BUNSEKI KAGAKU Abstracts

Vol. 54 No. 3

March, 2005

Accounts

Developement of a Simple ion Chromatography Using Chemical Reactions and Application to Environmental Analysis

Makoto Nonomura¹

(Received 9 August 2004, Accepted 1 November 2004)

This paper describes a simple ion chromatography (IC) using a conductometric detector (CD) for undetectable species, and insoluble gas components. The ion species that can't be measured with CD are changed to detectable ion species by chemical reactions, and insoluble gas components are collected in an alkanolamine absorbing solution. The cyanide ion (CN^-, pK_a=9.2) and metal cyanide complexes were changed to cyanate ion (CNO^-, pK_a=3.66) by sodium hypochlorite or a chloramine T solution, after which they were determined by IC with CD. Residual chlorine (Cl₂, pK_a=7.5) was changed to CNO^- by a p-toluenesulfonamide and potassium cyanide (KCN) solution, and could be determined by IC with CD. In addition, it was proved that the residual chlorine changed to CNO^- by a KCN solution, directly. The methods were applied to the determination of cyanide compounds in a plating solution and wastewater, and residual chlorine in tap water. We found that nitrogen dioxide (NO₂) was collected in a triethanolamine (TEA) absorbing solution, and nitrogen monoxide (NO) was oxidized to NO₂ by ultraviolet irradiation, after which they were determined by IC. The acid components, such as sulfur oxides, hydrogen chloride and nitrogen oxides, were collected in a TEA absorbing solution, and determined by IC, simultaneously. Carbon dioxide was collected in a 2-amino-2-methyl-1-propanol absorbing solution, and could be determined by IC using a KOH eluent and CD. Formaldehyde in water was oxidised to formic acid by hydrogen peroxide (H₂O₂) and a KOH solution, and could be easily determined by IC. In addition, low sulfur (<10 ppm) in fuel was determined by IC after combusion to sulfur oxides, and collected in a H₂O₂ absorbing solution.

Keywords : ion chromatogaphy; conductometric detection; cyanide compounds; residual chlorine; nitrogen oxides; carbon dioxide; formaldehyde.

Research Papers

Dew Point Measurement of High Purity Gas with Slab Optical Waveguide Technique

Naoko Uchida¹, Akiko Takatsu¹ and Kenji Kato¹

(Received 13 September 2004, Accepted 19 November 2004)

A remarkable feature of the slab optical waveguide (SOWG) technique is internal multi-reflection in a thin core layer. It allows one to detect only samples on the surface of SOWG with high sensitivity. This technique has so far been applied to the detection of various samples, such as dye molecules and proteins. As a new application field, an experimental dew-point measurement system based on the SOWG technique was tested for moisture analysis in high-purity nitrogen (N₂) gas. The system consisted of both cooling and light-detection components. The former had a Peltier thermoelectric temperature controller and a platinum resistance probe to cool the SOWG, as do conventional chilled mirror hygrometers. The latter had a light source, optical fibers, a photo detector, and a slide glass-shaped quartz plate as the SOWG to detect light signals. While wet N₂ gas with a certain water concentration (approximately -60°C at the dew point) was introduced into the system, the analytical capability of the system was evaluated under various conditions, such as different sample gas flow rates, cooling speeds, thicknesses of the SOWG, and introduction times for wet N₂ gas. Since the evaluation provided satisfactory results, the system 1) was available for dew-point detection down to -65°C, 2) had higher sensitivity by utilizing a thinner SOWG, such as 0.1 µm thick, and 3) had a fast response time, compared with a conventional capacitance-type hygrometer. The SOWG technique was concluded to apply to trace moisture measurements in high-purity gas.

Keywords : slab optical waveguide spectroscopy; dew point; moisture; gas; hygrometer.

Study on Mass Spectral Database Obtained by Liquid Chromatography/Mass Spectrometry for Retrieval System of Chemicals

Michiko Uebori¹, Yoshiaki Ishii², Atsuko Hasegawa³, Yasuko Yoshida⁴, Shigeru Suzuki⁵ and Kiyoshi Imamura¹

(Received 16 September 2004, Accepted 22 November 2004)

Information on the mass spectra obtained by liquid chromatography/mass spectrometry (LC/MS), the relative retention time (RRT), and the distribution coefficient (octanol/water) (log P_ow) was considered in order to construct a mass spectral database of the LC/MS. One hundred and fifty three compounds selected among the specific compounds nominated in the law of Pollutant Release and Transfer Register (PRTR) System were measured by four different types of LC/MS equipment. Four kinds of mass spectra for each compound were obtained by two operation modes (positive and negative) and two ionization types {electro spray ionization (ESI) and atmospheric pressure chemical ionization (APCI)} and were recorded in a mass-spectral database. The mass spectra of the compounds were classified into two categories: positive and negative, because of their similarities in two ionization types. A standard operating condition of LC/MS was proposed to normalize the retention times of obtained compounds, which were normalized in the RRT as an indicator of o-chloroaniline. The RRT and the log P_ow of the compounds were stored in the database as among the items for retrieval.

