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Kazuhiko Tanaka - One of the best experts on this subject based on the ideXlab platform.
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the simultaneous determination of silicic boric and carbonic acids in natural water via ion exclusion Chromatography with a charged aerosol detector
Separations, 2016Co-Authors: Yu Otsuka, Nobutake Nakatani, Takuya Takahashi, Daisuke Kozaki, Masanobu Mori, Kazuhiko TanakaAbstract:The simple and simultaneous determination of silicic, boric and carbonic acids was made using Ion-Exclusion Chromatography (IEC) and a Corona™ charged aerosol detector (C-CAD). Silicic and boric acids were separated by the column packed with a weakly acidic cation-exchange resin in H+-form and ultra-pure water eluent, and the detector responses were improved by the addition of acetonitrile to eluent. Under the optimized conditions, the simultaneous determination of weak inorganic acids, except for carbonic acid, was successfully performed. When the conversion column packed with a strong acidic cation-exchange resin in Na+- or K+-form was inserted between the separation column and the detector, weak inorganic acids including carbonic acid could be detected by the C-CAD. The calibration curves were linear in the range of 0.5–10 mg·L−1 as Si for silicic acid (r2 = 0.996), 10–100 mg·L−1 as B for boric acid (r2 = 0.998) and 1.3–21 mg·L−1 as C for carbonic acid (r2 = 0.993). The detection limits based on three times the standard deviation were 0.03 mg·L−1 as Si for silicic acid, 0.40 mg·L−1 as B for boric acid and 0.08 mg·L−1 as C for carbonic acid. This method was applicable to river, hot spring and drinking water.
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Simultaneous Spectrophotometric Determination of Orthophosphate and Silicate Ions in River Water Using Ion-Exclusion Chromatography with an Ascorbate Solution as Both Eluent and Reducing Agent, Followed by Postcolumn Derivatization with Molybdate
Analytical sciences : the international journal of the Japan Society for Analytical Chemistry, 2009Co-Authors: Nobutake Nakatani, Daisuke Kozaki, Masanobu Mori, Kiyoshi Hasebe, Wakako Masuda, Ryozo Goto, Nobukazu Nakagoshi, Kazuhiko TanakaAbstract:Ion-Exclusion Chromatography was examined for the simultaneous spectrophotometric determinations of orthophosphate and silicate ions in river water using an ascorbate solution as both an eluent and a reducing agent, followed by postcolumn derivatization using molybdate. The detector responses for both ions increased with increased ascorbic acid concentration in the eluent, but peak tailing was observed for the orthophosphate ion. This suggests that the amounts of undissociated orthophosphate ions increased with decreased eluent pH, resulting in the penetration of the phosphate to the Donnan’s membrane formed on the resin surface. Using a neutral sodium ascorbate solution as an eluent, the peak shape was improved. With optimized separation and derivatization conditions (eluent, 20 mM sodium ascorbate; color-forming reagent, 10 mM sodium molybdate–60 mM sulfuric acid; flow rates of eluent and color-forming reagent, 0.4 and 0.2 mL min –1 ; coil length, 6 m), the detection limits of orthophosphate and silicate ions were 0.9 and 1.0 mg L –1 , respectively. This method was successfully applied to the determination of orthophosphate and silicate ions in Kurose River water and the quantitative evaluations of the effects of water intake to a reservoir and discharge from a biological sewage treatment plant on the fluxes of these ions in the river.
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Simultaneous spectrophotometric determination of phosphate and silicate ions in river water by using Ion-Exclusion chromatographic separation and post-column derivatization
Analytica chimica acta, 2008Co-Authors: Nobutake Nakatani, Daisuke Kozaki, Masanobu Mori, Kiyoshi Hasebe, Wakako Masuda, Nobukazu Nakagoshi, Kazuhiko TanakaAbstract:Abstract The simultaneous spectrophotometric determination of phosphate and silicate ions in river water was examined by using Ion-Exclusion Chromatography and post-column derivatization. Phosphate and silicate ions were separated by the Ion-Exclusion column packed with a polymethacrylate-based weakly acidic cation-exchange resin in the H + -form (TSKgel Super IC-A/C) by using ultra pure water as an eluent. After the post-column derivatization with molybdate and ascorbic acid, so-called molybdenum-blue, both ions were determined simultaneously by spectrophotometry. The effects of sulfuric acid, sodium molybdate and ascorbic acid concentrations and reaction coil length, which have relation to form the reduced complexes of molybdate and ions, on the detector response for phosphate and silicate ions were investigated. Under the optimized conditions (color-forming reactant, 50 mM sulfuric acid–10 mM sodium molybdate; reducing agent, 50 mM ascorbic acid; reaction coil length, 6 m), the calibration curves of phosphate and silicate ions were linear in the range of 50–2000 μg L −1 as P and 250–10,000 μg L −1 as Si. This method was successfully applied to water quality monitoring of Kurose-river watershed and it suggested that the effluent from a biological sewage treatment plant was significant source of phosphate ion in Kurose-river water.
