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山本, 敦 ; 早川, 和一 ; Yamamoto, Atsushi ; Hayakawa, Kazuichi
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金沢大学理工研究域自然システム学系
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山本, 敦 ; 松永, 明信 ; 関口, 久義 ; 早川, 和一 ; 宮崎, 元一
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Photometric ion chromatography is a novel method by using the photometer as a detector. A feature of this method is the use of light absorbing ion in the mobil phase, and the appearance of transparent sample ion in the effluent is
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detected by "trough"in the base line absorbance. We applied this technique by using a conventional HPLC system equipped with a commercially available ion exchange separation column to the determination of bromate in such foodstuffs as bread and kamaboko. Sample solution was prepared by aqueous extraction and mixed with acetone for removal of proteins. After evaporation of the organic solvent, the aqueous solution was dechlorinated by a DOWEX column (Ag-form), and then was subjected to chromatography. Samples of bread and kamaboko were spiked with 5.4 ppm and 8.4 ppm of bromate, respectively, and examined by the above method. The average recoveries were 88.3% in bread and 82.9% in kamaboko, and the coefficients of variation were 7.7% and 7.9%, respectively. The detection limit was 1 ppm. The above findings indicate that bromate can be detected by HPLC using conventional instrumentation, and the sensitivity of this system is comparable to conductimetric detection.
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早川, 和一 ; 山本, 敦 ; 宮崎, 元一
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Ion chromatography (IC), which was introduced in 1975, has become widely used for the sensitive and simultaneous determination of ions. In the early stage, the IC system consisted of two ion-exchange columns (separator and suppressor,
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respectively) and a conductivity detector. Although this combination is still the most popular, new forms of separation and suppression have been developed. On the other hand, an indirect photometric detection using a UV detector has become popular in IC and other detectors commonly used in HPLC also have been used. Each of them has specific advantages for different types of analyses. Thus, IC is now defined as a form of liquid chromatography of ions. This article reviews new developments of the different forms of IC and their applications, especially to environmental samples, foods, biological materials and drugs, from reports published since 1990.
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松永, 明信 ; 山本, 敦 ; 水上, 英一 ; 早川, 和一 ; 宮崎, 元一
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A high-performance liquid chromatographic method using post column reaction system was established for the determination
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of polyphosphates (PP). Linear polyphosphates with the range of polymerization from 2 to 9 (P2-P9) could be separated on an anion exchange column, TSK GEL DEAE-5PW (Toyo Soda), with 0.01 M HNO3 containing NaNO3 as a mobile phase at flow rate of 1.0 ml/min, with a linear gradient in NaNO3 concentration at one hour intervals. PP were detected as the decrease of absorbance at 500 nm of ferric-sulfosalicylate complex by means of an on-line post column reaction at room temperature, with 0.5 mM FeCl3 containing 2.5 mM sulfosalicylic acid as reaction reagent at flow rate of 0.5 ml/min. The proposed method was applied to the analysis of 30 different commercial products of soft drinks. The pretreatment only necessary after mixing the sample with an equal volume of 0.01 M HNO3 was filtration through 0.45 μm pore size filter. P2-P6 (total 0.231 g/kg) and P2-P4 (0.070 g/kg) were found from 2 kinds of the samples, respectively. The determination limit was 0.02 m mol/kg for all of the PP.
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山本, 敦 ; 松永, 明信 ; 牧野, 正雄 ; 早川, 和一 ; 宮崎, 元一
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A method for the simultaneous determination of organic acids was investigated by photometric ion chromatography by using
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two different eluents. A 4.6 mm i.d.×25 cm stainless column packed with MCI GEL SCA 01 (Mitsubishi Chemical Ind., Ltd.) was used as a separator column. Sample was injected into this column previously equilibrated with 1 mM citraconic acid at pH 6.8. After elution of monobasic organic acids, the eluent was exchanged to a stronger one, 1 mM m-sulfobenzoic acid at pH 6.8. Dibasic organic acids were eluted before the column reequilibration with the secondary eluent. On the other hand, tribasic organic acids such as citric acid were eluted with the secondary eluent. To prevent the base line disorder due to the eluent exchange, the determination at 254 nm was performed. Because this wave length is an isosbestic point of the two eluents. Sour-taste agents in soft drinks could be analysed directly after dilution of samples.
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伊藤, 宏 ; 早川, 和一 ; 山本, 敦 ; 村瀬, 篤 ; 星野, 邦広 ; 久野, 稔 ; 早川, 和美
概要:
金沢大学医薬保健研究域薬学系<br />ガスクロマトグラフ(GC)は, 大気, 室内空気をはじめ環境試料中の悪臭, におい分析など幅広い用途で多用される分析装置である.GC装置は, キャピラリーカラムやマススペクトロメトリー検出器の開発に伴
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う分離, 同定能力の向上後は, 成熟した分析装置と見られることが多くなった.しかし, インジェクターのセプタムにシリコンゴムシールが使われている.このため, (1)使用温度に上限がある, (2)セプタムの汚染によるバックグラウンドの上昇や妨害ピークが発生する, (3)加熱脱着, 熱分解分析などに専用の装置を必要とする, などの課題が残されている.これらの課題を解決するため, 従来のキャリヤーガスライン外側にもう一層のガスラインを設け, このガスでキャリヤーガスシールする方法(セプタムフリーインジェクターと呼称する)を検討した.その結果, 複雑なシール機構を必要としたインジェクター部の構造を簡略化でき, 前述の課題を解決できることが分かった. 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.
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早川, 和一 ; 山本, 敦
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金沢大学医薬保健研究域薬学系<br />これまで, 液体クロマトグラフィーにおける吸光度検出器は専ら光吸収を有する化合物を検出する装置であり, その原理と検出器は既に完成されたものとの印象が強かった.本総説は, 上述の概念を大きく変革しつつ
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ある吸光度検出法の新展開として, 光吸収のない対象物質を検出できる間接吸光度検出法と, 更にその考え方を光学活性物質の検出に向けた偏光吸光度検出法に焦点を合わせ, 著者らの研究成果も含めて紹介する. New photometric detection methods developed for use in liquid chromatography have been reviewed. Differential photometric detection using UV-visible absorbing modifiers enabled us to examine the retention and detection mechanism of not only analytes but also mobile phases. Indirect photometric detection ion chromatography based on this theory separately and sensitively determines ionic compounds using a conventional high-performance liquid chromatographic system with a UV-visible absorbance detector. This method is useful for many kinds of samples such as environmental water, foods and biological materials. Polarized photometric detection mathods with two polarizers on either side of a UV-visible absorbance detector flow cell have been developed. The monitor determines optically active compounds as the change in absorbance. This method was effectively applied for determining sugars and organic acids
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