Infrared absorption and Raman scattering are well known as complementary measurement methods, but this complementarity generally breaks down below a few cm⁻¹ (about 100 GHz). For infrared and Raman to be complementary, it is necessary that discrete energy levels are determined when the vibrational modes are treated quantum mechanically. Breakdown of the complementarity means that the energy levels are continuous. Spectral assignment based on the infrared and Raman selection rules is limited to regions of tens of cm⁻¹ (about 1 THz) or more.

Under the Act on Special Measures against Dioxins, local governments are analyzing public water and air to investigate the effects of dioxins. Atmospheric deposition is also considered an important factor in assessing the environmental impact of dioxins, but there are few reports of studies on this issue. Once the deposition rate of dioxins is known, the amount of atmospheric deposition flux of dioxins can be estimated from the air monitoring results. In this study, deposition velocities were calculated for each major source of dioxin contamination in Japan using indicative congeners. The results showed that the average deposition velocities of combustion- and pentachlorophenol-origin dioxins were 0.15 cm s⁻¹ and 1.7 cm s⁻¹, respectively. The different deposition velocities by contamination sources may be due to the behavior of the particles to which the dioxins are attached.

In this study, a purge and trap (PT) method was employed to quantify seven volatile methylsiloxanes (VMSs) in fish samples. The clean-up conditions for the fish extract were optimized, resulting in method detection and quantitation limits across a series of analyses ranging from 0.3 to 0.8 ng g⁻¹ wet weight (ww) and from 0.8 to 2.6 ng g⁻¹ ww, respectively. To evaluate the effectiveness of the developed method, it was applied to analyze fish samples from both river and marine environments, demonstrating its applicability for samples with lipid content of up to approximately 15 %. The total concentrations of VMSs in the fish samples ranged from 4.7 to 10300 ng g⁻¹ ww, with D5 being the predominant compound. The highest concentration was found in the fish sample collected near a sewage treatment plant discharge. The ranges of bioaccumulation factors for most VMSs overlapped or exceeded the high bioconcentration criteria, suggesting these compounds possess a high bioaccumulation potency. This is the first study to report VMS occurrence in fish samples from the Japanese river environment.

Anionic surfactants are among the water quality test items under the purview of the Water Supply Act. The provision of mixed standard solutions of five types of alkylbenzene sulfonates (ABS) within the Japan Calibration Service System (JCSS) has been desired. However, achieving SI traceable characterization has been challenging due to the target analytes being ABS with varying alkyl chain lengths (C10-C14) and each ABS being a mixture of structural isomers. In this study, we developed an SI traceable characterization method for the total concentration of each ABS isomer, leveraging their uniform molar absorptivity. Additionally, we developed a method to accurately characterize mixed solutions (Secondary standard solutions) using mixed solutions (Specified standard solution: Primary standard solution in the Measurement Act) with peak area corrections derived from single-component solution measurements. The JCSS anionic surfactant mixture standard solution supplied by this method is reliable for use as calibration solutions in the measurement of water quality standards under the Water Supply Act.

The bromine (Br) and iodine (I) content of geological samples can be used to understand various environmental phenomena such as past sea-level changes, geological uplift and subsidence, as well as marine incursion to the inland due to paleo tsunamis and storm surges. Wavelength dispersive X-ray fluorescence spectrometry (WDXRF) and energy dispersive X-ray fluorescence spectrometry (EDXRF) have been recognized as robust methods for the determination of the elemental composition of geological samples and a wide range of materials in research and technical fields, such as the chemical analysis of cultural properties, industrial and waste materials. However, determining Br and I content has been difficult due to the relatively low concentrations of these elements in geological samples and the limited number of reference materials for XRF analyses. Despite this, the polarizing EDXRF (Epsilon5, Malvern Panalytical) at Tohoku University produced sufficient results for determining the Br and I content of geological samples. In this study, we measured the Br and I content of possible standard materials and lake sediment samples using WDXRF at the Japan Atomic Energy Agency and polarizing EDXRF at Tohoku University. We compared the both results and confirmed that the WDXRF method can reliably determine Br and I content. In the future, we aim to develop a quantitative analysis of trace amounts of Br and I in solid samples through the identification and development of standard materials.

