BUNSEKI KAGAKU Abstracts

Vol. 54 No. 11

November, 2005

Research Papers

Synergistic Extraction of Lanthanoids(III) with β-Diketone and Schiff Bases Complexed with Copper(II)

Shuhei Saitou¹, Satoshi Kumaki¹ and Yuko Hasegawa¹

(Received 26 May 2005, Accepted 8 September 2005)

When lanthanoids(III) were extracted with Htta (2-thenoyltrifluoroacetone) and H₂(saltn) (N,N'-disalicylidenetrimethylenediamine), a small synergistic effect was observed. The degree of the effects decreased along with the lanthanoid atomic number: Pr^III>Eu^III>Yb^III. When Cu(saltn) was employed instead of H₂(saltn), the extraction was remarkably enhanced. The enhancement was equivalent to that with Htta and topo, which is well-known as a strong Lewis base. The sequence of the lanthanoids giving a large synergistic effect was similar to that with H₂(saltn). The result suggests that the reason why Cu(saltn) and Htta give large synergistic extraction for Ln^III is due to the formation of binuclear complexes.

Keywords : synergistic extraction; lanthanoids(III); Schiff bases; Cu(saltn); binuclear complexes.

Determination of Tellurium in Coal Samples by Means of Graphite Furnace Atomic Absorption Spectrometry after Coprecipitation with Iron(III) Hydroxide

Sachi Oda¹ and Yoshiko Arikawa¹

(Received 28 April 2005, Accepted 17 September 2005)

A simple and accurate method for the determination of tellurium in coal samples was investigated by the combustion of samples under a high pressure of oxygen and coprecipitation with Fe(OH)₃, followed by a measurement by graphite furnace atomic absorption spectrometry (GF-AAS). About 0.5 g of an accurately weighed ground coal sample and 0.5 g of starch were combusted in an oxygen combustion bomb filled with oxygen to 3 Mpa and added with 3 ml of water as a absorbing solution. The formed tellurium trioxide TeO₃ dissolved in water as TeO₄^2-, which was in turn reduced to TeO₃^2- by heating. After diluting the above-mentioned solution up to about 50 ml with water, Fe(OH)₃ is formed upon adding Fe(NO₃)₃ and sodium hydroxide solutions at pH 8~9 and left standing overnight. After dissolving the precipitate by HCl, the solution was diluted to 10 ml with water and the concentration of tellurium was measured by GF-AAS at a wavelength of 214.3 nm. The standard addition method was employed for the determination of tellurium in real coal samples, because those processes for the formation of tellurium(VI) oxide and coprecipitation with Fe(OH)₃ were interfered by matrices. For NIST SRM 1632c, the standard coal sample tellurium content of 0.057±0.004 mg kg^-1 was in good agreement with the information value of 0.05 mg kg^-1 with 7% of RSD in five replicate analyses. The tellurium contents in 20 real coal samples given by Center for Coal Utilization, Japan were also determined. The tellurium contents in these samples were scattered over the narrow range between 0.032 and 0.100 mg kg^-1.

Keywords : tellurium; coal; GF-AAS; coprecipitation; oxygen combustion.

Technical Papers

Determination of Trace Amounts of Elements in High-Purity Iron Steels and Cr-Fe Alloy by ICP-OES after Anion-Exchange Separation

Fuyuki Sakamoto¹, Kunio Takada¹ and Kazuaki Wagatsuma¹

(Received 15 April 2005, Accepted 5 September 2005)

A method for the determination of a µg g^-1 levels of 8 elements in high-purity iron, low-alloy steels, Cr-Fe alloy, and tool steels has been developed. In matrix separation, iron and chromium in the sample solution were passed through a strongly basic anion-exchange resin column with 2 M HF solution. The 8 elements adsorbed on resin, such as Hf, Mo, Nb, Sn, Ta, Ti, W, Zr, were eluted by a nitric acid -hydroperoxide solution and determined by ICP-OES simultaneously. This method could be employed for the analysis of tool steel containing large amount of molybdenum.

Keywords : ICP-OES; anion-exchange; high-purity iron; tool steel; molybdenum; tungsten.

