An electrospray ionization mass spectrometric method for the simultaneous analysis of the enantiomeric excess of free amino acids, without chromatographic separation, was demonstrated using a quasi-racemic mixture of deuterium-labelled and unlabelled chiral copper(ii) complexes. This convenient method enables the simultaneous high-sensitivity determination of the enantiomeric excess of 12 amino acids.

A series of copper(II) complexes with chiral tetradentate ligands, N,N′-ethylene- bis(S-amino acid methyl amide or methyl ester) prepared from S-alanine, S-phenylalanine, S-valine or S-proline, was generated in methanol. The copper complexes provided three component complexes in the presence of a free chiral amino acid. The enantioselectivity for the amino acid was evaluated by electrospray ionization-mass spectrometry coupled with the deuterium-labeled enantiomer method and these copper complexes were found to exhibit high enantioselectivity for free amino acids having bulky side chains. This result suggests that steric interaction between the tetradentate ligand and free amino acid was a major factor in chiral recognition. The copper complex with a chiral tetradentate ligand prepared from S-proline showed opposite enantioselectivity to copper complexes consisting of tetradentate ligands prepared from other S-amino acids. The conformational difference of the tetradentate ligand in the copper complex was found to be significant for enantioselectivity.

By using electrospray ionization mass spectrometry coupled with the use of deuterium-labelled quasienantiomers, enantioselective coordination of a free amino acid as the second ligand of a copper(II) complex with a novel chiral tetradentate ligand was evaluated quantitatively in a short measurement time.

Background: Emulsions stabilized by colloidal particles are known as Pickering emulsions. To date, soft microgel particles as well as inorganic and organic particles have been utilized as Pickering emulsifiers. Although cyclodextrin (CD) works as an attractive emulsion stabilizer through the formation of a CD–oil complex at the oil–water interface, a high concentration of CD is normally required. Our research focuses on an effective Pickering emulsifier based on a soft colloidal CD polymer (CD nanogel) with a unique surface-active property.Results: CD nanogels were prepared by crosslinking heptakis(2,6-di-O-methyl)-β-cyclodextrin with phenyl diisocyanate and subsequent immersion of the resulting polymer in water. A dynamic light scattering study shows that primary CD nanogels with 30–50 nm diameter assemble into larger CD nanogels with 120 nm diameter by an increase in the concentration of CD nanogel from 0.01 to 0.1 wt %. The CD nanogel has a surface-active property at the air–water interface, which reduces the surface tension of water. The CD nanogel works as an effective Pickering emulsion stabilizer even at a low concentration (0.1 wt %), forming stable oil-in-water emulsions through interfacial adsorption by the CD nanogels.Conclusion: Soft CD nanogel particles adsorb at the oil–water interface with an effective coverage by forming a strong interconnected network and form a stable Pickering emulsion. The adsorption property of CD nanogels on the droplet surface has great potential to become new microcapsule building blocks with porous surfaces. These microcapsules may act as stimuli-responsive nanocarriers and nanocontainers.

Structural identification of perfluoroalkyl and polyfluoroalkyl substances found in end-user products and their biodegradation products was performed using ultra-high resolution mass spectrometry. Little attention has so far been paid to the environmental burden of perfluorooctane sulfonate and perfluorooctanoic acid from compounds with a molar mass of ~2,000. Analysis of end-user waterproofing and stain repellent products revealed the presence of numerous ions with molar masses ranging from 1,000 to 2,000 and complex mass spectra. Ultra-high resolution mass spectrometry determined the accurate mass of the observed ions, allowing the cleavage position and fragment structure to be determined. The precursor structures were determined based on reconstitution of the retrieved fragments. Products of fluorochemical manufacturers before voluntary regulation comprised compounds with plural perfluorooctyl chains. In the current product lines, compounds comprising perfluorobutyl chains were detected. Biodegradation tests using activated sludge revealed that biodegradation products consistent with those reported previously were generated even from complex end-user products. For example, the biodegradation test revealed the formation of N-ethyl perfluorooctane sulfonamido acetic acid and various fluorotelomer acids in the samples. The results of the present study suggest that the environmental burden of these compounds should be reevaluated.