Sodium alkylbenzenesulfonates (ABS) have been used as reference materials for the analysis of anionic surfactants in tap and environmental waters. In this study, we developed a method to quantify the total amount of benzenesulfonic acids in solution based on the molar absorption coefficients of the analogues. After confirming the same absorption spectra among the analogues, we quantified LAS and ABS at approximately 1000 mg L⁻¹ using linear dodecylbenzenesulfonic acid (12C-LAS), then we compared these results with those obtained by quantitative ¹H NMR. To validate ABS quantification, we compared results from two laboratories. The results for all target compounds agreed with the reference values within a range of approximately 2 %, and the difference between the two laboratories was approximately 1 %. Considering concentration dependence and peak shapes as sources of uncertainty, the relative value of the expanded uncertainty was less than 6 % for the alkylbenzenesulfonate standard solution at approximately 1000 mg L⁻¹, which should be acceptable for routine analyses of anionic surfactants in tap and environmental waters.

There are concerns that certain phthalates may have adverse effects on human health. The Restriction of Hazardous Substances in Electrical and Electronic Equipment (RoHS) Directive stipulates maximum allowable concentrations for four specific phthalates. To control the concentrations of these phthalates, it is crucial to validate the analytical methods used, typically through reference materials. Polyvinyl chloride (PVC), a certified reference material (CRM) issued by the National Metrology Institute of Japan (NMIJ)/the National Institute of Advanced Industrial Science and Technology (AIST), contains these four restricted phthalates. However, diisobutyl phthalate (DIBP) lacks a certified value. To establish a certified value for DIBP, we applied isotope dilution mass spectrometry (IDMS). We determined the mass fraction of DIBP in PVC (891 mg/kg, NMIJ CRM 8152-b(02); 91 mg/kg, NMIJ CRM 8156-a(02)) using a DIBP calibration material, whose purity was evaluated by quantitative nuclear magnetic resonance (qNMR) spectrometry. This approach is expected to facilitate the proper management of these restricted phthalates in the PVC CRMs.

Countries around the world have committed to achieving carbon neutrality, with Japan setting 2050 as its target year. Efficient utilization of organic carbon resources such as petroleum, biomass, and waste plastics is crucial to achieving this goal, placing significant emphasis on research and development. The authors are primarily engaged in developing pyrolysis processes to convert waste plastics and biomass into chemical feedstock and have proposed various applications of pyrolysis gas chromatography (Py-GC) to investigate pyrolysis products and behavior in detail. This paper introduces in-situ analytical methods for pyrolysis-catalysis reactions using tandem-μ-reactor-gas chromatography, in-situ methods for high-boiling-point pyrolysis products through pyrolysis-gas-phase derivatization-GC/MS, in-situ analysis of combustion reaction products from super engineering plastics, and the development of Py-GC/multi-detector systems.

