BUNSEKI KAGAKU, Abstracts

Vol. 4 9, No. 4

April, 2000


Review

Soil analyses by ICP-MS (Review)

Shin-ichi Yamasaki*

*Laboratory of Soil Science, Faculty of Agricultural, Tohoku University, 1-1, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555

(Received 22 November 1999)

Soil analyses by inductively coupled plasma mass spectrometry (ICP-MS) are reviewed. The first half of the paper is devoted to the development of techniques applicable to soil analyses, where diverse analytical parameters are carefully evaluated. However, the choice of soil samples is somewhat arbitrary, and only a limited number of samples (mostly reference materials) are examined. In the second half, efforts are mostly concentrated on the introduction of reports, where a large number of samples and/or very precious samples have been analyzed. Although the analytical techniques used in these reports are not necessarily novel, valuable information concerning such topics as background levels of elements in soils, chemical forms of elements in soils and behavior of elements in soil ecosystems and the environment can be obtained. The major topics discussed are total elemental analysis, analysis of radionuclides with long half-lives, speciation, leaching techniques, and isotope ratio measurements.

Keywords : inductively coupled plasma mass spectrometry (ICP-MS); total analysis; radionuclides; speciation; leaching techniques; isotope ratio measurement.


Research Papers

Study of appropriate sampling intervals of digital data in chromatography

Chikako Yomota, Yoko Tagashira*, Mari Katsumine, Kazuo Iwaki**, Rieko Matsuda and Yuzuru Hayashi***

*Osaka Branch, National Institute of Health Sciences, 1-1-43, Hoenzaka, Chuo-ku, Osaka 540-0006
**Center for Technology Development, Ebara Research Co. Ltd., 4-2-1, Honfujisawa, Fujisawa-shi, Kanagawa 251-8502
***National Institute of Health Sciences, 1-18-1, Kami-Yoga, Setagaya-ku, Tokyo 158-8501

(Received 8 October 1999, Accepted 24 January 2000)

An A/D converter is used to transform the analog output of a detector into digital data. This paper examines the influences of the sampling intervals of the detection system on the relative standard deviation (RSD) of measurements. Two chromatographic systems (HPLC and IC) were taken. The measurement RSD is provided by the FUMI theory, without replication. If the sampling intervals are too long, the RSD is unnecessarily large because of poor peak recognition. Excessively short intervals cannot improve the precision greatly. As a rule of thumb, we show that 30-50 data points over the signal domain of a peak are appropriate for obtaining the reasonable precision from the digital data.

Keywords : chromatography; precision; sampling intervals of data.


Study of some digital processing methods for appropriate sampling intervals of digital data in chromatography

Rieko Matsuda, Yuzuru Hayashi*, Chikako Yomota, Yoko Tagashira**, Mari Katsumine, and Kazuo Iwaki***

*National Institute of Health Sciences, 1-18-1, Kami-Yoga, Setagaya-ku, Tokyo 158-8501
**Osaka Branch, National Institute of Health Sciences, 1-1-43, Hoenzaka, Chuo-ku, Osaka 540-0006
***Center for Technology Development, Ebara Research Co. Ltd., 4-2-1, Honfujisawa, Fujisawa-shi, Kanagawa 251-8502

(Received 8 October 1999, Accepted 24 January 2000)

Various kinds of digital processing methods are used for obtaining the highest possible amount of information from digital data. This paper treats the effects of some digital processings (boxcar, trimming, moving average method and exponential smoothing) on the precision (RSD) of measurements. The following rules of thumb concerning an A/D converter, multi-channel detector and smoothing are obtained: 1) The data collection time of an A/D converter should be set at a large value near or equal to the sampling intervals of the A/D converter; 2) The smaller is the number of frequencies detected in the multi-channel detector, the higher is the precision of measurements; 3) The smoothing (moving average method and exponential smoothing) is effective for height measurement, and not for area measurement. The original data should be stored for another analysis.

Keywords : chromatography; precision; sampling intervals of data.


Technical Papers

Determination of trace antimony(III) in water by graphite-furnace AAS after preconcentration with 4-(2-pyridylazo)resorcinol and Capriquat loaded silica gel

Hiroki Tange, Masayoshi Yasuda and Takashi Goto*

*Department of Industrial Chemistry, College of Engineering, Nihon University, 1, Nakagawara, Tokusada, Tamura, Koriyama-shi, Fukushima 963-8642

(Received 22 November 1999, Accepted 8 January 2000)

The separation and preconcentration of trace Sb(III) from water for a graphite- furnace AAS (GF-AAS) determination was studied using silica gel loaded with 4-(2-pyridylazo)resorcinol (PAR)/trioctylmethylammonium chloride (Capriquat). A sample solution of 100~2000 ml containing Sb(III) was adjusted to pH 2.5. The solution was then passed through a column packed with 0.5 g of PAR/Capriquat-loaded in silica gel on the column, eluted with 10 ml of 0.8 M hydrochloric acid, and then deteminated by GF-AAS. In this method, over 98% of the Sb(III) was adsorbed at about pH 2.5. Ascorbic acid was used as a masking reagent to remove any interference of Fe(III). The proposed method has been applied to the determination of Sb(III) in seawater and spring-water samples.