Keywords : LC/MS; database; relative retention time (RRT); log Pow; standard method.

Technical Papers

Development of Septum-Free Injector for Gas Chromatography

Hiroshi Ito^1,2, Kazuichi Hayakawa², Atsushi Yamamoto³, Atsushi Murase¹, Kunihiro Hoshino⁴, Minoru Kuno⁴ and Kazumi Hayakawa¹

(Received 23 July 2004, Accepted 15 November 2004)

The gas-chromatograph (GC) is a type of analytical equipment that has been most commonly used in environmental studies such as concerning offensive odors and residual pesticides. The GC has been regarded as being a well-developed analytical equipment, since the introduction of a capillary column made high-resolution analysis possible, and hyphenation with a mass-spectrometry detector advanced the identification ability. There are, however, several disadvantages to be improved. For instance, a silicone rubber seal is used in a septum for a sample injector. Therefore, (1) there is an upper limit to the applicable temperature, (2) the background level increases and/or interferences are formed by contamination of the septum, and (3) the GC injector requires an exclusive type of equipment for thermal desorption, pyrolysis analyses and so on. To solve these problems, we introduced another carrier gas line, instead of the septum seal outside of the conventional carrier gas line. When the two gas lines are set at the same pressure, leakage of the carrier gas is likely to be prevented, regardless of the existence of hole for the preparing the syringe needle. We called it a “septum-free injector”. In this paper, we demonstrate the analytical features of this novel injector.

Keywords : gas-chromatography; septum-free injector; sealing gas line; high temperature.

Homogeneous Liquid-Liquid Extraction of Metal-1,10-Phenanthroline Chelates in a Weak Acidic Solution

Hitoshi Yamaguchi¹, Shinji Itoh¹, Shukuro Igarashi² and Takeshi Kobayashi¹

(Received 24 September 2004, Accepted 6 December 2004)

We studied phase separation in a weak acidic solution by homogeneous liquid-liquid extraction. Using acetone as a water-soluble organic solvent, 1,10-phenanthroline as a chelate-forming agent, and Zonyl FSA as a phase-separating agent, we developed a phase-separating method for 14 kinds of elements, such as Al, Cu, and Ti, in a weak acid (around pH 2). With the addition of 1 ml of 50 v/v% Zonyl FSA, the volume of the segregating phase was 100 µl. The recovery rate of each element by this method was 95% or more, demonstrating that various types of chelate-forming agents can be used in homogeneous liquid-liquid extraction in a weak acid and that this method could be applied in a wide range of practical fields.

Keywords : homogeneous liquid-liquid extraction; 1,10-phenanthroline; weak acidic solution; Zonyl FSA; ICP-OES.

Notes

Simple Analysis for Inorganic Anions in Air Samples by Means of Capillary Electrophoresis

Mamiko Mutoh¹, Seiko Yakuwa¹, Eri Hoshino¹, Yukiko Imaizumi¹ and Yoshiko Arikawa¹

(Received 27 July 2004, Accepted 1 November 2004)

Nonmetallic components in the air were determined by capillary electrophoresis as Cl^-, NO₂^-, NO₃^-, SO₄^2-and F^-in condensed water of moisture in the air, collected by a dehumidifier. Indirect absorbance detection of anions was accomplished with a mixed solution of 2 mmol/l ammonium molybdate-1.5 mmol/l diethylenetriamine at pH 8.5 in capillary electrophoresis. More than 5 anions in condensed water were detected at the ppm level without concentration. The sampling time of condensed water necessary for the analysis was several minutes, and the migration time for the separation of 5 anions was within 8 minutes. This method can be applied to monitor nonmetallic components in the air in a flow system.

Keywords : nonmetallic components; air; condensed water; capillary electrophoresis.

Analytical Reports

Results of Proficiency Testing for Determination of Dioxins in Marine Sediment (3^rd round) based on ISO/IEC Guide 43-1

Yo-ichi Ishibashi¹, Shozo Asada¹, Hiroyuki Igaki¹, Shu-ichi Yamada¹, Satoshi Tsuruta¹, Makoto Shimura¹, Kazutoshi Kakita¹, Akihiro Ono¹ and Mamoru Sakata¹

(Received 11 August 2004, Accepted 7 November 2004)

The Japan Society for Analytical Chemistry carried out a third proficiency test for the determination of dioxins (polychlorodibenzo-p-dioxins, polychlorodibenzofurans and coplanar polychlorobiphenyls) in marine sediment. Proficiency testing of analytical laboratories is based on ISO/IEC Guide 43-1, “Proficiency testing by interlaboratory comparisons”. This testing was carried out from May '02 to August '02, with the participation of 104 laboratories. The test results were: 37.05 pg-TEQ/g of total Dioxin concentration on average; 7% in robust coefficient of variation. A total of 9 labs have been estimated to be unsatisfactory due to their large z score in the robust method, over 3 in absolute value.

