o-Cl). This suggests that the difference in electronic energy between the S-0 and the S-1 state also can be specified by n(o-cl). The HF and CIS energies were corrected for electron correlation on the assumption that the electron correlation energy can be partitioned into constituent contributions. Calculated S-1 <- S-0 origin transition energies agree with experimental values within an error of 2&#37;. This level of accuracy is comparable to that of the S-1 <- S-0 origin transition energy for biphenyl calculated using the CASSCF method. The correction for electron correlation energy is largely due to contributions of the parent molecule and ortho-chlorine atoms. The present results will facilitate the analysis of electronic spectra of PCBs. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.theochem.2006.06.009

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

It was confirmed that both quadrupole moments and polarizabilities of polychlorinated dibenzofurans (PCDFs), which were calculated using Hartree-Fock theory and/or density functional theory, change systematically with the chlorination pattern governing molecular charge distribution. A mathematical model based on ligand-receptor binding and solute-solvent interaction is reported to explain the difference in toxicity between PCDFs. Multiple regression analysis demonstrated that the difference in the potency of aryl hydrocarbon hydroxylase (AHH) and 7-ethoxyresorufln O-deethylase (EROD) inductions is mostly determined by the polarizabilities of PCDFs. This suggests that the interaction of a PCDF with the aryl hydrocarbon receptor (AhR) and its interaction with surrounding molecules in the cytosol are dispersion interactions rather than electrostatic interactions. Quadrupole moment, electron affinity, and absolute hardness do not appear to be significantly correlated with the differences in AHH and EROD activities among PCDFs. The entropy change of dissolution is important in predicting the AHH and EROD activities with good accuracy. A mathematical model is also used to study the differences in AhR binding between PCDFs.

DOI： 10.1021/tx049874f

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

Additivity of electron correlation energy and the ab initio MO calculation of (0-0) S-1 <- S-0 transition energies: polychlorinated dibenzofurans
The energies of the S-0 and S-1 states of polychlorinated dibenzofurans (PCDFs) were calculated using the Hartree-Fock (HF) and configuration interaction-singles (CIS) methods. We can obtain the (0-0) transition energies of PCDFs with good accuracy if the energies calculated using the HF and CIS methods are adjusted to take the electron correlation energy into account. The correlation energy of the S-0 state was calculated using the Moller-Plesset correlation correction truncated at the second order (MP2), and that of the S-1 state was determined using experimental data. The correlation energies for both S-0 and S-1 states were expressed as the sum of the contributions arising from dibenzofuran (DF) and substituted chlorine atoms. The energy of the ground state calculated using the additivity approximation was in good agreement with the energy given directly by the MP2 method. The (0-0) S-1<--S-0 transition energies corrected for electron correlation energy agreed well with the available experimental data. The approach proposed in this paper may be useful for the estimation of the electronic transition energy for large aromatic molecules. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.theochem.2004.08.003

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

Ab initio MO study on the S-1 <- S-0 transitions of polychlorinated dibenzo-p-dioxins
The optimized geometries for the S-0 and S-1 states of dibenzo-p-dioxin and eight polychlorinated dibenzo-p-dioxins (PCDDs) were obtained by using HF, B3LYP, or CIS methods. Calculated results were in good agreement with available X-ray crystallographic structures. The effects of substituent chlorine atoms and electronic excitation on the molecular geometries are discussed. The correlation energy was estimated by a comparison of (0-0) transition energies, calculated using HF and CIS methods, With observed energies. It was confirmed that the correlation energy of PCDD was primarily caused by the-electrons belonging to the benzene and central rings, and that substituted chlorine atoms made a relatively small contribution to the correlation energy. The correction for the correlation energy demonstrated that it was possible to make (0-0) transition energies agree with experimental energies within an error of 2&#37;. Electronic spectra were also studied on the basis of INDO/S calculations. (C) 2003 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0166-1280(02)00648-6

