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The asymmetric transfer hydrogenation of α,β-unsaturated aldehyde with Hantzsch ester catalyzed by polymer-supported chiral pyrrolidine organocatalyst was achieved. The effects of the pyrrolidine s...

Liquid water exhibits many anomalous physical properties because of its unique structure and hydrogen bonding networks, which were mostly uncovered at the beginning of the 20th century. Because of ...

Diphenylprolinol silyl ether is a widely used organocatalyst, and its immobilization on a solid support was investigated for the easy recycling and reuse of this catalyst. Because a silyl ether bon...

We have developed palladium-catalyzed C–H activation and cyclization of alkynyl ferrocenyl ethers with various alkynes, providing ferrocene-fused pyran derivatives. As a preliminary result, we also achieved the asymmetric version of this reaction with high enantioselectivity, providing the first example of the catalytic asymmetric synthesis of an enantio-enriched ferrocene-fused oxacycle.

Aiming at fabrication of hybrid plasmonic-photonic crystals, gel-immobilized colloidal crystals made of a polystyrene colloidal suspension and an N-(Hydroxy methyl)acrylamid-based gel were immersed into an aqueous dispersion of gold nanoparticles. Atomic force microscope (AFM) observations have been performed for the gel-immobilized colloidal crystals with gold nanoparticles deposited on their surfaces. In the present study, the diameter of a colloidal sphere was c.a. 190 nm. The diameter of a gold nanoparticle was the same as in a preliminary study, c.a. 40 nm. Various immersion times up to two hours were tested. Surface of a sample of 2 hr immersion has been observed. Prior to the AFM observation, the sample was dried in a desiccator for 18 hrs. We have identified a face-centered cubic {111} structure of a colloidal crystal of nearly close packing. Nanoparticles isolated with one another have been observed on the surface of gel-immobilized crystal, which can be regarded as gold nanoparticles from their sizes., 29 pages, 8 figures, 1 table; Bulletin of Chemical Society of Japan, accepted

It is known that an achiral water-soluble polythiophene (PT-1) is chirally twisted by complexation with a natural helix-forming polysaccharide, shizophyllan (SPG). We found that the chirality can b...

Chemical speciation of arsenic species in human blood serum was performed by high-performance liquid chromatography/inductively coupled plasma mass spectrometry (HPLC/ICP-MS) with direct sample inj...

A multiply hyphenated HPLC/UV/ICP-MS system equipped with a fraction collection valve for subsequent MALDI-TOF-MS analysis was constructed, and its applicability to the speciation of metalloprotein...

An octadecylsilyl silica (ODS) column coated with phosphatidylcholine (PC) was prepared by using a dynamic coating method, and its separation characteristics were evaluated for direct sample inject...

Assay of alkaline phosphatase (ALP) in salmon egg cell cytoplasm was performed by size exclusion chromatography (SEC) with fluorescence detection of enzymatic activity and element-selective detecti...

The concentrations of major-to-ultratrace elements in bittern, which was obtained after seawater concentration in the salt preparation process, were investigated by ICP-AES (inductively coupled pla...

The multielement determination of precious metals (Ru, Rh, Pd, Ir, Pt, and Au) in industrial waste incineration ashes was examined by inductively coupled plasma mass spectrometry (ICP-MS) with exte...

