研究者詳細 - 神﨑　亮

論文 - 神﨑　亮

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Ryo Kanzaki, Tomoya Hidaka, Shinji Tajima, Hitoshi Kodamatani, Takashi Tomiyasu . The "pH-window" of a representative deep eutectic solvent and evaluation of electrodes for pH measurement . Chemical Physics Letters881 142475 2025年12月査読

神﨑亮 . 自己解離反応から見た現代の溶媒 . 分析化学74 ( 9 ) 469 - 478 2025年9月招待査読

担当区分：筆頭著者,　責任著者記述言語：日本語出版者・発行元：公益社団法人日本分析化学会

<p>酸塩基反応は分離や濃縮など分析化学的操作の起点である．水が酸塩基反応の媒体となり得るのは，水がH<sup>＋</sup>供与性と受容性を併せ持つためである．非水溶媒でも同じ性質を持つものがある．これらの溶媒中では自己解離反応が起こっており，この反応は酸塩基反応媒体として最も基本的である．本稿では，近年，酸塩基反応媒体として注目されている，プロトン性イオン液体（PIL），超濃厚電解質水溶液，及び深共融溶媒（DES）中における自己解離平衡や関係する酸塩基反応について得られた，著者のこれまでの成果を概説する．PILでは，構成イオンの水溶液中の酸塩基性が，PILの酸塩基挙動におおむね反映されていると結論付けられた．リチウムビス（トリフルオロメタンスルホニル）アミド超濃厚電解質水溶液では，Debye-Hückel理論からの予想に反して，水素イオン活量がエンタルピー的な要因によって増加し，結果として自己解離反応が抑制されることが示された．DESにおいては，自己解離平衡に成分間の相互作用が影響することが示唆された．これらの知見は，新しい溶媒の酸塩基特性の理解と溶媒設計への指針において，重要な示唆を与えるものである．</p>

DOI： 10.2116/bunsekikagaku.74.469

Kanzaki R., Guibert C., Fresnais J., Peyre V. . Ionization thermodynamics of poly(acrylic acid) in ionic liquids . Journal of Molecular Liquids437 128261 2025年8月査読国際共著

神﨑　亮 . 3級アンモニウム系イオン液体中におけるトリフルオロメタンスルホン酸とビス（トリフルオロメタンスルホニル）アミドのBrønsted酸塩基性 . 溶液化学研究会誌7 11 - 13 2025年4月招待

Kanzaki R., Hidaka T., Kodamatani H., Tomiyasu T., Fujii K. . Proton-transfer reaction thermodynamics in highly concentrated electrolytes for advanced aqueous lithium-ion batteries . Journal of Molecular Liquids427 127388 2025年3月査読

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Molecular Liquids

We have studied proton-transfer reactions in highly concentrated aqueous electrolytes focusing on lithium bis(trifluoromethanesulfonyl)amide (LiTf2N) for potential applications in advanced aqueous lithium-ion batteries. In 20 mol kg−1 LiTf2N aqueous solution, the autoprotolysis constant pKW increased significantly to 16.2, indicating a reduction in ionization compared to bulk water (pKW = 14 at infinite dilution), and the H+ concentration is lower than in dilute aqueous solutions. This was mainly attributed to the increase in the activity coefficient of H+ (γH) with increasing LiTf2N concentration. Calorimetric measurements revealed that the increase in pKW is driven by an increase in the autoprotolysis enthalpy, suggesting that H+ is enthalpically unfavorable in concentrated LiTf2N solutions. In contrast, the autoprotolysis entropy showed no significant contribution to the pKW variation. We extended this study to the acid-base reaction of acetic acid as a model system in highly concentrated electrolyte solutions. The pKa value of acetic acid (or the corresponding ionization Gibbs energy) showed little dependence on the LiTf2N concentration. In contrast, the corresponding ionization enthalpy and entropy increased significantly with increasing LiTf2N concentration. Due to the enthalpy–entropy compensation effect, the pKa value resulted in limited variation even under highly concentrated conditions. The obtained enthalpy values for the ionization processes support that proton carriers lie in an enthalpically unstable state. These findings provide new insights into the fundamental behavior of protons in highly concentrated aqueous electrolytes, which is critical for the design and optimization of aqueous lithium-ion batteries and other electrochemical systems.