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

Optimized geometries and total energies for the So and S, states of five monochlorophenols and phenol were calculated using a 10-electron, 8-orbital CASSCF/6-31G(d). We investigated the effects of a substituent chlorine atom and the S-1 <-- S-0 excitation on the geometries and charge distributions. It is common to all monochlorophenols that the substituent chlorine atom makes the C-O bond shorten and that an empirical rule with respect to the internal ring angle concerned with the substituent chlorine atom holds true. The S-1 <-- S-0 excitation enlarges the carbon ring and reduces the C-H, C-O, and C-CI bond lengths. The O-H bond length and the C-O-H bond angle are almost invariant upon excitation. A structural approach based on van der Waals radii has clarified that cis-o-chlorophenol has a hydrogen bond in the S-1 state and that the interaction between the chlorine and oxygen atoms in a trans-o-chlorophenol affects its geometries for the S-0 and S-1 states. As to the origin energies of the S-1 <-- S-0 transitions, the present method can compete in terms of accuracy with a 8-electron, 7-orbital CASSCF/6-31G(d,p). The increasing order of the calculated origin transition energies of monochlorophenols and phenol is in qualitative agreement with experimental results. Zero-point corrections are important in identifying the electronic spectra of monochlorophenols. The relative stabilities of rotational isomers, and dipole moments as well, have been also studied in relation to experimental results.

DOI： 10.1021/jp011533c

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Physical Society of Japan  

Mean-field theory of the orientational ordering of dipolar guest molecules in beta-hydroquinone clathrate of SO2 and D2S
A clathrate consists of both a 'host' system and a 'guest' system composed of the enclosed molecules. Treating the guest system as a diluted dipolar one, we have investigated the effects on orientational phase, transitions of the cavity occupancy x, a crystal field W due to host molecules, the difference between atom-atom potentials and the ignorance of those contributions by the host system which are not involved in W. It is shown that self-consistency makes the transition temperature T-c a nonlinear function of x. The occurrence of a successive phase transition is shown to depend oil the higher order terms of W and on the difference in the potential model. It is also clarified that the host system may affect the estimation of T-c. We have further investigated to what extent classical statistical mechanics is applicable at low, temperatures. Results are discussed in relation to the experiments.

DOI： 10.1143/JPSJ.70.2603

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Physical Society of Japan  

DOI： 10.1143/jpsj.66.1364

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Physical Society of Japan  

Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Physical Society of Japan  

Authorship：Last author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Physical Society of Japan  

DOI： 10.1143/jpsj.63.593

Event date： 2023.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：熊本   Country：Japan  

Event date： 2022.12

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：大阪大学 東京ブランチ会議室   Country：Japan  

レーザーをイオン化光源とした共鳴イオン化、非共鳴イオン化の過程や、爆発物、アレルギー物質、環境汚染物質などへの応用、超短パルス光の発生、および小型の質量分析計の開発などの講演を行った。

Event date： 2022.11

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：オンライン   Country：Taiwan, Province of China  

Event date： 2022.9 - 2022.10

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Con Dao   Country：Viet Nam  

取得した特許の技術を用いた高繰返しフェムト秒レーザーと時間相関イオン計数装置を用いた飛行時間型質量分析計の開発に関して講演を行った。

Other Link： https://iop.vast.ac.vn/~icpa/2022/index_e.html

Event date： 2022.9 - 2022.10

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Con Dao   Country：Viet Nam  

質量分析のイオン化光源として用いるため近赤外領域と真空紫外領域での超短パルス光の発生の研究について発表した。

Other Link： https://iop.vast.ac.vn/~icpa/2022/index_e.html

Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Okayama Univ   Country：Japan  

Event date： 2022.7

Language：Japanese  

Venue：静岡県御前崎市   Country：Japan  

Event date： 2022.5

Language：English   Presentation type：Oral presentation (general)  

Venue：茨城   Country：Japan  

Event date： 2021.10

Language：English   Presentation type：Oral presentation (general)  

Venue：Taipei   Country：Taiwan, Province of China  

Event date： 2021.10

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Taipei   Country：Taiwan, Province of China  

近赤外に置いて最短のパルスを発生させ質量分析計のイオン化光源として応用した

Event date： 2021.10

Language：English   Presentation type：Oral presentation (general)  

Venue：Taipei   Country：Taiwan, Province of China  

Event date： 2021.10

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Taipei   Country：Taiwan, Province of China  

Event date： 2021.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2021.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2021.9

Language：English   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2021.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2021.5

Language：English   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：United States  

近赤外領域で最短パルスの発生と質量分析計のイオン化源としても応用を行った。

Event date： 2021.3

Language：English   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：United States  