Chemical speciation of arsenic in human urine was performed by HPLC separation with ICP-MS detection in order to investigate the urinary excretion patterns of arsenic metabolites after one-time ingestion of an edible seaweed, hijiki (Hizikia fusiforme). A Japanese male volunteer ingested one serving of ca. 15 g (dry weight) of hijiki (containing ca. 0.9 mg of arsenic), and urine samples were collected at 3-5 h intervals for the following 3 days. As a result, different urinary excretion patterns were observed between inorganic and methylated arsenicals. Toxic inorganic As(V) and As(III) were detected in the urine 3 h after ingestion. The highest concentrations of As(V) and As(III) were observed at 6 and 15 h after ingestion, respectively. In contrast, methylated arsenic species in the urine, such as monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and arsenobetaine (AB), began to increase 10 h after ingestion and provided the highest concentrations at 21 h after ingestion. These results indicate that a large amount of As(V) from hijiki is excreted rapidly in urine and some part of it is reduced to As(III) in the human body. As(III) may then be converted to non-toxic methylated arsenic species and excreted in urine later than inorganic ones. It can be concluded from these experimental results that detoxification of arsenic occurs in the human body through the rapid urinary excretion of toxic arsenicals or by conversion to organic methylated ones after ingestion of hijiki.

A tandem preconcentration method using a chelating resin was exploited for simultaneous multielement determination of trace metals in seawater by inductively coupled plasma mass spectrometry (ICP-M...

A chelating resin-packed minicolumn was developed to pretreat seawater samples for the determination of trace metals by inductively coupled plasma mass spectrometry (ICP-MS). The preconcentration conditions, such as the flow rate of sample loading, pH for adsorption, amount of ammonium acetate for eliminating matrix elements, and the amount of nitric acid for eluting trace metals from the resin, were investigated and optimized. Firstly, 50 mL of seawater samples was adjusted to pH 6.0 and loaded into the column at the flow rate of 3 mL min - 1 . Secondly, 8 mL of 1 M ammonium acetate and 5 mL of pure water were passed through the column for eliminating matrix elements, such as Mg and Ca. Finally, trace metals were eluted with 2.25 mL of 2 M nitric acid, and then 0.25 mL of internal standard elements (Ge, In, Re, Tl, 100 μg L - 1 each) was added to the eluted solution in order to correct matrix effects in the ICP-MS measurements. The recoveries for 23 elements (Mn, Co, Ni, Cu, Zn, Y, Cd, all-REEs, Pb, and U) were more than 80%. The analytical results for the concentrations of trace metals in seawater reference material (NASS-5) agreed well with certified or reference values. The present method was also applied to the multielement analysis of the coastal seawater samples from the Take Island (Gamagoori, Aichi prefecture, Japan) and the Ise Bay (Nagoya, Aichi prefecture, Japan).

Coastal seawater and river water samples were collected near Nagoya port, located in the coastal area of the Ise Bay, and in six rivers around Nagoya City. The rare earth elements (REEs) in these samples were determined by inductively coupled plasma mass spectrometry (ICP-MS) with chelating resin preconcentration. The concentrations of all REEs except for Pm in coastal seawater and river water samples could be determined at the concentration level from sub-ng L - 1 to 10 ngL - 1 . In order to examine the relative concentration variations, the REE patterns were estimated by normalizing the concentrations of REEs in the water samples to those in Post Archean Average Australian Shale (PAAS). Significantly positive Gd anomalies in the REE patterns were observed for river waters down from the urban areas as well as for coastal seawater. Such Gd anomalies were especially remarkable for river water collected near sewage treatment facilities in the Tenpaku river. It was, thus, concluded that the Gd anomalies in the REE patterns were artificially caused by anthropogenic sources mainly due to recent use of a gadolinium compound as a contrast reagent for magnetic resonance imaging (MRI) in medical diagnosis.

The leachabilities of major-to-ultratrace elements in industrial waste incineration fly ash (IWIFA) were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) in order to characterize IWIFA. The leaching data of about 50 elements in the IWIFA sample could be obtained in the concentration range from mg g-1 to sub-µg g-1, when HNO3 and aqua regia were used as the leachants. In addition, morphological observations of IWIFA particles were performed by a scanning electron microscope with an energy dispersive X-ray spectrometer (SEM-EDS) before and after the leaching treatment of the IWIFA samples. From the data for the leaching and morphological observations, the chemical states of the elements in IWIFA were elucidated as follows: (i) core materials of fly ashes were mostly composed of stable oxides of major elements such as Si, Al, Ti, and Fe; (ii) Cu, Zn, Mo, Cd, and Bi were mainly adsorbed on the surface of fly ash particles...