DOI： 10.1016/j.molliq.2025.127388

Nishioka K., Okada M., Kanzaki R., Fukami K., Murase K. . Copper (II)-Lactate Complexes in Cu<inf>2</inf>O Electrodeposition Baths: Stability of the Complexes and Aging of the Baths . Journal of the Electrochemical Society172 ( 3 ) 2025年3月

記述言語：日本語出版者・発行元：Journal of the Electrochemical Society

The electrodeposition of Cu2O, represented by the reaction 2Cu(II) + 2OH− +2e → Cu2O + H2O in alkaline baths containing concentrated lactic acid (approximately 3 mol dm−3) as ligands, has been widely studied. In a previous study, such baths were found to generate the complexes [Cu(H−1L)L]− and [Cu(H−1L)2]2− (where L− = CH3CH(OH)COO− and H−1L− = CH3CH(O−)COO−) in a manner dependent on the bath pH in the alkaline region. This work first assessed the stability of these Cu(II)-lactate complexes based on computational chemistry. The formation of these complexes typically requires approximately one day to reach thermodynamic equilibrium, suggesting that other kinetically favorable, metastable complexes may form prior to the equilibrium complexes. Based on titration curves, [CuL2(HL)]0 was identified as the most likely such intermediate and the effect of this complex on deposition orientation was examined. Electrodeposited Cu2O obtained from a bath not yet at equilibrium with a pH of approximately 9.5 was randomly oriented whereas deposits from an equilibrated bath showed a preferential 〈100〉 orientation. These findings suggest that bath aging is an essential step in achieving reproducible Cu2O electrodeposition. Additionally, modifying the bath preparation method was found to prevent the formation of metastable complexes.

DOI： 10.1149/1945-7111/adc2a1

Kanzaki R., Hidaka T., Tokuda Y., Kodamatani H., Tomiyasu T. . Brønsted acidity of bis(trifluoromethanesulfonyl)amide and trifluoromethanesulfonic acid in ionic liquids of ternary ammonium . Journal of Molecular Liquids409 2024年9月

担当区分：筆頭著者,　責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Molecular Liquids

Bis(trifluoromethanesulfonyl)amide (Tf2N−) and triflate (TfO−) are commonly used anions of protic ionic liquids (PILs). They are the conjugate anions of strong acids, Tf2NH and TfOH, whose Brønsted acidities crucially influence the performance of the PILs. In this study, the Brønsted acidity of Tf2NH and TfOH was compared directly through potentiometric titrations carried out in the ionic liquids of ternary ammonium salts. As a result, Tf2NH exhibits stronger Brønsted acidity than TfOH by approximately 2 pH units. Furthermore, calorimetric titrations revealed that this difference originates from differences in their entropy states. This suggests that the solvation state, rather than the properties in their isolated state, has a more significant impact on the acidities of Tf2NH and TfOH. Besides, ionization thermodynamics turned out to be governed by both the constituent cations and anions of the PILs. Therefore, once the acid-base natures of the constituent ions are characterized, the overall acid-base behavior of the PIL may become predictable.

DOI： 10.1016/j.molliq.2024.125433

Tomiyasu T., Nozoe C., Ruiz W.L.G., Kodamatani H., Kanzaki R. . Distribution of selenium and mercury concentrations in sediments of Kagoshima Bay: can submarine volcanic activity affect the distribution of selenium in sediments? . Environmental Earth Sciences82 ( 20 ) 2023年10月査読

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Environmental Earth Sciences

Strong geothermal activity is observed at the bottom of Kagoshima Bay. The impact of volcanic activity on the sediment can be estimated by using the mercury concentration as an indicator. In this study, the distribution of selenium in the sediment of Kagoshima Bay was investigated and compared with the mercury concentration to estimate the impact of submarine volcanic activity on the selenium concentration in sediment. The selenium concentrations in sediment from 7 locations were in the range of 0.24–0.54 mg kg−1, which is approximately equal to the world shale average of 0.6 mg kg−1. A positive correlation was observed between total organic content and selenium, which suggested that the primary source of selenium in sediment is marine biological materials. On the other hand, in the geothermal area, the higher the mercury concentration is, the higher the Se concentration, which suggests that geothermal activity supplies selenium to the surrounding sediment.