Cholesterol is an important component of cell membranes and a precursor of steroid hormones. However, it causes hyper-LDL-cholesterolaemia in dyslipidaemia, a lifestyle-related disease. Therefore, the quantification of plasma cholesterol is important for determining the pathological conditions and efficacy of therapeutic agents. However, lipids, such as cholesterol, which are highly fat-soluble in the blood, are incorporated into lipoproteins; making their extraction difficult. Measurement of cholesterol, its precursors, plant sterols, cholestanol, and oxysterols in plasma are useful for diagnosis of inherited disorders of cholesterol biosynthesis, malformation syndromes, familial hypercholesterolemia, cerebrotendinous xanthomatosis, and sitosterolemia, as well as for evaluating the effects of drug administration. In this study, a highly accurate and sensitive method was developed for determining cholesterol biosynthesis, absorption, and metabolites (oxysterols). The developed method was applied to patient blood samples to discover new activities of the dyslipidemic drug ezetimibe (enhancement of cholesterol biosynthesis as a compensatory effect on cholesterol absorption and inhibition of 7β-hydroxycholesterol absorption). Additionally, cerebrotendinous xanthomatosis and sitosterolemia were identified as biomarkers of the disease. Moreover, 24S-hydroxycholesterol (24OHC) was identified as a potential marker of central nervous system disorders in phenylketonuria, and the increase in 24OHC levels in the brain due to growth hormone administration in small-for-gestational-age patients was measured. Additionally, an association between cardiovascular risk factors and oxysterol concentrations in patients with type 2 diabetes mellitus was observed. On further application to cell culture and animal experimental systems, it was found that ergosterol in mushrooms, daidzein in soya and lactic acid bacteria have an inhibitory effect on cholesterol biosynthesis by inhibiting the downstream of cholesterol biosynthesis pathway.

The phosphorus (P) concentration in Australian iron ore is expected to increase in the future. In order to effectively utilize these high-P Australian ores. A new dephosphorization process must be introduced into the existing operational process. To accomplish this, it is necessary to analyze the chemical structure of phosphorus adsorbed goethite in iron ore, a topic that has not been reported on before. In this study, we analyzed the chemical structure of phosphorus adsorbed goethite in iron ore using infrared spectroscopy and quantum chemical calculations. We found that IR spectrum of phosphorus adsorbed goethite in the solid state changes depending on the pH of the solution containing it. In an acidic solution, the phosphorus adsorbed goethite exists as monodentate FePO₂(OH)₂ and FePO₃OH. Conversely, when the solution is neutral or basic, the phosphorus adsorbed goethite exists as monodentate FePO₃OH, similar to previous reports. We also found that the phosphorus adsorbed goethite contained in two types of Australian high-P ores exists as monodentate FePO₂(OH)₂ and FePO₃OH. Since the ratio of these chemical structures differs for each type, we inferred that the two types of iron ores formed under different conditions. This information is useful for optimizing dephosphorization conditions and in the selection iron ore that is useful for operation. Utilizing this information, we can expand the use of high-P iron ore.

This paper describes the simultaneous determination of both pharmacologically active bodies and its counter ions in active pharmaceutical ingredients (APIs) in one HPLC analysis. Organic acids such as maleic acid (MA) and fumaric acid (FA) used as counter ions of APIs have no retention in the usual reversed phase HPLC mode that is most typically used for the purity test and assay of APIs, and these elute at the holdup time (t₀). By employing HILIC mode HPLC where a mixture of relatively high concentration ratio acetonitrile (ACN) and low concentration buffers (aqueous solutions) is used as the mobile phase, organic acids such as MA and FA showed retention of pharmacologically active bodies in APIs. In this study, a β-cyclodextrin (CD) immobilized column and a diol column were used as hydroxy type HILIC columns. Separation of various organic acids such as MA, FA, hybenzic acid, salicylic acid, etc., was successful by these columns employing high ACN% (70-85 %). Retention times of these organic acids increased with an increase of ACN%, indicating HILIC mode was at work. On the other hand, retention times of pharmacologically active bodies in APIs were not significantly affected by ACN% in the investigated range, showing ionic interaction (adsorption) was at work. Other than the concentration of ACN, the buffer concentration affected retention of both pharmacologically active bodies and its counter ions in APIs. With an increase of the buffer concentration, retention of counter ions increased and vice versa, retention of pharmacologically active bodies decreased. Counter ions in APIs were successfully determined by the internal standard method. This paper shows that the HILIC mode can be used as an identification method of both the counter ion and the pharmacologically active body in API through the matching of retention times (or relative retention times). Additionally, the stoichiometric ratio of the counter ion in APIs can be evaluated by the developed HILIC mode.