The multielement determination of major-to-ultratrace elements in industrial waste incineration bottom ash was carried out by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) after alkali fusion using LiBO2. The concentrations of 50 elements in bottom ash could be determined over the concentration range from 192 mg g−1 of Si to 0.072 μg g−1 of In. Silicon, Al, Fe, Ca, Na, and Ti, which except for Fe are lithophile elements, were major elements of industrial waste incineration bottom ash. The distributions of major-to-ultratrace elements in incineration bottom ash were evaluated by the enrichment factors. The enrichment factors of major elements in incineration bottom ash indicated that their relative contents were quite similar to those in the continental crust. It was also found that most minor and trace elements in the lithophile element group provided almost the same enrichment factors as those of major elements. On the other ha...

A tandem preconcentration method, in which chelating resin adsorption and La coprecipitation were cooperatively employed for preconcentration, was developed as a pretreatment method for simultaneous multielement determination of trace elements in seawater by ICP-MS. First, the seawater sample (250 ml) was treated with a chelating resin for preconcentration of trace elements, and then trace elements with good recoveries were determined by ICP-MS. Trace elements with the chemical properties of oxoanion- and hydride-formation, which were poorly recovered in the chelating resin preconcentration, were further subjected to preconcentration by La coprecipitation. As a result, more than 30 elements could be determined in the concentration range from 9.6 μg L-1 for Mo to 0.00018 μg L-1 for Tm, when the present tandem method was applied to the analysis of open seawater standard reference material (NASS-4). Furthermore, the analytical results for open seawater reference materials were compared with those for coastal...

The coastal seawater sample was filtered with a membrane filter (pore size 0.45 μm), and the filtrate was further filtered with an ultrafiltration filter (molecular weight permeation limit of 10000 Da). Then, major-to-ultratrace elements in the particles which remained on the membrane filter, the membrane-filtered seawater, and the ultrafiltered seawater were determined by ICP-AES (inductively coupled plasma atomic emission spectrometry) and ICP-MS (inductively coupled plasma mass spectrometry). From these analytical results, the fractional distributions of each element in the particle, large molecule and small molecule fractions of seawater were estimated, where the distributions of the elements in the large molecule fraction were obtained as the differences between the elemental concentrations in membrane-filtered and ultrafiltered seawaters. Furthermore, laboratory-made salts (Salts I—III) were prepared from original, membrane-filtered, and ultrafiltered seawaters. The concentrations of major-to-ultrat...

The simultaneous multielement determination of trace elements in seawater, especially hydride- and oxoanion-forming elements, has been investigated by inductively coupled plasma mass spectrometry with the aid of lanthanum coprecipitation preconcentration. The optimum pH in lanthanum coprecipitation was pH 9.5; at this value, trace elements were well recovered and major constituents of seawater such as Na, Mg, K, and Ca were significantly reduced in the concentrated solutions. The recovery values obtained for V, Cr(III), Mn, As(III), As(V), Se(IV), Y, Sn, Sb(III), Sb(V), W, Bi, and U were more than 85% after lanthanum coprecipitation, while Cr(VI), Se(VI), and Mo(VI) provided poor recoveries of less than 30%. The reproducibility for coprecipitation was within 5% as relative standard deviation. The present method was applied to the determination of trace elements in coastal seawater reference material CASS-3. The analytical values for Mn, As, V, Y, Sb, W, and U were in fairly good agreement with the certifi...