Keywords : dioxins; marine sediment; proficiency testing; z score.

Digests of Doctoral Dissertation

Preparation of Anion-Imprinted Resin by a Surface-Imprinting Polymerization Method and Its Use for Chemical Separation

Isamu Fujiwara

Center for Waste Water Treatment, Science Research Center, Yamaguchi University, 1677-1, Yoshida, Yamaguchi-shi, Yamaguchi 753-8511

(Awarded by Kyusyu University dated March 25, 2003)

A imprinting polymerization method is useful for the preparation of functional host polymers. Anion-imprinted resins prepared by the “surface imprinting polymerization method (SIPM)”, which builds an imprinted structure on the surface of a particle, were investigated. First, ferrocyanide-imprinted resins were prepared by SIPM with ferrocyanide (template) from an O/W emulsion consisting of oleylamine (functional surfactant) and divinylbenzene (matrix monomer), and were also prepared using quarternary ammonium salts for stabilizing the emulsion. This resin adsorbed ferrocyanide ion more effectively due to the imprinting operation (imprinting effects) than a non-imprinted resin (reference). From the IR spectra of ferrocyanide adsorbed on the resin, the ferrocyanide was adsorbed on a ferrocyanide-imprinted resin surface that had a more hydrophobic environment to compare with the non-imprinted resin. Second, condensed phosphate anion-imprinted resin was prepared by SIPM with oleylamine and oleylalcohol, which is a neutral auxiliary surfactant. Then, a double amount of oleylalcohol against oleylamine was suitable for preparing tripolyphosphate-imprinted resin. Because the tripolyphosphate was less adsorbed on the pyrophosphate- and phosphate-imprinted resin than the tripolyphosphate- and non-imprint resin, the selectivity to the target anion was found. Third, an organic anion-imprinted resin was also investigated. Finally, ferrocyanide-imprinted uniform microspheres (ca. 0.4 mm diameter) were prepared using the pyridinium group by combining seeded emulsion polymerization method and SIPM; they were found to adsorb ferrocyanide ion about 200-times more strongly than non-imprinted ones. Cu(II)-imprinted microspheres as well as anion-imprinted ones were prepared using the imidazole group, and those adsorbed a template more effectively than did the non-imprinted ones.

(Received October 15, 2004)

Keywords : surface imprinting polymerization method; O/W emulsion; microspheres; anion; imprinting effects.

Molecular and Enzymatic Studies of Microbial Hydroxysteroid Dehydrogenases for Clinical Analysis

Shigeru Ueda

Department of Diagnostics Research and Development, Asahi Kasei Pharma Corporation, 632-1, Mifuku, Ohito-cho, Shizuoka-shi, Shizuoka 410-2321

(Awarded by Kyoto Prefectural University dated March 23, 2004)

In clinical diagnostics, 3α-hydroxysteroid dehydrogenases have been used to measure the total bile acids (TBA) in serum. Dual-nucleotide cofactor-specific 3α-HSD from Pseudomonas sp. B-0831, a member of the SDR superfamily, catalyzed the oxidation of the antibiotic fusidic acid efficiently with the lowest K_m value among various 3α-hydroxysteroids. The enzyme showed the utility of cofactor analogues, such as thio-NAD⁺, 3-acetylpyridine adenine dinucleotide (APAD⁺) and nicotinamide hypoxanthine dinucleotide (deamino-NAD⁺), and could catalyze the carbonyl reduction of non-steroid substrates, and thus can be named 3α-HSD/CR. Transient-phase kinetic studies using the fluorescence stopped-flow method were conducted with the 3α-HSD, for the first time as prokaryotic 3α-HSD, to characterize the binding mechanism of the nucleotide cofactor. The binding of the oxidized cofactors, NAD⁺ and NADP⁺, agreed well with a one-step mechanism, while that of a reduced cofactor, NADH, showed a two-step mechanism. These results are different from that of 3α-HSD from rat liver which belongs to the AKR superfamily. A simple kinetic model of a highly sensitive enzymatic cycling assay method for TBA, previously developed by utilizing reversible catalytic function of the 3α-HSD in the presence of different kinds of oxidized and reduced cofactors, thio-NAD⁺ and NADH, was proposed and confirmed by the experimental results.

(Received November 11, 2004)

Keywords : 3α-hydroxysteroid dehydrogenase; Pseudomonas sp. B-0831; total bile acids; nucleotide cofactor; transient-phase kinetics.

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