DOI： 10.1007/s12665-023-11159-9

その他リンク： https://link.springer.com/article/10.1007/s12665-023-11159-9/fulltext.html

Tomiyasu T., Matsuki H., Oda M., Kodamatani H., Kanzaki R., Kobari T. . Impact of mercury discharged from submarine volcano on inner bay ecosystems . Chemosphere339 139748 2023年10月査読

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemosphere

Organic mercury, inorganic mercury and total mercury concentrations in phytoplankton (<0.1 mm) and zooplankton (>0.1 mm) collected in Kagoshima Bay, Japan were measured from 2017 to 2019 to estimate the impact of mercury discharged from submarine volcanoes on ecosystems; submarine volcanic activity continues at a depth of 200 m in the inner part of Kagoshima Bay. The total mercury concentrations in phyto- and zooplankton collected by vertical hauling at 0–200 m at just above the submarine volcano were in the range of 0.11–2.0 mg kg−1 (avg. 0.67 mg kg−1) and 0.090–0.56 mg kg−1 (avg. 0.21 mg kg−1), respectively. These values were one order of magnitude higher than the values in plankton collected in the central part of Kagoshima Bay. Organic mercury concentrations in phyto- and zooplankton were <0.010–0.071 mg kg−1 (avg. 0.028 mg kg−1) and 0.012–0.25 mg kg−1 (avg. 0.10 mg kg−1), respectively, for the inner part, and <0.010–0.040 mg kg−1 (avg. 0.010 mg kg−1) and <0.010–0.025 mg kg−1 (avg. 0.012 mg kg−1), respectively, for the central part. The values obtained in the inner part of the bay increased in summer and decreased in winter, which was consistent with changes in seawater mercury concentrations affected by volcanic activity. The organic mercury concentration in zooplankton collected just above the submarine volcano showed a size dependency, and a higher value was observed in the larger size, which suggested that the discharged mercury from the volcano was absorbed and concentrated through the ecosystem.

DOI： 10.1016/j.chemosphere.2023.139748

Kanzaki R., Hidaka T., Kodamatani H., Tomiyasu T. . Determination of autoprotolysis (autoionization) constant according to gran's procedure on potentiometric titrations . Journal of Molecular Liquids384 2023年8月査読

担当区分：筆頭著者,　責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Molecular Liquids

Gran's plot is an ingenious tool to find endpoints in potentiometric neutralization titrations. It can also be utilized for determining the formal potential of the electrodes, which is required in the case of obtaining the hydrogen ion concentration with pH sensor electrodes involving glass electrodes. Furthermore, autoprotolysis constants can be determined through Gran's plots with high accuracy, even those containing impurities. Gran's plot is thus a fundamental technique for investigating the properties of novel solvents such as protic ionic liquids as acid-base media. However, there are limitations in the autoprotolysis constants of the solvents and the ionization constants of the impurities, and so on, where Gran's plots work well. Hence, we have clarified the reliable range of these constants to be determined through Gran's plot by calculating the titration curves under various conditions and simulating these determination processes.