Keywords : antimony(III); PAR/Capriquat loaded silica gel; GF-AAS; seawater.


Determination of uranium in water samples by ICP-AES with chelating resin disk preconcentration

Tsutomu Miura, Takao Morimoto, Kazuhiko Hayano and Takeshi Kishimoto*

*Japan Chemical Analysis Center, 295-3, Sanno-cho, Inage-Ku, Chiba 263-0002

(Received 8 November 1999, Accepted 17 January 2000)

An analytical method of uranium in water samples by ICP-AES using a 3M EmporeTM chelating resin disk for solid-phase extraction has been developed. A trace amount of uranium was quantitatively collected with an EmporeTM chelating resin disk (47 mmφ) at a flow rate of 100~150 ml min-1 from a sample solution (pH 5.0) under the presence of 100 mM CH3COONH4 and 1 mM DCTA. The interference elements (Fe, Th, etc) were separated at the same time during the preconcentration of uranium. Uranium was then quantitatively eluted with 7.5 ml of 2 M HNO3. A preconcentration factor of 200-fold was achieved with a 2.0 l sample. The present method has been applied to the determination of uranium in seawater and mineral-water samples. The analytical results of uranium were almost in good agreement with literature values and the results of other methods (ICP-MS and α-ray spectrometry). The concentrations of uranium in mineral-water samples were from <0.1 to 1.7 µg l-1.

Keywords : uranium; ICP-AES; chelating resin disk preconcentration; seawater; mineral-water.

Characterization by TOF-SIMS of the interface between a lubricant film and a carbon film on a thin-film magnetic recording disk

Tetsuo Amemiya, Nobuyuki Yoshino, Yoshio Umeda* and Yoshimasa Nihei**

*Shibukawa Plant, Denki Kagaku Kogyo K. K., 1135, Nakamura, Shibukawa-shi, Gunma 377-0002
**Institute of Industrial Science, University of Tokyo, 7-22-1, Roppongi, Minato-ku, Tokyo 106-0032

(Received 10 May 1999, Accepted 3 February 2000)

The structure of the interface between a lubricant film and a carbon film on a thin film magnetic recording disk was investigated by TOF-SIMS. Fombiln AM2001, Fomblin Z. DOL and Fomblin Z. DIAC of perfluoropolyether were used for a lubricant, and the sputtering carbon film A was used for a carbon film. It was considered by TOF-SIMS that the terminal groups of Fomblin AM2001 interacted with sp2 elements of a carbon film, the terminal groups of Fomblin Z. DOL, Fomblin Z. DIAC combined with water elements of a carbon film through hydrophilic combination. The results showed that the lubricant which combined with a carbon film were "Bonded lubricant", the other which not combined with a carbon film were "Free lubricant".

Keywords : thin film magnetic recording disk; TOF-SIMS; lubricant of perfluoropolyether; bonded lubricant; free lubricant.


Notes

Screening method for serum γ-globulin concentration using a sulfosalicylic acid solution containing Triton X-100 as a precipitant

Yuji Suzuki*

*Saitama Prefectural University Junior College, 820, Sannomiya, Koshigaya, Saitama 343-8540

(Received 28 October 1999, Accepted 29 January 2000)

The reaction of a 30 g/l sulfosalicylic acid solution containing Triton X-100 with serum protein has been investigated. The result indicated that this reagent has an ability for protein fractionation, and was thought to precipitate the serum γ-globulin in the concentration region of about more than 70 g/l Triton X-100. The measurement values obtained by this reagent containing 70 g/l Triton X-100 correlated well with the serum γ-globulin concentrations by the conventional method combining the biuret method and cellulose acetate electrophoresis (r=0.917). It seems that this reagent can be used for screening the serum γ-globulin concentration.

Keywords : screening method; serum γ-globulin; sulfosalicylic acid; Triton X-100.


Spectrophotometric determination of nitrate and nitrite in natural water samples based on an oxime formation reaction of phenol

Yasuhiro Gou*

*The Kumamotoshi Eastern Purification Center, 536, Akita, Akitsumachi, Kumamoto 861-2105

(Received 14 October 1999, Accepted 7 February 2000)

The spectrophotometric method for the determination of nitrate reported by Velghe and Clays was modified. The modified method was applied to the determination of nitrate and nitrite in natural water samples (well, river, and seawater). In the modified method, a sodium chloride solution was used instead of hydrohloric acid as the source of chloride for reducing nitrate. The sensitivity of this method was comparable to that of ion chromatography and that of HPLC with UV detection. The results obtained by the proposed method were in good agreement with those obtained by the chromatographic methods. The proposed method could be applied to the determination of nitrate of low concentration levels in seawater sample.