Reviews

Highly Sensitive Detection Methods in Microchip Electrophoresis

Fumihiko Kitagawa¹ and Koji Otsuka¹

(Received 29 June 2005, Accepted 27 July 2005)

Microchip electrophoresis (MCE) can achieve faster analysis with small sample volumes. However, the concentration sensitivity is generally insufficient due to the small sample mass injected and the detection volume. To improve the detection sensitivity limitations of MCE, several detection schemes for high sensitivity and/or high performance have been introduced. In the early stage of developing MCE, laser-induced fluorescence (LIF) spectrometry was mainly employed as a detection scheme. Recently, other detection methods, e.g., UV absorption, electrochemical detection, conductometry, mass spectrometry and so forth, have been introduced in MCE. In the present article, the principles and features of the detection schemes applied to MCE are presented and the advantages of these methods are reviewed based on recent papers.

Keywords : microchip electrophoresis; laser-induced fluorescence spectrometry; electrochemical detection; mass spectrometry.

Accounts

Design of in situ Solid-Phase Extraction for a Simple and Rapid Preconcentration of Trace Chemical Species for Field Work and Its Application to the Speciation of Environmental Water Samples

Minoru Okumura¹, Kaoru Fujinaga¹ and Yasushi Seike¹

(Received 10 May 2005, Accepted 15 July 2005)

In situ solid-phase extraction, which is a simple and rapid in situ method using a small column (Sep-Pak cartridge) for the preconcentration of trace chemical species in environmental water samples for field work, has been developed for applications to the speciation of chemical species in aqueous environments. In this method, water samples are taken into a graduated syringe to prevent them from contacting with air and from contamination, and to perform all operations of the solid-phase extraction procedure easily without any instrument in field work. A hydrophobic Sep-Pak C₁₈ cartridge was used to collect chemical species, such as H₂S, NH₃, Fe(II), and Mn(II); an oxine-loaded Sep-Pak cartridge was used for heavy metals, such as Cd, Co, Cu, Ni, Pb, and Zn; a connected cartridge, consisting of two cartridges (Sep-Pak C₁₈ and TBAHS-loaded Sep-Pak) was used for SO₃^2- and S₂O₃^2-; a zirconium-loaded Sep-Pak cartridge was used for PO₄^3- and As(III, V); and a OH-anion exchange Sep-Pak cartridge was used for sulfide of lake sediment and dissolved CO₂. Through sample collection by Sep-Pak cartridges as a small column, it is advantageous and more convenient to make the sample size smaller for the sake of easy carriage and long storage of samples in field work. As results of applying in situ solid-phase extraction to environmental water, the speciation of some redox-sensitive chemical species, such as Mn(II), H₂S and Fe(II), and As(III, V), in brackish lakes was shown.

Keywords : solid-phase extraction; preconcentration; speciation; environmental water; Sep-Pak cartridge.

Research Papers

Determination of Dimethylsulfide and Dimethyldisulfide in Foods by Thermal Desorption GC/MS

Hiroaki Mastuura¹, Katsuji Fujiyama¹ and Yoshihiro Ikeuchi¹

(Received 17 December 2004, Accepted 8 August 2005)

A thermal desorption-GC/MS was used for the determination of dimethylsulfide (DMS) and dimethyldisulfide (DMDS), characteristic odor components in various foods. These volatile components in food were vaporized by bubbling nitrogen gas, and were collected into a porous polymer beads-type tube, Tenax-TA, placed at the outlet of the flow. The tube was then transferred into a thermal-desorption apparatus and GC/MS analysis was performed. The bubbling time and the flow rate of nitrogen gas were examined to optimize the extracting condition. In the thermal desorption-GC/MS method, most of the vaporized compounds were collected in the adsorbent tube, and injected all at once, while only a part of the vaporized compounds was injected in by the headspace method, generally used for flavor analyses. The calibration curve showed good linearity in the range of 0.5~500 ng ml^-1. The recovery of the compounds varried from 60 to 106%, depending on the type of samples. The detection limit of this method was 0.1 ng g^-1 sample, and the reproducibility was 4.1~6.8% (R.S.D.). In this study, using the thermal desorption method, it was reconfirmed that the heating process affects the measurement value of the concentration of DMS and DMDS in several dairy products and vegetable extracts. This report also presents new findings concerning the quantities of DMS and DMDS in several fermented foods, seafood, and coffee products.

Keywords : thermal desorption-GC/MS; dimethylsulfide (DMS); dimethyldisulfide (DMDS); food samples.