DOI： 10.1016/j.molliq.2023.122180

kanzaki R. . Deep eutectic solvents for liquid–liquid extraction . Analytical Sciences39 ( 7 ) 1021 - 1022 2023年6月招待

担当区分：筆頭著者,　責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Analytical Sciences

DOI： 10.1007/s44211-023-00362-0

その他リンク： https://link.springer.com/article/10.1007/s44211-023-00362-0/fulltext.html

Tomiyasu T., Shitauchi R., Kasai D., Kitagawa T., Kodamatani H., Kanzaki R. . The distribution and dynamics of residual mercury from the Chisso chemical plant in sediments of the Yatsushiro Sea, western Kyushu, Japan: have recent sedimentations lowered surface mercury concentrations? . Environmental Science and Pollution Research30 ( 28 ) 72769 - 72781 2023年6月査読国際誌

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Environmental Science and Pollution Research

To determine the long-term dynamics of mercury discharged from Chisso chemical plant between 1932 and 1968, the vertical variation in mercury concentrations in Yatsushiro Sea sediments was studied from 2013 to 2020 at 31 locations and compared to the mercury concentration distribution obtained in 1996. The results suggest that new sedimentation occurred after 1996, but the mercury concentrations at the surface ranged from 0.2 to 1.9 mg kg−1, which did not decrease significantly over a 20-year period. It was estimated that approximately 17 t of mercury remained in the southern Yatsushiro Sea sediment, which is equivalent to 10–20% of the total mercury discharged between 1932 and 1968. From results of WD-XRF and TOC measurement, it was suggested that mercury in sediment had been transported with suspended particles derived from sludges from the chemical plant and further suggests that the suspended particles derived from the sediment surface layer are still slowly diffusing.

DOI： 10.1007/s11356-023-27505-0

Kodamatani H., Kubo S., Takeuchi A., Kanzaki R., Tomiyasu T. . Sensitive Detection of Nitrite and Nitrate in Seawater by 222 nm UV-Irradiated Photochemical Conversion to Peroxynitrite and Ion Chromatography-Luminol Chemiluminescence System . Environmental Science and Technology57 ( 14 ) 5924 - 5933 2023年4月国際誌

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Environmental Science and Technology

Sensitive detection methods for nitrite (NO2-) and nitrate (NO3-) ions are essential to understand the nitrogen cycle and for environmental protection and public health. Herein, we report a detection method that combines ion-chromatographic separation of NO2- and NO3-, on-line photochemical conversion of these ions to peroxynitrite (ONOO-) by irradiation with a 222 nm excimer lamp, and chemiluminescence from the reaction between luminol and ONOO-. The detection limits for NO2- and NO3- were 0.01 and 0.03 μM, respectively, with linear ranges of 0.010-2.0 and 0.10-3.0 μM, respectively, at an injection volume of 1 μL. The results obtained by the proposed method for seawater analysis corresponded with those of a reference method (AutoAnalyzer based on the Griess reaction). As luminol chemiluminescence can measure ONOO- at picomolar concentrations, our method is expected to be able to detect NO2- and NO3- at picomolar concentrations owing to the high conversion ratio to ONOO- (>60%), assuming that contamination and background chemiluminescence issues can be resolved. This method has the potential to emerge as an innovative technology for NO2- and NO3- detection in various samples.

DOI： 10.1021/acs.est.3c00273

Tomiyasu T., Yasumatsu S., Kodamatani H., Kanzaki R., Takenaka C., Murao S., Miyagawa S., Nonaka K., Ikeguchi A., Navarrete I.A. . The dynamics of mercury around an artisanal and small-scale gold mining area, Camarines Norte, Philippines . Environmental Science and Pollution Research30 ( 8 ) 20052 - 20064 2023年2月査読国際誌

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Environmental Science and Pollution Research