界面活性剤は，洗剤，塗料，トイレタリーや医薬品など様々な用途で利用されている。最近では，より優れた界面物性を有する界面活性剤，二次的な機能を有する複合機能型活性剤，あるいは，地球環境保全に配慮を加えた活性剤などの開発が望まれている。このため，界面活性剤としての本来の機能を果した後，酸や光などのできるだけ温和な外的因子を引き金として分解が起こり界面活性能が消失する機能を備えた化学分解性界面活性剤の開発に興味がもたれている。本稿では，1-O-アルキルグリセロールから1,3-ジオキソラン環を分子内に有する酸分解性カルボン酸塩型界面活性剤とエステル型化学分解性界面活性剤を特殊な試薬や装置を用いることなく，簡便な操作により合成した。これらは，良好な界面物性を有し，酸性またはアルカリ条件下で，非界面活性成分に分解した。また，微生物による生分解性は，ドデカン酸ナトリウムよりも優れていた。乳化重合反応で乳化剤として用いた場合，反応終了後，酸またはアルカリを添加することにより，乳化系を解消でき塩濃度の低い純度の高いポリマーを容易に単離することができた。さらに，洗浄力についても検討した。

Poly(butyl methacrylate) and polystyrene were synthesized by emulsion polymerization using chemocleavable anionic surfactants (1a and 2a) derived from 1-O-alkylglycerols in order to resolve the problem that it is generally difficult to isolate the desired product from persistent emulsions. It has been previously determined that 1a decomposes completely under acidic conditions whereas 2a decomposes completely under both acidic and alkaline conditions. After emulsion polymerization, the emulsions could be easily broken by adding either HCl or NaOH. Further, the polymers could be filtered off very quickly. The polydispersities of these polymers were lower than those of the polymers synthesized by conventional emulsifiers. Further, the Na content values of the former were lower than those of the latter.

Novel double-chain nonionic surfactants with an acid decomposition function were prepared by acid-catalyzed condensation of chloroacetone with fatty alcohols (octyl, decyl, and dodecyl), followed by a Williamson reaction with polyethylene glycol without any expensive reagents and special equipment. These surfactants showed easy micelle formation compared to those of polyoxyethylene (n=9) dodecyl ether (C(12)EO9), and good foaming properties. The emulsion stability of these surfactants was almost the same as that of C(12)EO9. They decomposed completely after 30 min at pH 1. After 28 days they were more than 60% biodegradable and were almost the same as sodium dodecanoate.

Chiral discrimination by novel chiral hosts 3 and 4, which consist of an oxyethylene chain and 2,3:5,6-di-O-cyclohexylidene-β-D-mannofuranose moieties at both ends, was examined considering several protonated amino acid isopropyl ester guests using fast atom bombardment mass spectrometry (FABMS) with the enantiomer deuterium-labeled guest method. Host 3 showed chiral discrimination toward several guests but with slightly smaller chiral discrimination abilities than host 2a, which consists of a bis-(oxyethylene) chain and 1,2:3,4-di-O-isopropylidene-α-D-galactopyranoside moieties at both ends. Host 4 showed no enantioselectivity, possibly because chiral hosts do not show a pseudo-ring conformation having large open spaces in complexations with a chiral guest in regard to the steric effects of cyclohexylidene groups. In addition, to understand the chiral recognition mechanisms, the binding sites of hosts 3 and 4 were elucidated by ultraviolet-visible (UV-VIS) and proton nuclear magnetic resonance (1H-NMR) spectroscopy.

The novel cyclic oligosaccharide, permethylated tetrasaccharide (CTS), determinates the enantiomers of chiral amino acid isopropyl ester hydrochlorides.

Abstract The novel cyclic oligosaccharide, permethylated tetrasaccharide (CTS), determinates the enantiomers of chiral amino acid isopropyl ester hydrochlorides.

A simultaneous estimation of the chiral discrimination abilities of several chiral hosts was demonstrated on the basis of one mass spectrum. The chiral host mixture, including H(1), H(2), H(3) ..., and H(m) (m: number of hosts) was prepared by etherification of several chiral alcohols with bistosylate of diethylene glycol. An equimolar mixture of a deuterium-labeled (S)- and unlabeled (R)-enantiomer of an amino acid isopropyl ester hydrochloride (G(S-dn) (+)Cl(-) and G(R) (+)Cl(-), n: number of deuterium atoms) was added to the chiral host mixture, and the FAB mass spectrum was measured to evaluate the chiral discrimination ability of each host in the mixture without isolation. The chiral discrimination ability of each host toward the guest is represented by the relative peak intensity of the diastereomeric complex ion pair, I(H(m) + G(R)((+)/I(H(m) + G(S-dn))(+) (=I(R)/I(S-dn) value). Several new hosts showed good chiral discrimination toward the guest.