Rapid and Convenient Discrimination of Various Types of Fats and Oils by Proton Nuclear Magnetic Resonance Spectroscopy

Shoji Kurata¹, Kazutaka Yamaguchi¹, Saki Ohtsuka² and Masatoshi Nagai²

(Received 15 June 2005, Accepted 29 August 2005)

A convenient analytical method for the rapid discrimination of various types of fats and oils was developed using a 500 MHz proton nuclear magnetic resonance spectroscopy (¹H-NMR). One hundred scans were recorded for 11 types of 10% (v/v) fats and oils (six vegetable oils and five animal oils) in deuterated chloroform using tetramethylsilane as an internal standard without sample preparation, such as the saponification. The ¹H-NMR analysis rapidly and simultaneously detected both triacylglycerols and sterols in the fats and oils. All of the fats and oils were discriminated by the degree of unsaturation of fatty acids composing triacylglycerols, the types of fatty acids and sterols, and the integrated intensity ratios of sterols to the triacylglycerols obtained in the ¹H-NMR spectra.

Keywords : proton nuclear magnetic resonance spectroscopy (¹H-NMR); fats and oils; discrimination; fatty acid; sterol.

Technical Papers

Forensic Discrimination of Unsaponifiables of Fats and Oils Using Gas Chromatography/Mass Spectrometry

Kazutaka Yamaguchi¹ and Shoji Kurata¹

(Received 20 June 2005, Accepted 18 August 2005)

Fifty-one types of fats and oils were analyzed using gas chromatography/mass spectrometry (GC/MS) of unsaponifiables for developing their forensic discrimination in this study. This method could distinguish vegetable oils and animal fats by the discrimination of sterols. The analytical results showed that sesamin and sesamolin, capsaicine and dyhidrocapsaicine, and spinasterol were characteristic unsaponified compounds useful for the identification of sesame oil, mustard seed oil, and camellia oil, respectively. All 32 types of vegetable oils could be discriminated by comparing of unsaponifiables. Higher alcohols from saponified wax were also useful for the discrimination of fats and oils; 19 types of animal fats were classified into 13 groups only by the analysis of unsaponifiables, because the types of unsaponifiables of animal fats were much fewer than those of vegetable oils. Accordingly, the GC/MS analysis of unsaponifiables in this study was very useful for the discrimination of fats and oils.

Keywords : fats and oils; GC/MS; discrimination; sterol; unsaponifiable.

Determination of Trace Uranium in Epoxy Resin for Semiconductor Devices by Fluorescence Spectrometry after Anion Exchange Separation and Thenoyltrifluoroacetone Liquid-Liquid Extraction

Hiroshi Mitsumata¹ and Yoshiyuki Kita¹

(Received 30 May 2005, Accepted 1 September 2005)

We have established a method for ppb levels of uranium in epoxy resins. This method involves the following procedure: 1) After 10 g of sample is decomposed at 800°C, hydrofluoric acid and hydrochloric acid decomposition is achieved. 2) Sodium carbonate and potassium carbonate are added to the residue, followed by fusion. 3)The sample solution(in 8 N HCl) for anion exchange is passed through the column with packed the Muromac1-X8, so that uranium is adsorbed on the Muromac. Uranium is eluted with 0.5 N hydrochloric acid. The collected effluent is used to prepare a sample solution for thenoyltrifluoroacetone (TTA) extraction. 4) After adjusting the pH of the sample solution to approximately 7, 0.2 M TTA/benzene extraction is achieved. The organic layer is stripped, and then the aqueous layer is heated to dryness. 5) The mixed flux (sodium fluoride+sodium carbonate+potassium carbonate) is added, followed by fusion. By using an obtained cake sample, the quantity of uranium is assayed by fluorescence spectrometry. Research has clarified that this method can assay ppb levels of uranium in epoxy resin for semiconductor devices.

Keywords : fluorescence spectrometry; anion exchange; thenoyltrifluoroacetone liquid-liquid extraction; TTA; epoxy resin for semiconductor device; uranium.