This paper describes the development of the fast quality evaluation method of berberine (BE) by employing various core-shell (CS) type reversed-phase columns. BE is a famous pharmacologically active ingredient found in Phellodendri Cortex and Coptidis Rhizoma, with both having been included in the Japanese Pharmacopoeia (JP). HPLC methods with a C18 column and a mobile phase using sodium dodecyl sulfate (SDS) have been used in the JP method (official method) for the assay of BE in these crude drugs. This HPLC method using a C18 column and an SDS buffer is useful for the determination of active ingredients (e.g., alkaloids) in various Kampo products. However, equilibration of the column takes time for the use of the SDS buffer in the C18 column. In this study, quality evaluation of BE was investigated by employing various core-shell (CS) type reversed-phase columns from the viewpoint of separating BE and palmatine (PA). PA is another pharmacologically active ingredient contained in Phellodendri Cortex, which is used as a substance to confirm the column selectivity in the JP method. The necessity of ion-pair reagents was also examined. In the most used C18 columns, as in SDS, sodium octanesulfonate was effective for the peak shape and resolution for these basic analytes. Of the four organic solvents investigated as organic modifiers — methanol, acetonitrile (ACN), dioxane, and tetrahydrofuran (THF) — THF was found to be extremely effective at separating BE and PA in C18 columns. This led to the fast quality evaluation of BE, BE in powdered Phellodendri Cortex and in Kampo extract granules containing Phellodendri Cortex. Apart from this, a biphenyl type column with ACN as an organic solvent was also found to be extremely effective at separating BE and PA. The fast separation of BE, PA, and the other major related substance, estimated to be jatrorrhizine, was completed in 2 to 3 minutes.

It difficult to elucidate functional mechanisms and ensure performance when evaluating devices under high temperature and humidity conditions solely through samples extracted in normal environments. This study developed a novel heating and humidifying chamber with a control system that enables in-situ synchrotron radiation analysis under these conditions. We evaluated the chamber’s performance and conducted in-situ measurements using iodine-containing polyvinyl alcohol films. X-ray absorption spectra were measured from room temperature to 80°C and from 0 % to 80 % relative humidity. Unlike conventional room temperature humidification, this method allows for realistic high temperature and humidity measurements.

The partition coefficient between 1-octanol and water (log P_ow) is a physicochemical property used to predict the bioaccumulation and toxicity of chemicals; however, an experimental method to measure the log P_ow of surfactants has yet to be established due to the problem of emulsion formation. It has been reported that the slow-stirring method can be used to measure the log P_ow of surfactants because it effectively avoids emulsion formation. However, a few studies have shown that the log P_ow of surfactants depends on initial concentration, even when it is below the critical micelle concentration (CMC). In this study, we investigated factors affecting log P_ow, such as initial concentration, using various surfactants. As a result, we found that the log P_ow of some surfactants was independent of concentration below the CMC. This indicates that optimizating the initial concentration based on the CMC is important when applying the slow-stirring method to surfactants. Notably, in one case, log P_ow decreased due to the formation of an O/W emulsion in the aqueous phase when the initial concentration was relatively high.

Pulsed NMR is an effective measurement method for evaluating the physical properties, degradation phenomena, and reliability of materials. Many Free Induction Decay (FID) signals observed in materials with complex components, such as polymer blends, are due to multiple relaxation processes. When signals contain multiple relaxation processes, it is important to separate them to accurately evaluate physical property information. Since FID signals decay exponentially from the maximum value of the magnetization intensity, it becomes difficult to distinguish and detect the noise floor components mixed in the equilibrium state. In this study, we applied a filtering process to the FID signal that, in principle, can remove the noise floor components contained in the FID signal and focus on the point at which the magnetization intensity peaks. We demonstrated that the relaxation time and maximum magnetization intensity according to the arbitrary Weibull coefficients of the FID signal can be evaluated from the detected peak time. Furthermore, we propose an analytical method that can directly visualize the relaxation time from the filtered FID signal. As a result, it became possible to separate signals from the visualized distribution of relaxation times. The validity of this analytical method was confirmed by the separation of the filtered FID signal measured on a PVDF film.