In the human skin, four kinds of tactile receptors are distributed three dimensionally, i.e., not only on the skin surface but also in the four corresponding depths of the skin. Imitating this, a tactile sensor having four stories is proposed, inside each story of which capacitive force sensing elements are distributed in an array. The recognition method of contact state using neural networks is proposed. The stress distribution of a sensor sheet is obtained, and the outputs of the sensing elements are simulated by FEM. By applying the outputs to neural networks, it is confirmed that the contact shape recognition is possible, and the sensor having four stories achieves higher recognition rate compared with that having one story. The MEMS fabrication method of an arrayed capacitive tactile sensor made of PDMS is proposed, in which Parylene is used as an anti-stiction layer for the purpose of peeling off the PDMS sheet easily from the substrate. By stacking this sensor one by one, fabrication of a sensor having four stories is possible. A sensor having one story is preliminarily fabricated. The basic performance of one force sensing element and that of an arrayed sensor composed of 3×3 elements are characterized, which shows the potential of the proposed sensor for tactile sensing.

Following our previous report in which a capacitive ultrasonic sensor featuring a polymer Parylene diaphragm was developed by the micromachining technique, in the present study, an arrayed device comprising 5×5 sensors/transmitters was fabricated and characterized. In addition to the durability and high sensitivity due to polymer nonbrittleness and flexibility, merits attributable to Parylene, such as biocompatibility, chemical resistivity, complementary metal oxide semiconductor (CMOS) compatibility, and conformal deposition, are expected to be achieved in the future. The dispersion of sensitivity and resonant frequency of the individual sensors in the developed arrayed device was experimentally investigated. The electrical scanning of receiving directivity was performed using the arrayed device based on the delay-and-summation principle. A wide scanning angle of at least 50° was achieved. Each developed sensor was activated as a transmitter by applying an impulsive high voltage. The transmitted waveform was detectable as far as 1,000 mm away. The ultrasound was transmitted over a wide direction ranging from θ=-80 to 80°. The possibility of the electrical scanning of transmitting directivity was preliminarily confirmed using the arrayed device.

The present paper reports the development of a capacitive ultrasonic sensor having Parylene diaphragm. Parylene diaphragm is flexible and non-brittle, allowing good sensitivity and durability. The resonant frequency under the tensile stress of Parylene and the influence of the number and the radius of acoustic holes on damping ratio are investigated by FEM simulation. Practical sensor devices are fabricated. They can receive an impulsive ultrasonic pulse transmitted by a spark discharge. The ranging system using this sensor can detect the distance up to 1 m with the error less than 1 mm. The developed sensor can be approximated to be non-directional.

In human skin, four kinds of tactile receptors (Meissner corpuscle, Merkel cell, Ruffini ending, and Pacinian corpuscle) are distributed three dimensionally, i.e., not only on the skin surface but also in the four corresponding depths of the skin. The final goal of this study is achieving a flexible tactile sensor having four layers imitating human skin. An array type tactile sensor made of PDMS, which is a kind of silicone rubber, is developed by MEMS technology. By stacking this sensor one by one, fabrication of a multilayer type sensor is possible in future. In this report, the concept of this sensor is proposed, an array sensor of one layer is fabricated, and the performance of one capacitive force sensing element is characterized preliminarily.

The final goal of this research is to develop a condenser type micro ultrasonic sensor, which would be used as both receiver and transmitter. Polymer diaphragm is flexible and non-brittle, allowing good sensitivity and durability. Besides that, Parylene has good C-MOS compatibility, since it can be deposited at room temperature. Based on the FEM simulation results on the resonant frequency under tensile stress of Parylene, the diaphragm radius of 500〜1200 μm is employed to realize the bandwidth up to ultrasonic range of 40〜100 kHz. The influence of the number and the radius of acoustic holes on damping ratio is investigated by FEM simulation, in order to achieve a moderate damping of the diaphragm. Practical sensor devices are fabricated. They can receive an impulsive ultrasonic pulse transmitted by a spark discharge. The open-circuit sensitivity is 0.3 mV/Pa, in reference to B&K 4138 microphone. The ranging system using this sensor can detect the distance up to 1 m with the error less than 1 mm. The developed sensor can be approximated to be non-directional.

New dithiocarbamate surfactants 2 (potassium N-2-[2-(2-methoxyethoxy)ethoxy]ethyl-N-dodecyldithiocarbamate), 3 (potassium N-2-(2-alkoxyethoxy)ethyl-N-dodecyldithiocarbamate; a, alkoxy=C6H13O; b, alkoxy=C8H17O), and 4 (potassium N-2-decoxyethyl-N-dodecyldithiocarbamate), as well as 5 (potassium N,N-didodecyldithiocarbamate) were prepared. The synthetic route to 2–4 is a useful, general alternative to that reported for related surfactants. The molecular compositions of 2–5 were confirmed by combustion analyses and electrospray mass spectrometry, and their structures were established by 1H and 13C NMR spectroscopy. Surfactants 2–5 in water were characterized by Krafft temperature, solubility, and critical aggregation concentration measurements, and aggregated surfactants were characterized by dynamic laser light scattering. Surfactant 2 forms micelles in water, in contrast to 3–5, which form vesicles.