Taitō-ku, Japan
Taitō-ku, Japan

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Nakashima Y.,Metrohm Japan Ltd. | Nakashima Y.,Chubu University | Inoue Y.,Nippon Oil Corporation | Yamamoto T.,Chubu University | And 4 more authors.
Analytical Sciences | Year: 2012

A simple and sensitive suppressed ion chromatography (IC) method with conductivity detection for the determination of molybdate in environmental water is proposed. Molybdate in highly saline water was extracted and precocentrated. Preconcentration was accomplished by using a chelating resin using a chelating resin immobilized with carboxymethylated polyethylenimine (Presep® PolyChelate). This resin is able to trap a variety of metal elements without any interference of alkali and alkaline-earth metals. A 30-mL volume of brackish water was adjusted for appropriate pH and then flushed through 100 mg of the chelating resin. Molybdate concentrated on the resin could be easily eluted with 6 mL of 0.1 M NaOH. A large volume injection method for IC was achieved with in-line neutralization of the effluent. The determination of 0.6 μg L-1 molybdate in highly saline water was made possible with a 500-μL injection. Samples of brackish water were taken at various distances from the river mouth. The determined concenctrations of molybdate correlated closely with concentrations of chloride. © 2012 The Japan Society for Analytical Chemistry.


Nakashima Y.,Metrohm Japan Ltd. | Suzuki S.,Metrohm Japan Ltd. | Yamazaki M.,Metrohm Japan Ltd. | Inoue Y.,Nippon Oil Corporation | And 2 more authors.
Bunseki Kagaku | Year: 2010

A determination method of nitrate and nitrite in foodstuffs using ion chromatography (IC) equipped with an inline dialysis system is presented. The conditions of the inline dialysis system were optimized for the simultaneous extraction of nitrate and nitrite. Under the optimized conditions, the detection limits (S/N =3) for nitrate and nitrite when injecting 20 μL with UV detection were 0.08 mg L-1 and 0.05 mg L-1, respectively. The linear range of both ions was over 3 orders of magnitude, from 0.1 mg L-1 to 20 mg L-1. The relative standard deviation (RSD, n =10) for nitrate and nitrite in sausage was 2.43% and 1.57%, respectively. The inline dialysis system combined with IC was applied to the simultaneous determination of nitrate and nitrite in foodstuffs, such as ham and sausage, and was compared to the determined values obtained by a solid-phase extraction-IC method and an enzyme-reduction spectrometric method. Good correlations for both ions between the inline-dialysis-IC method and the enzyme reduction spectrometric method were obtained. However, the results of the solid-phase extraction-IC method and the inline-dialysis-IC method did not show a good correlation, because the matrices could not be removed very well, and interfered with measurements in the solid extraction - IC method. The present method will be useful for the determination of inorganic ions in food samples containing high-concentration matrixes. © 2010 The Japan Society for Analytical Chemistry.


Nakashima Y.,Metrohm Japan Ltd | Nakashima Y.,Chubu University | Yamazaki M.,Metrohm Japan Ltd | Suzuki S.,Metrohm Japan Ltd | And 4 more authors.
Bunseki Kagaku | Year: 2013

The applicability of metal oxide as a selective extractant for ionic compounds was investigated to establish an easy and selective determination method using ion chromatography coupled with conductivity detection. The extraction properties of zirconia and titania for glyphosate (N-(phosphonomethyl)glycine, GLYP) as an analyte were evaluated. Although it has been recognized that both zirconia and titania have high affinity for phosphate compounds, the leakage of GLYP from a solid-phase extraction cartridge packed with the titania used in this study was observed. On the other hand, zirconia could perform an effective extraction of GLYP with high retention ability. Also, a solid-phase extraction cartridge packed with 35 mg of the zirconia was able to certainly entrap GLYP in spite of a sample load of 250 mL. GLYP entrapped on the zirconia could be eluted with 2 mL of 0.4 M sodium hydroxide as an eluent. GLYP in the effluent could be sensitively detected by ion chromatography with conductometric detection using neutralization employing a suppressor module. The proposed method was applied to the determination of GLYP in urban river water samples. The limit of quantification was around 0.001 mg L-1 for GLYP. © 2013 The Japan Society for Analytical Chemistry.