Determination of Cd, Cr and Pb in Polyethylene Resin by Inductively Coupled Plasma Atomic Emission Spectrometry after Open System Wet Decomposition Using a Mixture of Nitric Acid and Sulfuric Acid

Hideaki Minami¹, Shigenori Nishiuchi¹, Jun'ichirou Kadono¹ and Taketoshi Nakahara²

(Received 22 April 2005, Accepted 2 September 2005)

A new sample-preparation method was proposed for the determination of cadmium (Cd), chromium (Cr) and lead (Pb) in polyethylene resin by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The polyethylene resin sample was decomposed by using a mixture of nitric acid and sulfuric acid. The bumping was reduced by using a new type of watch glass with a stem. The precipitation of PbSO₄ was dissolved by an aqueous solution of 20~25% ammonium acetate/acetic acid. The standard reference materials of resin (BCR-680, BCR-681) were analyzed to verify the proposed method. The obtained results for Cd, Cr and Pb by this method were in good agreement with their certified and reference values.

Keywords : cadmium; chromium; lead; inductively coupled plasma atomic emission spectrometry; resin; BCR680; BCR681; watch glass; WEEE; RoHS.

Digests of Doctoral Dissertation

Development of Gas-Phase Sample Introduction Techniques for the Determination of Trace Elements by Analytical Atomic Spectrometry

Akihiro Matsumoto

Wakayama Industrial Technology Center, 60, Ogura, Wakayama-shi, Wakayama, 649-6261

(Awarded by Osaka Prefecture University dated September 30, 2004)

A new sensitive analytical atomic spectrometry coupled with gas-phase sample introduction methods was investigated. First, the single and multi-element determination methods for As, Sb, Bi, Se, Te, Sn and Pb by high power nitrogen microwave induced plasma (N₂-MIP), as a new excitation source for atomic emission spectrometry (AES), an annular-shaped high power N₂-MIP produced at atmospheric pressure by an Okamoto cavity, which coupled with hydride generation have been investigated. Second, a trace amount of carbon was determined by atmospheric-pressure helium (He)-MIP-AES with the generation of carbon dioxide. Finally, inductively coupled plasma (ICP)-AES and quartz tube atomization atomic absorption spectrometry (QTA-AAS) couple with a gas-phase sample introduction technique for the determination of copper, cadmium and silver were investigated. As a result, when compared with conventional solution nebulization, a great improvement in the sensitivity was attained in each instance. After the effects of several diverse elements, trace elements were determined by the proposed methods: As, Sb, Bi, Se, Te, Sn, Pb, Cu and Ag in steels, C in aqueous solutions and Cd in polyethylene. The results obtained by this method were in good agreement with their certified values.

(Received July 1, 2005)

Keywords : gas-phase sample introduction method; high power nitrogen microwave induced plasma; atomic emission spectrometry; hydride generation method; steels; aqueous solutions; polyethylene.

Applications of Monte-Carlo Simulation to Electron Probe Microanalyzer Analysis

Yoshio Osada

Osada Techno Labo, 2416-6, Ooka, Numazu-shi, Shizuoka 410-0022

(Awarded by Kyoto University dated May 23, 2005)

In order to apply the Monte-Carlo simulation method (MC) to Electron Probe Microanalyzer (EPMA) analysis, it is very important to establish an appropriate x-ray attenuation model. Here, the x-ray attenuation model was assumed to be a rectangular parallelepiped. In the case of small particles, the lengths X, Y, Z of the rectangular parallelepiped were varied from 1 to 10 µm (bulk), respectively. In the case of bulk samples, the lengths X, Y, Z of the rectangular parallelepiped were used as X=Y=Z=10 µm. In the case of thin films, the lengths X, Y, Z of the rectangular paral1el piped were used as X=Y=10 µm and Z=100~500 nm. Using this x-ray attenuation model, we developed the MC program for the personal computers (PC). This program can trace electron trajectories and calculate the characteristic x-ray intensities following absorption. After that, using this developed program we studied: (1)the relation between the incident electron number and the relative error, (2)the discrimination between α-AlFeSi and β-AlFeSi, Al₆Fe and Al₃Fe in an aluminum matrix, (3)the thickness determination of natural aluminum oxide films and (4)the quantitative analysis method of samples coated with evaporated layers.

(Received July 19, 2005)

Keywords : Monte-Carlo simulation; EPMA; mapping; oxide film; non-conducting sample.

Go to the page of "Bunseki Kagaku"

Go to the top page of JSAC

©2005 The Japan Society for Analytical Chemistry
All rights reserved.
26-2, Nishigotanda 1-chome, Shinagawa-ku, Tokyo 141-0031, JAPAN