長い飛行時間と短い飛行時間のフライトチューブを備えた時間相関単一イオン計数質量分析計を開発し、アレルゲン物質の微量分析を行った。

Event date： 2021.1

Language：Japanese   Presentation type：Oral presentation (invited, special)  

Venue：オンライン   Country：Japan  

フェムト秒レーザーをイオン化光源とするガスクロマトグラフ質量分析法の開発やその応用として廃棄物処理場の土壌分析によるダイオキシン類の測定や、香料中のアレルギー物質、化学兵器剤代謝物質、爆発物などの解析を行った。

Event date： 2020.9

Language：English   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Laser ionization time-of-flight mass spectrometry of drug-related compounds

Event date： 2020.9

Language：English   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Derivatization of perfluorocarboxylic acids with 2-bromomethylnaphthalene for gas chromatography combined with flame ionization detection/laser ionization mass spectrometry.

Event date： 2020.1

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Fukuoka   Country：Japan  

Studies on Ionization Mechanism of 4-Methylcyclohexanol for Observing a Molecular Ion

Event date： 2020.1

Language：English   Presentation type：Oral presentation (keynote)  

Venue：Fukuoka   Country：Japan  

Generation of an Intense Few-femtosecond Optical Pulse in the Near-Infrared and Deep-Ultraviolet Regions

Event date： 2020.1

Language：English   Presentation type：Oral presentation (keynote)  

Venue：Fukuoka   Country：Japan  

Trace Analysis of Organic Substances by Laser Ionization Mass Spectrometry

Event date： 2019.12

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Fukuoka   Country：Japan  

Analysis of Perfluorocarboxylic Acids by Femtosecond Laser Ionization Mass Spectrometry

Event date： 2019.11

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Fukuoka   Country：Japan  

Ionization Efficiencies of Chlorinated Pesticides at Different Femtosecond Laser Pulse Widths

Event date： 2019.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Fukuoka   Country：Japan  

Femtosecond Ionization Mass Spectrometry for Detection of Novichok: Quantum Chemical Calculation for the Spectral Properties

Event date： 2019.7

Language：English   Presentation type：Oral presentation (keynote)  

Venue：Taichung   Country：Taiwan, Province of China  

Laser Ionization Mass Spectrometry -Basic Principles and Applications-

Event date： 2019.7

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Taichung   Country：Taiwan, Province of China  

Spectroscopic Properties of “Novichok” Theoretically Calculated for Gas Chromatography/Femtosecond Ionization Mass Spectrometry

Event date： 2019.5

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Taipei   Country：Taiwan, Province of China  

Femtosecond Ionization Mass Spectrometry for Application to Forensic Science

Event date： 2019.5

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Taipei   Country：Taiwan, Province of China  

Study on Photoionization Process in Mass Spectrometry Based on Quantum Chemical Calculation

Event date： 2019.5

Language：English   Presentation type：Oral presentation (general)  

Venue：Kitakyushu   Country：Japan  

Gas chromatography/mass spectrometry of highly-toxic organochlorine pesticides using an ultraviolet femtosecond laser as an ionization source

Event date： 2019.1

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Snowbird   Country：United States  

Generation of a Vacuum-Ultraviolet Femtosecond Pulse via Four-Wave Raman Mixing and its Application to Mass Spectrometry

Event date： 2019.1

Language：English   Presentation type：Poster presentation  

Venue：Snowbird   Country：United States  

An Ultrashort Ultraviolet Optical Pulse for Ionization of Pesticides in Multiphoton Ionization Mass Spectrometry

Event date： 2019.1

Language：English   Presentation type：Poster presentation  

Venue：The Cliff Lodge, Snowbird, Utah, USA   Country：United States  

Event date： 2018.10

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Fukuoka   Country：Japan  

Analysis of Organochlorine Pesticides Using MultiphotonIonization Time-of-Flight Mass Spectrometry

Other Link： https://researchmap.jp/90-92

Event date： 2018.10

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Fukuoka   Country：Japan  

Design and Construction of Small-Frame Time-of-Flight MassSpectrometer

Other Link： https://researchmap.jp/90-92

Event date： 2018.10

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Fukuoka   Country：Japan  

Analysis of Perfluorocarboxylic Acids by GasChromatography/Multiphoton Ionization/Mass SpectrometryUsing a Femtosecond Laser