Keywords : nitrate; nitrite; phenol; spectrophotometry; seawater.


Technical Letters

Identification of fatty acid composing metal salt of it in resins by alcohol added thermal extraction with high-frequency heating

Kenji Kurihara and Fumiyo Tanoue

Analysis Center, Dainippon Ink & Chemicals, Inc., 631, Sakado, Sakura-shi, Chiba 285-8668

(Received 8 September 1999, Accepted 12 January 2000)

Keywords : thermal extraction; polymer; high-frequency heating; fatty acid metal salts; GC/MS.


Identification of polyester resin components by alcohol added thermal extraction with high-frequency heating

Kenji Kurihara and Fumiyo Tanoue*

*Analysis Center, Dainippon Ink & Chemicals, Inc., 631, Sakado, Sakura-shi, Chiba 285-8668

(Received 8 September 1999, Accepted 12 January 2000)

Keywords : thermal extraction; polyester; GC/MS; high-frequency heating; esterification.


Digest of Doctoral Dissertation

Studies on improving the sensitivity and performance in inductively coupled plasma atomic emission spectrometry

Yoshisuke Nakamura

National Research Institute for Metals, 1-2-1, Sengen, Tsukuba-shi, Ibaraki 305-0047

(Awarded by Chuo University dated March 28, 1998)

In order to improve the sensitivity of ICP-AES, the plasma torch was rearranged from a radially viewed to an axially viewed type. By using a long torch instead of a conventional torch, that is likely to be influenced by the atmosphere, S/N was significantly improved. This was because blocking the atmosphere caused the disappearance of the molecular spectrum of NO and NH, and a decrease of the noise as well as an increase of the observed quantity of light due to extension of plasma. The use of an ultrasonic nebulizer and the long torch caused a high transport efficiency and a desolvation effect. Furthermore, it improved S/B and S/N to a great extent because of the characteristics of the long torch. When measured by electrothermal vaporization, an emission intensity-time-wavelength measurement and time resolution combined, the precision of the time-resolved signal was remarkably improved without a time-resolved signal. Furthermore, to achieve a higher performance of ICP-AES, the direct determination of a trace amount of rare-earth elements (REEs) in REE by ICP-AES using a high-resolution echell spectrometer and metal solid samples by spark ablation/ICP-AES were investigated. In the former case, the spectral interferences between REEs including matrices were eliminated by means of a data-treatment method. In the later, it was necessary to optimize the total Ar gas flow rate in order to obtain a large inclination of the calibration curve. The results obtained in this study will be useful to develop a new analytical technique for ICP-AES.

(Received November 26, 1999)

Keywords : axially viewed of horizontal ICP-AES; improvement of sensitivity with a long torch; echell spectrometer with wavelength modulation; time resolution; electrothermal vaporization; spark ablation.


Chemical modification of silica-based packing materials for high-performance liquid chromatography

Yoshihisa Sudo

Kurume Laboratory, Chemicals Evaluation and Research Institute, Japan
19-14, Chuomachi, Kurume-shi, Fukuoka 830-0023

(Awarded by Tokyo Metropolitan University dated July 15, 1999)

Silica gel is the most widely used as a packing material for HPLC. It possesses the advantages of high mechanical strength, a large number of theoretical plates, ease of chemical modification of the surface and availability at a relatively low price. The demand for further improvements in the performance of silica-based packing materials has been increasing. In this study, improvements of reversed-phase packing materials, restricted access media (RAM) and chiral stationary phases were achieved through the development of new methods for silica surface modification. An end-capping method using high-temperature silylation was developed, which produced octadecylsilylated silica gel (ODS) without and undesirable effects of residual silanol groups. In a study on RAM, glycerylalkylsilylated silica gels with alkyl moiety ranging from C3 to C6 were prepared as a new type of RAM. These packing materials did not adsorb proteins, but could retain small molecules, such as drugs, in direct injection analysis of serum samples. This is one of the simplest methods for preparing RAM. In the addition, a low-temperature plasma treatment was applied to the preparation of RAM. The plasma more easily removed octadecyl groups on the external surface of ODS to produce silanol groups than those on the internal surface. The silanol groups were glycerylpropylsilylated to produce RAM. Furthermore, some novel chiral stationary phases were prepared by covalently bonding chiral binaphthol and its derivatives to silica gels. These stationary phases showed enantioselectivity mainly for basic compounds. The hydroxyl groups of binaphthol played a dominant role in chiral recognition and retention.

(Received February 1, 2000)

Keywords : HPLC; packing material; silica gel; ODS; end-capping; restricted access media; chiral stationary phase; binaphthol.


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