To elucidate the dynamics of mercury emitted and released by artisanal and small-scale gold mining (ASGM) activity and to estimate its impact on the ecosystems of the bay, the distribution of mercury in the atmosphere, soil, water, and sediment around Mambulao Bay, Camarines Norte, Philippines, was investigated. The ASGM operations use mercury to extract gold from ore and are located on the east shore side of the bay. Samplings were conducted in August 2017 and September 2018. The samples were used for determination of total mercury (T-Hg) and organic mercury (org-Hg) concentrations, total organic carbon (TOC) content, and chemical composition. The atmospheric mercury concentration on the east shore side, 6.1–25.8 ng m−3, was significantly higher than the value of 1.4–9.9 ng m−3 observed on the west shore side. The average concentrations of T-Hg in the forest soils of the west shore side and those of the east shore side were 0.081 ± 0.028 mg kg−1 and 0.496 ± 0.439 mg kg–1, respectively. In the vertical distribution of T-Hg in the soil of the east shore side, a higher concentration was observed near the surface. For the vertical variations in T-Hg in the marine sediment, higher values were observed near the estuary, and the vertical variations in core samples showed an increase in mercury concentration toward the surface. The highest concentration of T-Hg in sediment, 9.5 mg kg−1, which was 2 orders of magnitude higher than the background levels of this area, was found near the river mouth. The T-Hg, org-Hg, and TOC levels showed a positive correlation, suggesting that the rivers are the main sources of T-Hg and org-Hg in the bay. Although the fish sample containing a mercury content higher than the regulatory level for fish and shellfish of 0.4 mg kg−1 in Japan was only one of 42 samples, the percentage of org-Hg in fish samples was 91 ± 18%. Mercury released into the surroundings by the ASGM activities can be converted into methylmercury and affect the bay’s ecosystem.

DOI： 10.1007/s11356-022-23497-5

Kodamatani H., Kubozono K., Kanzaki R., Tomiyasu T., Fujioka T. . Reverse osmosis membrane-based pretreatment for the quantification of N-nitrosodimethylamine concentrations in high-matrix water samples . Environmental Science: Water Research and Technology9 ( 10 ) 2553 - 2560 2023年査読

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Environmental Science: Water Research and Technology

N-Nitrosodimethylamine (NDMA) is a carcinogenic constituent commonly found in recycled water and pharmaceuticals. Developing an analytical method to continuously monitor changes in NDMA concentrations during water recycling and pharmaceutical manufacturing can mitigate accidents caused by NDMA formation. However, NDMA analysis in high-matrix water samples, such as beverages, wastewater, and pharmaceutical ingredients, is difficult. In this study, we adapted reverse osmosis (RO) membrane treatment as a pretreatment for NDMA analysis by isolating NDMA from interfering substances in high-matrix water samples. Subsequently, high-performance liquid chromatography-chemiluminescence detection was used for NDMA analysis. In a pure water matrix, 95% of NDMA can pass through at a low permeate flux of 1 L m−2 h−1. The method was then validated using beer, which is known to contain high concentrations of NDMA, as a representative high-matrix water sample. We found that RO pretreatment leads to clean chromatograms in which NDMA peaks are clearly visible while other peaks are mostly absent. Analysis of six different beer samples showed a maximum NDMA concentration of 315 ng L−1, and an average NDMA concentration of 138 ± 83 ng L−1 (n = 6), which fall within the regulation limits for NDMA in beer in the United States of America. The proposed pretreatment method has the potential to provide a platform for developing technologies for continuous monitoring of NDMA in aqueous solutions.

DOI： 10.1039/d3ew00222e

Tomiyasu T., Mitsui A., Mitarai M., Kodamatani H., Kanzaki R. . Seasonal variation in mercury species in seawater of Kagoshima Bay, southern Kyushu, Japan: The impact of active submarine volcanos on the inner bay . Marine Chemistry244 2022年7月査読