Other Link： https://researchmap.jp/90-92

Event date： 2018.10

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Fukuoka   Country：Japan  

Determination of Nerve Agent Metabolitesin Human Urine by Ultraviolet Femtosecond Laser IonizationMass Spectrometry Using Derivatization Reaction

Other Link： https://researchmap.jp/90-92

Event date： 2018.4

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Jakarta   Country：Indonesia  

Femtosecond ionization mass spectrometry for trace analysis of environmental pollutants adsorbed on particulate matter 2.5

Event date： 2018.4

Language：English   Presentation type：Oral presentation (general)  

Venue：Jakarta   Country：Indonesia  

Multi-residue determination of pesticides by femtosecond lasers ionization mass spectrometry

Event date： 2018.4

Language：English   Presentation type：Oral presentation (general)  

Venue：Jakarta   Country：Indonesia  

Event date： 2018.4

Language：English   Presentation type：Oral presentation (general)  

Venue：Jakarta   Country：Indonesia  

Photoionization mass spectrometry based on time-correlated single ion counting using a femtosecond laser

Event date： 2017.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Tokyo   Country：Japan  

Femtosecond laser induced ionization and dissociation of pentachlorobenzene studied by time-of-flight mass spectrometry

Event date： 2017.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Tokyo   Country：Japan  

Time-correlated single ion counting in time-of-flight femtosecond-laser-ionization mass spectrometry

Event date： 2017.8 - 2017.9

Language：English   Presentation type：Poster presentation  

Venue：Stockholm   Country：Sweden  

Theoretical calculation of the elution order of (+/-)-α-hexachlorocyclohexane separated by a stationary phase consisting of permethylated γ-cyclodextrin in gas chromatography

Event date： 2017.8 - 2017.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Stockholm   Country：Sweden  

Femtosecond ionization mass spectrometry -A new tool for practical trace analysis in environmental science and technology-

Event date： 2016.12

Language：English   Presentation type：Oral presentation (keynote)  

Venue：Brisbane   Country：Australia  

An ultraviolet femtosecond laser for multiphoton ionization in mass spectrometry

Event date： 2016.12

Language：English   Presentation type：Poster presentation  

Venue：Brisbane   Country：Australia  

Efficient nonresonant multiphoton ionization in the femtosecond region

Event date： 2016.12

Language：English   Presentation type：Oral presentation (keynote)  

Venue：Chiang Mai   Country：Thailand  

Femtosecond ionization mass spectrometry: an advanced tool for the analysis of pollutants, explosives, and nerve agents

Event date： 2016.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：Sapporo   Country：Japan  

Event date： 2016.5 - 2016.6

Language：English   Presentation type：Poster presentation  

Venue：the Congress Centre, Riva del Garda, Italy   Country：Italy  

Event date： 2016.5 - 2016.6

Language：English   Presentation type：Oral presentation (general)  

Venue：the Congress Centre, Riva del Garda, Italy   Country：Italy  

Event date： 2016.4 - 2016.7

Language：English   Presentation type：Oral presentation (general)  

Venue：University of Rostock, Rostock, Germany   Country：Germany  

Event date： 2016.1

Language：English   Presentation type：Oral presentation (invited, special)  

Country：United States  

Generation of Ultrashort Optical Pulses by Four-Wave Mixing in a Gaseous Medium

Event date： 2015.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Honolulu   Country：United States  

Time-of-flight mass spectrometry of polycyclic aromatic hydrocarbons and their analogs

Event date： 2015.9

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2015.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡（九州大学）   Country：Japan  

近年、大気汚染物質としてPM2.5が注視される。これに含まれる無置換多環芳香族炭化水素 (PPAHs)、ニトロ多環芳香族炭化水素(NPAHs) の一部は発がん性を持つことが知られている。本研究ではガスクロマトグラフィー/多光子イオン化/飛行時間型質量分析法(GC/MPI/ToF-MS)を用いたPM2.5中PAHsとNPAHsの分析について検討した。

Event date： 2015.5

Language：English   Presentation type：Oral presentation (general)  