The multielement determination of trace elements in coastal seawater by inductively coupled plasma mass spectrometry has been investigated with the aid of chelating resin preconcentration. First, each coastal seawater sample (250 ml) was treated with a chelating resin (Chelex 100) at pH 6 for preconcentration of trace elements. After filtration with a glass filter, the resin on the filter was carefully rinsed with 8 ml of 1 M ammonium acetate solution. Then, trace elements adsorbed on the resin were eluted with 6 ml of 2 M HNO3. As a result, the preconcentration factor of 41.7 fold was obtained, with the total concentration of matrix elements (Na, K, Mg, and Ca) less than 200 mg dm−3. The recovery values were larger than 80% for 22 elements among 29 elements determined. The present method was applied to the determination of trace elements in the coastal seawater certified reference material CASS-3, issued from National Research Council of Canada (NRC), as well as to the coastal seawater sample collected f...

The progress of modern analytical atomic spectrometry is briefly reviewed with emphasis on ICP-AES and ICP-MS; these provide some excellent analytical features such as high sensitivity, wide linear dynamic range, and multielement detection capability. Thus, the multielement determination of the major-to-ultratrace elements from % to sub-ppt (1 ppt = 10−12 g ml−1) level is possible for the biological, geochemical, and environmental samples. The standard or certified reference materials of plant, human blood serum, and the other biological samples were analyzed to establish the reliable analytical methods for the multielement determination by ICP-AES and ICP-MS. The modern analytical methods were applied to: (i) the correlation analysis of the elements in human blood serum, and (ii) the determination of rare earth elements in human blood serum on a personal basis. The speciation of trace elements in natural water was also carried out by the SEC (size exclusion chromatography)/UV absorption detection/ICP-MS ...

An on-line separation-detection system, liquid chromatography coupled with inductively coupled plasma mass spectrometry (ICP-MS), has been developed and applied to the study on speciation of trace metals in pond water. First, the total concentrations of dissolved metal ions in pond water were determined by ICP-MS after chelating resin preconcentration. Then, pond water was preconcentrated by ultrafiltration using a filter with a molecular weight permeation limit of 10000, providing size exclusion chromatography. Large organic molecules which had combined with trace metals in the preconcentrated samples were separated with a gel filtration column and detected by UV absorption and ICP-MS, sequentially. In consequence, large organic molecules with the molecular weight of ≥300000 and 10000—50000 could be observed. A large number of trace metals (41 elements) were found in those organic molecules. Furthermore, the percentages of metal ions in the forms of large organic molecule–metal complexes were estimated f...

A discrete microsampling technique for multielement determination of trace elements by inductively coupled plasma mass spectrometry has been investigated for analyses of samples containing large amounts of matrix elements. In the technique, 100 μl of the sample solution was introduced into the plasma by using a six-way valve, and 10 elements were detected in peak hopping mode during a single mass range scan. As a result, a transient peak profile of the signal for each element was observed at each m/z position. The peak area measurement method was established for the quantitative analysis. The optimization of instrumental conditions and matrix effects in multielement determination were investigated in detail. The discrete microsampling technique was found to reduce some memory effects due to matrices in ICP-MS. The present system was applied to the analyses of standard sediment sample and 30 elements at the μg g−1 level were successfully determined without matrix separation.

An analytical method for multielement determination of trace and ultratrace elements in seawater has been investigated by using ICP-MS. Trace and ultratrace elements were preconcentrated by 10- or 20-times with addition of aluminum into seawater and then the elements were determined by ICP-MS. In this procedure, aluminum was added as the carrier for coprecipitation; it precipitated together with magnesium in seawater. Some trace elements were also measured by ICP-AES after coprecipitation. In addition, major and minor elements in seawater were determined by ICP-AES after dilution with acidified water. As the result, 37 elements in total could be determined in coastal seawater. The present results are compared with the concentrations of the elements in open seawater.

Rare earth elements in coastal seawater were preconcentrated by using chelating resin in a batch method and determined simultaneously by inductively coupled plasma mass spectrometry (ICP-MS). In this procedure, matrix components (Na, K, Mg, and Ca) were eliminated to reduce matrix effects in ICP-MS analysis and rare earth elements were concentrated by a concentration factor of 100. The pH dependence of the recovery, resin amounts, amount of ammonium acetate for washing, and elution of adsorbed metals with nitric acid were examined in details to optimize the experimental conditions in sample pretreatment. All rare earth elements in coastal seawater were determined at the ppt or sub-ppt level successfully by the present analytical method.