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Marine Chemistry

Wakamiko Proto-Caldera, a submarine volcano, is located at the bottom of the sea in the bay head area of Kagoshima Bay. In Kagoshima Bay, several species of fish with total mercury exceeding the provisional regulation value of 0.40 mg kg−1 were found in the 1970s. The effects of mercury released from submarine volcanoes are suspected. However, the path from volcanic mercury to the broader ecosystem has not yet been clarified. In this study, as the first step to elucidate the impact of volcanic activity on the ecosystems of Kagoshima Bay, seasonal changes in the concentrations of dissolved gaseous mercury (DGM), Hg(II), filtered total mercury (FT-Hg), particulate mercury (P-Hg), and mercury in suspended particulate matter (Hg in SPM) in seawater of Kagoshima Bay were tracked every two months from Feb. 2014 to Dec. 2017. The dissolved total mercury (DT-Hg) concentration was calculated by summing the DGM and FT-Hg concentrations. The DT-Hg at the location in the caldera ranged from 0.09 to 6.83 ng L−1 showing higher values in summer compared to winter, that is, in the stratified period. The P-Hg showed similar periodic variation as DT-Hg, and the highest Hg in SPM was 2.15 mg kg−1, which is one order of magnitude higher than that observed at the reference site. The high mercury concentration in SPM suggests the accumulation of dissolved mercury discharged from volcanic activity on SPM. Since mercury loaded on SPM can be taken up by suspension feeders and enter the food chain, the Hg in SPM may be a key factor affecting Hg in fishes in Kagoshima Bay.

DOI： 10.1016/j.marchem.2022.104133

Kodamatani H., Shigetomi A., Akama J., Kanzaki R., Tomiyasu T. . Distribution, alkylation, and migration of mercury in soil discharged from the Itomuka mercury mine . Science of the Total Environment815 152492 - 152492 2022年4月査読国際誌

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Science of the Total Environment

The purpose of this study was to investigate the behavior of previously discharged mercury (Hg) released from the Itomuka Hg mine into the surrounding environment, especially into soil. Total-Hg (T-Hg), methylmercury (MeHg), and ethylmercury (EtHg) concentrations in the surface soil at eight sample sites around the mine were 3.8–64.2 mg/kg, 6.0–54.7 μg/kg, and undetected to 4.5 μg/kg, respectively. Core samples collected from seven of the eight sample sites showed that the vertical distribution of T-Hg was the highest in the surface soil layer and decreased rapidly in the lower layers. A strong positive correlation was observed between T-Hg and MeHg concentrations in the core samples; however, the slope of the regression line varied considerably for each core. This suggests that Hg and MeHg were not supplied from the atmosphere simultaneously, but rather that MeHg was produced on-site. Further, the formation of MeHg and EtHg in soil was considered in terms of the total organic carbon/total nitrogen ratio, which is a decomposition index of soil organic matter. The strong positive correlation between T-Hg and MeHg can be attributed to the migration of organic matter containing Hg species to the lower layers. There was no relationship between T-Hg and MeHg at the riverbed sample site because of the high T-Hg in the lower soil layers, suggesting that Hg was supplied by ore at this sample site. These assumptions of the formation change and migration of Hg in soil were supported by the results of the fractionation experiment and the elution test. To understand the current conditions in this area, measurements of Hg in the water, sediment, atmosphere, and plants were also conducted.

DOI： 10.1016/j.scitotenv.2021.152492

Kanzaki R., Sako M., Kodamatani H., Tomiyasu T., Guibert C., Fresnais J., Peyre V. . Enthalpy profile of pH-induced flocculation and redispersion of polyacrylic acid-coated nanoparticles in protic ionic liquid, N,N-diethylethanolammonium trifluoromethanesulfonate . Journal of Molecular Liquids349 2022年3月査読国際共著

担当区分：筆頭著者,　責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Molecular Liquids