Venue：甲府（山梨大学）   Country：Japan  

Event date： 2015.5

Language：English   Presentation type：Poster presentation  

Venue：San Jose   Country：United States  

A simple method for the measurement of the optical pulse width on-site the mass spectrometer

Event date： 2015.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東海大学 湘南キャンパス   Country：Japan  

Event date： 2014.9

Language：English  

Venue：Salzburg   Country：Austria  

Spectral properties evaluated using quantum chemical calculation for the measurement of the explosives

Event date： 2014.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：郡山市   Country：Japan  

Event date： 2013.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：近畿大学（東大阪キャンパス）   Country：Japan  

レーザーイオン化質量分析法は、特定の物質を選択的に測定する場合に極めて有効である。最近、テロなどで種々の爆発物が利用されているが、それらを効率よくイオン化する波長は求められていない。そこで、本研究では量子化学計算により、励起及びイオン化エネルギーを求め、これらを分析するための条件を明らかにした。

Event date： 2013.8

Language：English   Presentation type：Oral presentation (general)  

Venue：Fukuoka   Country：Japan  

Mass Spectrometer for Measuring an Autocorrelation Trace of an Ultrashort Optical Pulse in the Ultraviolet Region Based on Two-Photon Ionization of an Organic Compound

Event date： 2013.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Taipei   Country：Taiwan, Province of China  

Event date： 2012.9

Language：Others   Presentation type：Oral presentation (general)  

Venue：金沢   Country：Japan  

Event date： 2012.9

Language：Others   Presentation type：Oral presentation (general)  

Venue：松山   Country：Japan  

Event date： 2012.5

Language：English   Presentation type：Poster presentation  

Venue：San Jose   Country：United States  

Molecules with a One Octave Frequency Domain for the Measurement of the 1-fs Optical Pulse Width

Event date： 2011.9

Language：Others   Presentation type：Oral presentation (general)  

Venue：名古屋大学 東山キャンパス   Country：Japan  

Event date： 2011.5

Language：English   Presentation type：Oral presentation (general)  

Venue：Kyoto   Country：Japan  

Development of a Laser with an Ultimately-Short Optical Pulse Width for Impulsive Ionization to Obtain a Molecular Ion in Mass Spectrometry

Event date： 2011.3

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Other  

ガスクロマトグラフ/レーザー多光子イオン化/飛行時間型質量分析計を用いる農薬分析のための量子化学計算

Event date： 2010.9

Language：Others   Presentation type：Oral presentation (general)  

Venue：東北大学 川内北キャンパス   Country：Japan  

Event date： 2010.3

Language：Japanese  

Country：Other  

レーザーイオン化法による多臭素化ジフェニルエーテルのガスクロマトグラフィー‐質量分析

Event date： 2009.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Kyushu Univ   Country：Japan  

Event date： 2009.9

Language：Others   Presentation type：Oral presentation (general)  

Venue：北海道大学   Country：Japan  

Event date： 2009.8

Language：English   Presentation type：Oral presentation (general)  

Venue：Kuala Lumpur   Country：Malaysia  

Trace Analysis of Triacetone Triperoxide (TATP) by Means of Gas Chromatography Combined with Femtosecond Laser Ionization/Time-of-Flight Mass Spectrometry

Event date： 2008.11

Language：Others   Presentation type：Oral presentation (general)  

Venue：福岡市（アクロス福岡）   Country：Japan  

Event date： 2008.9

Language：Others   Presentation type：Oral presentation (general)  

Venue：福岡大学   Country：Japan  

Event date： 2008.8

Language：English   Presentation type：Oral presentation (general)  

Country：Other  

Gas Chromatography/Multiphoton Ionization/Mass Spectrometry of Pentachloro Dibenzofurans in Soil

Event date： 2008.3

Language：Others   Presentation type：Oral presentation (general)  

Venue：立教大学   Country：Japan  

Event date： 2007.8

Language：English   Presentation type：Oral presentation (general)  

Country：Other  

Multiphoton Ionization/Mass Spectrometry for Trace Analysis of Dioxin

Event date： 2005.10

Language：English   Presentation type：Oral presentation (general)  

Country：Other  

Electron Correlation Correction Method to Precisely Compute the (0-0) S1←S0 Transition Energies: Polychlorinated Biphenyls (PCBs)

Event date： 2004.3

Language：Others   Presentation type：Oral presentation (general)  