A hyphenated system of inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) combined with aid of optical fiber was developed for versatile simultaneous multielement measurement of the elements from the major to ultratrace levels. In the present system, the emission signals from the argon ICP equipped for ICP-MS were led through optical fiber to a sequential-type monochromator for ICP-AES measurement. In consequence, the dynamic range of 9 orders of magnitude from a few pg ml−1 up to ca. 1000 μg ml−1 was obtained, which allowed the simultaneous determination of a variety of elements in the wide concentration range by ICP-MS and/or ICP-AES. The present system was applied to simultaneous multielement analysis of rock and seawater samples.

The rapid determination of rare earth elements (REEs) has been investigated by an on-line system of high performance liquid chromatography/multichannel inductively coupled plasma atomic emission spectrometry. In the present system, all REEs could be detected simultaneously in a single chromatographic measurement without spectral interferences. Utilizing a cation exchange column and 2-hydroxy-2-methylpropanoic acid aqueous solution as the mobile phase, the detection limits of 0.4—30 ng ml−1 for all REEs were obtained. The system was applied to the determination of REEs in geological standard rock samples and rare earth impurities in high purity rare earth oxides. The REEs in standard rocks could be determined by the present HPLC/ICP-AES system without pretreatment after acid digestion, although the detection limits were not sufficient for the analysis of rare earth oxides.

We investigated the effect of halogen substitution of N-alkylcarbonyl-N-phenylhydroxylamines on the extraction of lanthanoids(III). A p-chloro substituent of a phenyl group increased the acidity of R-PHAs by 0.3—0.5 pKa units, and a bromo substituent on the α carbon of the acyl group increased it by 1.5 pKa units. In the former substitution, the separation factor for pairs of lanthanoids(III) and yttrium(III) remained unchanged, whereas in the latter the separation factor was considerably reduced. Hence, the chloro substitution at the phenyl group was a good choice for lowering pH values in the extraction of lanthanoids(III). The pH region was suitable for extracting lanthanoids(III) while preventing the formation of their hydroxo complexes.

Lanthanoids(III) and yttrium(III) were extracted with N-(2,2-dimethylvaleryl)-N-phenylhydroxylamine (DV-PHA) having a tertiary alkyl group attached to the carbonyl group. The distribution ratio of a lanthanoid(III) ion between the carbon tetrachloride and the aqueous phases was measured as functions of the pH and DV-PHA concentration at 298 K and an ionic strength of 0.1 (NaNO3). The aqueous phase involved sodium tartrate (1.0 × 10−2 mol dm−3). Lanthanoids(III) were extracted as a self-adducted chelate, ML3(HL)3, with DV-PHA (HL). The separation factors for pairs of Yb/Eu and Yb/Y were considerably greater than those of bis(2-ethylhexyl)hydrogenphosphate. The excellent selectivity of DV-PHA was attributable to a greater inductive effect of the tertiary alkyl group than those of the primary and secondary alkyl groups.

The distribution constants of 2-(2-pyridylazo)phenol (PAP), 2-(2-pyridylazo)-5-methylphenol (PAP-5Me), and metal chelates with PAP and PAP-5Me between aqueous micellar psuedophases were evaluated in aqueous micellar solutions of Triton X-100. The distribution constants were found by measurement of equilibrium shifts in acid-base and complexation reactions in the presence of micelles at an ionic strength of 0.1 ((Na+, H+) ClO4−) and at 293 ± 1 K. The metal chelates (vanadium(V), nickel(II), and iron(II)) had a linear correlation between their logarithmic distribution constants and their van der Waals volumes. PAP and PAP-5Me had a different kind of correlation from the metal chelates did. These results were explained by the difference in the part of the micelles into which hydrophobic chelates and hydrophilic chelating reagents were incorporated.