Maghemite nanoparticles coated with polyacrylic acid (pAA) were dispersed in the protic ionic liquid, diethylethanolammonium trifluoromethanesulfonate (DEEAH+⋅TfO−), and the thermodynamics of particle dispersion was studied by means of potentiometric and calorimetric titrations over the entire accessible pH range. As previously reported, the domain of colloidal stability is divided into two pH regions, mildly acidic and basic, separated by a flocculation domain at an intermediate pH. In this study, solvent DEEAH+⋅TfO− was first characterized in terms of the thermodynamic parameters of two reference reactions: autoprotolysis and ionization of acetic acid. A negative autoprotolysis entropy is obtained due to hydrogen-bond formation between the neutralized solvent cation, DEEA, and the neighboring cation DEEAH+. This suggests that the solvent structure is reinforced by the formation of neutral species, being an opposite trend to both ethylammonium nitrate and water. Second, the ionization and flocculation of pAA-coated nanoparticles (CNps) in the ionic liquid were examined. The potentiometric results could be modeled using a simple pAA ionization, independent of the aggregation state over the entire pH range. However, the calorimetric titration detected extra heat generation in an acidic condition prior to flocculation, in addition to an ionization enthalpy of pAA of 30 kJ/mol. This exothermic contribution is attributed to a change in the solvation process of CNps in the ionic liquid. Herein, we propose a model in which different types of solvation in the acidic and basic domains are sufficient to ensure colloidal stability, while aggregation unfolds between the switching pH.

DOI： 10.1016/j.molliq.2021.118146

Kodamatani H., Yoshimine D., Fujioka T., Kanzaki R., Tomiyasu T. . A novel luminol chemiluminescence induced by photoexcited ketones: A selective determination method for acetone in wastewater . Talanta Open3 100035 - 100035 2021年8月査読

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Talanta Open

It has been recently confirmed that photoexcited ketones such as acetone promote the chemiluminescence (CL) reaction of luminol and its analog, L-012. Using this finding, a selective determination method for acetone was developed herein based on HPLC separation, online UV irradiation, and subsequent luminol CL detection. Various conditions, including the type of luminol reagent, the use of organic solvents as eluent modifiers, and the reaction pH, were investigated to elucidate the CL reaction mechanism. The results showed that the CL reaction of luminol is caused by an acetone ketyl radical produced from the photoexcited acetone. The performance of the novel acetone determination method was evaluated by its application in water quality assurance in water treatment plants. The method detection limit and the method quantification limit of acetone were 0.03 and 0.08 µM, respectively. A linear range was obtained in the concentration range of 0.1–200 µM. The range of recovery in the wastewater and seawater samples (n = 5) fortified with 5.0 µM acetone was 87–108%. These results demonstrate that the new luminol CL system is useful for its sensitivity and selectivity.

DOI： 10.1016/j.talo.2021.100035

Kodamatani H., Tanisue T., Fujioka T., Kanzaki R., Tomiyasu T. . Inhibitory effect of alkyl groups on N-nitrosamine formation from secondary and tertiary alkylamines with monochloramine . Environmental Technology and Innovation22 2021年5月査読

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Environmental Technology and Innovation

N-nitrosamines are contaminants of emerging concern, and controlling these chemicals in potable water and recycled water for potable reuse has become important for protecting public health. This study aimed to evaluate the influence of the alkyl chain lengths of N-nitrosamine precursors (secondary and tertiary amines) on the formation of N-nitrosamines via chloramination. The molar conversion efficiency from dimethylamine, an N-nitrosodimethylamine (NDMA) precursor, to NDMA (0.67%) was greater than that from diethylamine, an N-nitrosodiethylamine (NDEA) precursor, to NDEA (0.38%). Similarly, the molar conversion efficiency from trimethylamine to NDMA (0.92%) was greater than from triethylamine to NDEA (0.33%). Interestingly, a considerable difference in molar conversion efficiencies were observed for tertiary amines with the N,N-dialkyl-α-arylamine structure: the molar conversion efficiencies from N,N-dimethylbenzylamine and N,N-diethylbenzylamine to NDMA and NDEA were 50.2% and 1.7%, respectively. These results indicate that amines with ethyl groups have lower potentials for producing the corresponding N-nitrosamines than those with methyl groups. These differences in yields between amines with methyl and ethyl groups can be explained by the difference in electron density in the nitrogen atom of the amine, which influences the protonation of the amine and stabilization of intermediate species. These findings could be useful for enhancing source control of water and wastewater by regulating runoff or industrial wastewater containing high concentrations of specific N-nitrosamine precursors.

DOI： 10.1016/j.eti.2021.101520

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