Venue：関西学院大学   Country：Japan  

Event date： 2003.3

Language：Others   Presentation type：Oral presentation (general)  

Venue：早稲田大学   Country：Japan  

Event date： 2001.3

Language：Others   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2000.3

Language：Others   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 1999.3

Language：Others   Presentation type：Oral presentation (general)  

Venue：神奈川大学   Country：Japan  

Event date： 1995.7

Language：Others   Presentation type：Oral presentation (general)  

Venue：九州大学   Country：Japan  

Event date： 1993.7

Language：Others   Presentation type：Oral presentation (general)  

Venue：Toyohashi   Country：Japan  

Event date： 2020.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2015.12

Language：English   Presentation type：Oral presentation (general)  

Country：Other  

Determination of nerve agent metabolites by gas chromatography/multiphoton ionization/time-of-flight mass spectrometry

Event date： 2015.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：甲府（山梨大学）   Country：Japan  

Event date： 2014.11

Language：English   Presentation type：Oral presentation (general)  

Country：Other  

Theoretical Prediction and Contribution to the experiment of the quantum chemistry calculation

Event date： 2014.9

Language：English   Presentation type：Oral presentation (general)  

Country：Other  

Trace analysis of triacetone triperoxide using gas chromatography combined with femtosecond laser ionization mass spectrometry

Event date： 2014.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：郡山市   Country：Japan  

Event date： 2014.1

Language：English   Presentation type：Oral presentation (general)  

Country：Other  

Generation of Numerous Raman Sidebands for Fourier Synthesis of an Ultrashort Optical Pulse beyond the 1-fs Barrier

Event date： 2012.9

Language：Others   Presentation type：Oral presentation (general)  

Venue：松山   Country：Japan  

Event date： 2011.5

Language：English  

Country：Other  

Determination of Polybrominated Diphenyl Ethers by Laser Ionization Mass Spectrometry

Event date： 2009.11 - 2008.11

Presentation type：Oral presentation (general)  

Venue：福岡市（アクロス福岡）   Country：Japan  

Event date： 2009.8

Language：English   Presentation type：Oral presentation (general)  

Country：Other  

Determination of 2,4-Xylenol by Gas Chromatography/Resonance-Enhanced Multiphoton Ionization/Time-of-Flight Mass Spectrometry Combined with Supersonic Jet Spectrometry

Event date： 2008.11

Language：English  

Country：Other  

Gas Chromatography/Multiphoton Ionization/Time-of-Flight Mass Spectrometry of Dioxins Using Femtosecond Laser

Event date： 2008.8

Language：Others   Presentation type：Oral presentation (general)  

Venue：Shanghai   Country：China  

Event date： 2008.7

Presentation type：Oral presentation (general)  

Venue：熊本市   Country：Japan  

The reliability evaluation and measurement of sample of soil of laser ionizaition mass spectrometry in dioxin analysis,　Nami Nakamura, Yuka Watanabe-Ezoe, Tomohiro Uchimura, Tomoko Imasaka and Totaro Imasaka, The Japan Society for Analytical Chemistry

Event date： 2006.10

Language：Others   Presentation type：Oral presentation (general)  

Venue：九州大学   Country：Japan  

Event date： 2006.5 - 2006.6

Presentation type：Oral presentation (general)  

Venue：九州大学   Country：Japan  

Event date： 2003.3

Language：Others   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2001.3

Language：Others   Presentation type：Oral presentation (general)  

Venue：甲南大学   Country：Japan  

Event date： 1996.3 - 2009.4

Language：Others   Presentation type：Oral presentation (general)  

Venue：金沢大学   Country：Japan  

Event date： 1993.3

Presentation type：Oral presentation (general)  

Venue：東北大学   Country：Japan  

The phase transition of three dimensional rotator, Shoji Hirokawa and Tomoko Imasaka, The Physical Society of Japan

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Other  

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Other  

Language：Others   Presentation type：Oral presentation (general)  

Country：Other  

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Other  

多塩素化ジベンゾフランのS₁←S₀電子遷移エネルギーのab initio MO計算と電子相関エネルギーの加算性

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Language：Japanese  

Country：Other  

5-222 The Aim of the Design Curriculum, "Can you forestall Picasso?"