Nakashima Y.,Metrohm Japan Ltd. | Suzuki S.,Metrohm Japan Ltd. | Yamazaki M.,Metrohm Japan Ltd. | Inoue Y.,Nippon Filcon Co.Ltd. | And 2 more authors.
Analytical Sciences | Year: 2011

A quantitative analysis was developed for eight acidic and neutral preservatives in foods and daily necessities using the inline dialysis-IC combined with hydrophobic anion-exchange separation. The eight preservatives were dialyzed by inline dialysis and separated on a hydrophobic anion exchange column. Under the optimized separation conditions, the detection limits (S/N = 3) for the eight preservatives were from 0.08 to 0.66 mg L-1, moreover, a good linearity (R2 > 0.998) for each preservative was obtained in the range to 100 mg L-1. Although the dialysis rate of the neutral preservatives was not so high, a good repeatability (RSD, n = 8) of less than 1.5% for the eight preservatives was obtained. The inline dialysis-IC method was applied to the determination of the preservatives in foods and daily necessities. The preservatives were quantified without any interference. The proposed method will be useful for the determination of the preservatives in foods and daily necessities containing high concentration matrices. © 2011 The Japan Society for Analytical Chemistry.


Yamazaki M.,Metrohm Japan Ltd | Yamamoto T.,Metrohm Japan Ltd | Kobayashi Y.,Metrohm Japan Ltd | Nakashima Y.,Metrohm Japan Ltd
Bunseki Kagaku | Year: 2014

The metal elimination device which used a traditional cation-exchange type suppressor was combined with a suppressed-IC to determine trace anions automatically in metal content samples. First, the removal efficiency of metal ions with the metal elimination device was evaluated, and then a reproduction process of the cation exchanger was established. Next, this inline metal elimination-IC system was evaluated concerning its precision and reproducibility. The system could successfully quantify ppb levels of anions in sample solutions including 400 ppm of copper ion. Finally, the system was applied to the determination of trace chloride in metal salt reagents and a soft etching solution. As a result, a fixed quantity of the chloride ion less than 1 mg kg-1 was possible. © 2014 The Japan Society for Analytical Chemistry.


PubMed | Metrohm Japan Ltd.
Type: Evaluation Studies | Journal: Analytical sciences : the international journal of the Japan Society for Analytical Chemistry | Year: 2011

A quantitative analysis was developed for eight acidic and neutral preservatives in foods and daily necessities using the inline dialysis-IC combined with hydrophobic anion-exchange separation. The eight preservatives were dialyzed by inline dialysis and separated on a hydrophobic anion exchange column. Under the optimized separation conditions, the detection limits (S/N = 3) for the eight preservatives were from 0.08 to 0.66 mg L(-1), moreover, a good linearity (R(2) > 0.998) for each preservative was obtained in the range to 100 mg L(-1). Although the dialysis rate of the neutral preservatives was not so high, a good repeatability (RSD, n = 8) of less than 1.5% for the eight preservatives was obtained. The inline dialysis-IC method was applied to the determination of the preservatives in foods and daily necessities. The preservatives were quantified without any interference. The proposed method will be useful for the determination of the preservatives in foods and daily necessities containing high concentration matrices.


PubMed | Metrohm Japan Ltd.
Type: Journal Article | Journal: Analytical sciences : the international journal of the Japan Society for Analytical Chemistry | Year: 2012

A simple and sensitive suppressed ion chromatography (IC) method with conductivity detection for the determination of molybdate in environmental water is proposed. Molybdate in highly saline water was extracted and preconcentrated. Preconcentration was accomplished by using a chelating resin using a chelating resin immobilized with carboxymethylated polyethylenimine (Presep() PolyChelate). This resin is able to trap a variety of metal elements without any interference of alkali and alkaline-earth metals. A 30-mL volume of brackish water was adjusted for appropriate pH and then flushed through 100 mg of the chelating resin. Molybdate concentrated on the resin could be easily eluted with 6 mL of 0.1 M NaOH. A large volume injection method for IC was achieved with in-line neutralization of the effluent. The determination of 0.6 g L(-1) molybdate in highly saline water was made possible with a 500-L injection. Samples of brackish water were taken at various distances from the river mouth. The determined concentrations of molybdate correlated closely with concentrations of chloride.

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