A novel method for enantiometric separation using an ODS stationary phase coated with bile salt micelles in high-performance liquid chromatography has been developed, where bile salt surfactants such as sodium cholate and sodium deoxycholate were used for micelle formation. The present method was applied to the separation of the enantiomers of 1,1′-binaphthyl-2,2′-diyl hydrogenphosphate (BNDHP) and N-dansylphenylalanine by using acetonitrile–water solution as the mobile phase. The dependence of the capacity factors and separation factors on the acetonitrile concentration in the mobile phase was examined for BNDHP enantiomers. These factors decreased with increasing acetonitrile concentration, which resulted in the change of separation characteristics of BNDHP enantiomers. Although BNDHP and N-dansylphenylalanine enantiomers were separated, similar enantiomers such as 2,2′-dihydroxy-1,1′ -binaphthyl and other N-dansylamino acids were not separated in the present separation system.

Anions such as nitrite, nitrate, iodide, and thiocyanate ions contained in human saliva have been determined by ion chromatography using a microcolumn coated with micellar bile acid derivative, 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate, where only a phosphate buffer solution was used as the mobile phase. The detection limits obtained by the present system were 1.1 μM for nitrite and nitrate, 2.3 μM for thiocyanate, and 0.48 μM for iodide when the direct UV absorption detection of the anions was performed at 230 nm. The present system was applied to the determination of inorganic anions in human saliva, especially in relation with smoking habit, age and sex. Thiocyanate ion was detected at the significantly higher level in saliva for the smokers, compared to the non-smokers. Furthermore, the thiocyanate levels in saliva depended on the age and sex, while the concentrations of nitrite, nitrate, and iodide ions were rather independent of these parameters.

Ultrasonic absorption coefficients in the frequency range from 6.5 to 220 MHz have been measured in aqueous solutions of 3-ethoxy- and 3-butoxypropylamine as functions of their concentrations along with the sound velocity at 2.5 MHz and the density. In a 3-ethoxypropylamine solution, only one relaxational absorption has been observed up to 3.0 mol dm−3. The cause has been clarified to be due to a proton-transfer reaction of the amine from the concentration dependences of the relaxation frequency and the relaxational amplitude. The rate and thermodynamic parameters have been determined and reasonable values have been obtained as a diffusion-controlled reaction. In the solution of 3-butoxypropylamine, another relaxation process in addition to that due to the proton-transfer reaction has been observed in the concentrations of more than 0.5 mol dm−3. This relaxation process has been attributed to a perturbation associated with an aggregation reaction, 4A↔A4, from the concentration dependences of the relaxatio...

Concentration of trace metals forming complexes with large organic molecules in natural waters have been determined. Natural water samples (sea water and lake water) were filtered through a membrane filter (pore size: 0.45 μm) just after sampling, and concentrated by ultrafiltration. The concentrated natural water samples were fractionated by high performance gel filtration chromatography, and metal ion concentration in each fraction was determined by inductively coupled plasma atomic emission spectrometry and/or by graphite furnace atomic absorption spectrometry. Concentration of zinc forming large molecular complexes (LMC) in sea water was 0.07 ngmL−1, and that in lake water was 0.06 ngmL−1. Copper, iron, vanadium, and molybdenum forming LMC in natural waters were also determined. The present results suggest the existences of LMC-forming metal ions, some of which may be metalloenzymes dissolved in natural waters.

Flow injection analysis with spectrophotometric detection has been developed for the determination of phosphorus in biological samples. Potassium peroxodisulfate was used as an oxidizing reagent with aid of a platinum wire as the catalyst, and organophosphorous compounds were converted to orthophosphate which reacted with ammonium molybdate in the presence of ascorbic acid to form the molybdenum blue complex. The absorbance of the complex was detected at 880 nm.