Language：Japanese  

Language：Japanese  

Language：Japanese  

学外からの研究用システムの利用 量子化学計算

DOI： 10.15017/1470462

Language：Japanese   Publishing type：Internal/External technical report, pre-print, etc.  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Gaussianによる非経験的分子軌道法計算

DOI： 10.15017/1470414

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Type：Academic society, research group, etc. 

Number of participants：300

Type：Peer review 

Number of peer-reviewed articles in foreign language journals：1

I reviewed a paper submitted to the journal Analytical Chemistry published by the American Chemical Society.

Type：Academic society, research group, etc. 

Number of participants：1,300

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Type：Competition, symposium, etc. 

Number of participants：17

Type：Competition, symposium, etc. 

Number of participants：80

国際シンポジウム"Frontiers in Chemistry, Biology, and Earth Science -International Symposium between National Taiwan University and Kyushu University"を主宰し、台湾大学の林金全先生、何佳安先生、林志民先生をPleanary Lectureとして招へいした

国際シンポジウム"Challenge in Chemistry-The State-of-the-Art-International Symposium between National University of Singapore and Kyushu University"を主宰し、シンガポール大学のH. K. Lee先生をPleanary Lectureとして招へいした

「九州大学と国立台湾師範大学との国際連携のための教育と研究シンポジウム：Symposium on Education and Research for International Collaboration between Kyushu University and National Taiwan Normal University：平成30年10月22日」を主宰し、九州大学と台湾師範大学間の「大学間学術・学生交流協定」の締結に貢献した。

福岡県高等学校化学部会より、功労者として表彰され、感謝状を授与

英語による授業の実施としては大学院講義科目の環境化学特論 （2018.10-現在）が該当します。

英語による研究指導。指導した博士後期課程のWen Luさんを3年間（2019.10-2022.9）英語により指導しました。

博士学位取得者の輩出。指導した博士後期課程3年のWen Luさん（主指導教員：大井先生、副指導教員：今坂）が博士学位を取得して卒業しました。

指導学生の学術誌論文。指導したS. L. Madunilさんを第一著者（責任著者：今坂）とした論文をアメリカ化学会のAnalytical Chemistry誌に掲載しました。Analytical ChemistryはTop10％ジャーナルで、我々の研究成果は表紙にも掲載されました。
S. L. Madunil, T. Imasaka, and T. Imasaka, Determination of Barbiturates by Femtosecond Ionization Mass Spectrometry, Analytical Chemistry, vol. 94, pp. 14691-14698 (2022)

指導学生の受賞。指導したWen Luさんが日本分析化学会の九州分析化学奨励賞を受賞しました。研究タイトルは「環境汚染物質の分析のためのレーザーイオン化質量分析」。
この賞は、分析化学に関する優れた論文を発表した若手研究者に授与され、応募者の中から毎年２名程が選出されます。

学部1年生のクラス担任として指導を行った。

英語による研究指導。指導した博士後期課程のS. L. Madunilさんを3年間（2018.4-2021.3）英語により指導しました。

2019.11, 科学研究費や学内資金のアウトリーチ活動として、福岡県高等学校化学部会、九州大学未来化学創造センター等と連携し、2011年度まで行っていた九州大学の社会連携活動（事業名：高校の化学クラブ活動への支援および調査・研究）の事業を継続して推進した。福岡工業大学附属城東高校科学部の化学および生物クラブ生を伊都キャンパスの研究室に招き、研究・プレゼンテーションなどの指導を行った。

国立台湾師範大学の修士課程学生のChen Kuan-Hao氏とWu Luo-Xian氏を受入れ（経費は国立台湾師範大学）、共同研究を行った。その成果を”The application of multiphoton ionization mass spectrometry in human breath analysis”のタイトルで発表した。

2018.11,科学研究費のアウトリーチ活動として、福岡県高等学校化学部会、九州大学未来化学創造センター等と連携し、2011年度まで行っていた九州大学の社会連携活動（事業名：高校の化学クラブ活動への支援および調査・研究）の事業を継続して推進した。福岡県立修猷館高等学校や福岡工業大学附属城東高校科学部の化学および生物クラブ生を伊都キャンパスの研究室に招き、研究・プレゼンテーションなどの指導を行った（福岡工業大学附属城東高校科学部より全国高文連の県大会で最優秀賞（生物）と優秀賞（化学）を獲得して、それぞれ全国大会、九州大会に進めることができた旨、報告を受けた）。

