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論文
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Hayakawa, Kazuichi ; Kato, Akio ; Yamamoto, Atsushi ; Miyazaki, Motoichi
概要:
In non-suppressed conductometric ion chromatography, when a carboxylic acid eluent of low pH is used, the signal intensi
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ty (ΔHc) is proportional to the sum of the conductivity change caused by changes in the sample concentration (ΔCs) as well as conductivity changes caused by changes in the eluent concentration (ΔCe). This can be expressed as ΔHC=B(ΔCs)+B(ΔCe), where B is a constant. In this equation, ΔCs is constant for any sample species. However, ΔCe varies with changes in the sample capacity factors. This value is positive when the sample elutes before the system peak (k′s<k′e), and is negative when it elutes after the system peak (k′s>k′e). Therefore, the sample peak intensity (ΔHC) is enhanced prior to the system peak and is suppressed after it. These effects increase the closer the sample and the system peaks. The effect of this theory was proved by a determination of orthophosphate using a TSK gel IC-Anion-PW column and a 0.75mM phthalic acid eluent. The detection limit of this method for orthophosphate (1×10-11mol, with an S/N of three) was smaller (by a factor of 10-30) than those by previous conventional ion chromatographic methods. Also, the interference of chloride or nitrate, often observed in the previous methods, was removed by suppressing their peak intensities. When this method was applied for the determination of orthophosphate in environmental samples, other interfering compounds were effectively removed by a column-switching system attached to the ion chromatograph, and a trace level of the orthophosphate was determined.
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| 2.
論文 |
論文
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早川, 和一 ; 平木, 博美 ; 宮崎, 元一
概要:
金沢大学医薬保健研究域薬学系<br />入手が容易なイオン交換カラムを備えた普及型HPLC装置で可能な,無機陰イオンの微量分析条件を検討した.無機陰イオン(炭酸イオン,塩化物イオン,亜硝酸イオン,リン酸イオン,臭化物イオン,硝酸イオン,硫酸
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イオン,ヨウ化物イオン)は,フタル酸二ナトリウム溶液を溶離液として,陰イオン交換カラムで分離溶出された後,ベースラインの谷として紫外検出される.炭酸イオン,塩化物イオン,リン酸イオン,臭化物イオン,硝酸イオン,硫酸イオンの同時分析の最適条件は,カラム:Zipax SAX (2.1 mm i.d.×50cm):溶離液:5×10^<-4> Mフクル酸二ナトリウム;流速:1 ml/min; 温度:室温;検出波長:240 nm;注入量:100μlであった.この条件で,検出下限はppbレベルであり,ピーク高さ法と面積法のいずれでも検量線は直線となった.本法を用いると,環境試料中の主要無機陰イオンが短時間に一斉分析でき,しかも本法の分析値は,他法の結果ともよく一致した. A photometric determination method of microamounts of inorganic anions has been developed by conventional high performance liquid chromatography using a popular ion exchange column. Inorganic anions (HCO_3^-, Cl^-, NO_2^-, H_2PO_4^-, Br^-, NO_3^-, SO_4^<2->, and I^-) were separated on an anoin exchange column by using disodium phthalate solution as an eluent, and detected as troughs in the base line absorbance by a UV monitor. The optimum conditions for the determination of HCO_3^-, C1^-, H_2PO_4^-, Br^-, NO_3^-, and SO_4^<2-> were as follows : column, Zipax SAX (2.1 mm i.d. ×50cm) ; eluent, 5×10^<-4>M disodium phthalate ; flow rate, 1 ml/min ; column temperature, ambient ; detection wavelength, 240 nm. Under the conditions described above, detection limits of these anions were at levels as low as ppb. The calibration curves gave straight lines by either peak height or peak area method. Main inorganic anions contained in environmental samples could be simultaneously determined by the proposed method, and their analytical results were close to those obtained by other methods.
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