2017.11,科学研究費のアウトリーチ活動として、福岡県高等学校化学部会、九州大学工学研究院応用化学部門（機能）等と連携し、2011年度まで行っていた九州大学の社会連携活動（事業名：高校の化学クラブ活動への支援および調査・研究）の事業を継続して推進した。

2016.11,科学研究費のアウトリーチ活動として、福岡県高等学校化学部会、九州大学工学研究院応用化学部門（機能）等と連携し、2011年度まで行っていた九州大学の社会連携活動（事業名：高校の化学クラブ活動への支援および調査・研究）の事業を継続して推進した。

2014.11,科学研究費のアウトリーチ活動として、福岡県高等学校化学部会、九州大学工学研究院応用化学部門（機能）等と連携し、2011年度まで行っていた九州大学の社会連携活動（事業名：高校の化学クラブ活動への支援および調査・研究）の事業を継続して推進した。

2013.11,科学研究費のアウトリーチ活動として、福岡県高等学校化学部会、九州大学工学研究院応用化学部門（機能）等と連携し、2011年度まで行っていた九州大学の社会連携活動（事業名：高校の化学クラブ活動への支援および調査・研究）の事業を継続して推進した。

2012.11,科学研究費のアウトリーチ活動として、福岡県高等学校化学部会、九州大学工学研究院応用化学部門（機能）等と連携し、2011年度まで行っていた九州大学の社会連携活動（事業名：高校の化学クラブ活動への支援および調査・研究）の事業を継続して推進した。

九州大学の平成23年度戦略的研究教育推進経費（社会連携活動経費）（事業名：高校の化学クラブ活動への支援および調査・研究）（代表）の採択を受け、福岡県高等学校化学部会、九州大学工学研究院応用化学部門（機能）等と連携し、事業を推進した。

九州大学の平成22年度戦略的研究教育推進経費（社会連携活動経費）（事業名：高校の化学クラブ活動への支援および調査・研究）（代表）の採択を受け、福岡県高等学校化学部会、九州大学工学研究院応用化学部門（機能）等と連携し、事業を推進した。

九州大学の平成21年度戦略的研究教育推進経費（社会連携活動経費）（事業名：高校の化学クラブ活動への支援および調査・研究）（代表）の採択を受け、福岡県高等学校化学部会、九州大学工学研究院応用化学部門（機能）等と連携し、事業を推進した。

九州大学の平成20年度戦略的研究教育推進経費（社会連携活動経費）（事業名：高校の化学クラブ活動の支援および調査・研究）（代表）の採択を受け、福岡県高等学校化学部会、九州大学工学研究院応用化学部門(機能)九州大学未来化学創造センター等と連携し、事業を推進した。

日本学術振興会の平成１９年度　ひらめき☆ときめき サイエンス～ようこそ大学の研究室へ～ＫＡＫＥＮＨＩ（研究成果の社会還元・普及事業）（代表：今坂藤太郎）に参画し、高等学校の生徒の教育に寄与した。

九州大学の平成１８年度　戦略的研究教育推進経費（社会連携事業）（代表）の採択を受け、福岡県立修猷館高等学校、同立福岡高等学校、九州大学工学研究院応用化学部門（機能）、中央分析センター伊都分室、九州大学親和会等と連携し、事業を推進した。

2003～2007年度　基礎化学実験の実験指導およびレポート採点等の補助に従事
2008年度～　自然科学総合実験の実験指導等の補助に従事

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Audience：Infants,　Schoolchildren,　Junior students,　High school students

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Audience：Infants,　Schoolchildren,　Junior students,　High school students

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Audience：Infants,　Schoolchildren,　Junior students,　High school students

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Audience：Infants,　Schoolchildren,　Junior students,　High school students

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Audience：Infants,　Schoolchildren,　Junior students,　High school students

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Audience：Infants,　Schoolchildren,　Junior students,　High school students

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Type：Science cafe

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Audience：Infants,　Schoolchildren,　Junior students,　High school students

Type：Seminar, workshop

Type：Science cafe

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Type：Seminar, workshop

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