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vacancy ion exclusion Chromatography of carboxylic acids on a weakly acidic cation exchange resin
Journal of Chromatography A, 2003Co-Authors: Kazuhiko Tanaka, James S Fritz, Paul R. Haddad, Mingyu Ding, Murad I H Helaleh, Hiroshi Taoda, Hayato Takahashi, Wenzhi Hu, Kiyoshi Hasebe, Corrado SarzaniniAbstract:In this preliminary study, a new approach to Ion-Exclusion Chromatography is proposed to overcome the relatively poor conductivity detection response which occurs in Ion-Exclusion Chromatography when acids are added to the eluent in order to improve peak shape. This approach, termed vacancy Ion-Exclusion Chromatography, requires the sample to be used as eluent and a sample of water to be injected onto a weakly acidic cation-exchange column (TSKgel OApak-A). Vacancy peaks for each of the analytes appear at the retention times of these analytes. Highly sensitive conductivity detection is possible and sharp, well-shaped peaks are produced, leading to efficient separations. Retention times were found to be affected by the concentration of the analytes in the eluent, and also by the presence of an organic modifier such as methanol in the eluent. Detection limits for oxalic, formic, acetic, propionic, butyric and valeric acids were 0.1, 0.2, 0.3, 0.3, 0.4 and 0.5 μM, respectively, and linear ranges for some acids extended over two orders of magnitude. Precision values for retention times were 0.21% and for peak areas were <1.90%. The vacancy Ion-Exclusion Chromatography method was found to give detection responses four to 10 times higher than conventional Ion-Exclusion Chromatography using sulfuric acid eluent and two to five times higher than conventional Ion-Exclusion Chromatography using benzoic acid eluent.
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ion exclusion Chromatography with conductimetric detection of aliphatic carboxylic acids on a weakly acidic cation exchange resin by elution with benzoic acid β cyclodextrin
Journal of Chromatography A, 2003Co-Authors: Kazuhiko Tanaka, James S Fritz, Masanobu Mori, Murad I H Helaleh, Hiroshi Taoda, Kiyoshi Hasebe, Mikaru Ikedo, Paul R. HaddadAbstract:In this study, an aqueous solution consisting of benzoic acid with low background conductivity and β-cyclodextrin (β-CD) of hydrophilic nature and the inclusion effect to benzoic acid were used as eluent for the Ion-Exclusion chromatographic separation of aliphatic carboxylic acids with different pKa values and hydrophobicity on a polymethacrylate-based weakly acidic cation-exchange resin in the H+ form. With increasing concentration of β-cyclodextrin in the eluent, the retention times of the carboxylic acids decreased due to the increased hydrophilicity of the polymethacrylate-based cation-exchange resin surface from the adsorption of OH groups of β-cyclodextrin. Moreover, the eluent background conductivity decreased with increasing concentration of β-cyclodextrin in 1 mM benzoic acid, which could result in higher sensitivity for conductimetric detection. The Ion-Exclusion chromatographic separation of carboxylic acids with high resolution and sensitivity was accomplished successfully by elution with a 1 mM benzoic acid–10 mM cyclodextrin solution without chemical suppression.
Kazutoku Ohta - One of the best experts on this subject based on the ideXlab platform.
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ion exclusion chromatographic behavior of aliphatic carboxylic acids and benzenecarboxylic acids on a sulfonated styrene divinylbenzene co polymer resin column with sulfuric acid containing various alcohols as eluent
Journal of Chromatography A, 2003Co-Authors: Kazutoku Ohta, Atsuya Towata, Masayoshi OhashiAbstract:The addition of C1-C7 alcohols (methanol, ethanol, propanol, butanol, heptanol, hexanol and heptanol) to dilute sulfuric acid as eluent in Ion-Exclusion Chromatography using a highly sulfonated styrene-divinylbenzene co-polymer resin (TSKgel SCX) in the H+ form as the stationary phase was carried out for the simultaneous separations of both (a) C1-C7 aliphatic carboxylic acids (formic, acetic, propionic, isobutyric, butyric, isovaleric, valeric, 2-methylvaleric, isocaproic, caproic, 2,2-dimethyl-n-valeric, 2-methylhexanoic, 5-methylhexanoic and heptanoic acids) and (b) benzenecarboxylic acids (pyromellitic, hemimellitic, trimellitic, o-phthalic, m-phthalic, p-phthalic, benzoic and salicylic acids and phenol). Heptanol was the most effective modifier in Ion-Exclusion Chromatography for the improvement of peak shapes and a reduction in retention volumes for higher aliphatic carboxylic acids and benzenecarboxylic acids. Excellent simultaneous separation and relatively highly sensitive conductimetric detection for these C1-C7 aliphatic carboxylic acids were achieved on the TSKgel SCX column (150 x 6 mm I.D.) in 30 min using 0.5 mM sulfuric acid containing 0.025% heptanol as eluent. Excellent simultaneous separation and highly sensitive UV detection at 200 nm for these benzenecarboxylic acids were also achieved on the TSKgel SCX column in 30 min using 5 mM sulfuric acid containing 0.075% heptanol as eluent.
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separation of aliphatic carboxylic acids and benzenecarboxylic acids by ion exclusion Chromatography with various cation exchange resin columns and sulfuric acid as eluent
Journal of Chromatography A, 2003Co-Authors: Kazutoku Ohta, Masayoshi Ohashi, Jiye Jin, Toyohide Takeuchi, Chuzo Fujimoto, Seongho Choi, Jaejeong Ryoo, Kwangpill LeeAbstract:The application of various hydrophilic cation-exchange resins for high-performance liquid Chromatography (sulfonated silica gel: TSKgel SP-2SW, carboxylated silica gel: TSKgel CM-2SW, sulfonated polymethacrylate resin: TSKgel SP-5PW, carboxylated polymethacrylate resins: TSKgel CM-5PW and TSKgel OA-Pak A) as stationary phases in Ion-Exclusion Chromatography for C1-C7 aliphatic carboxylic acids (formic, acetic, propionic, butyric, isovaleric, valeric, isocaproic, caproic, 2-methylhexanoic and heptanoic acids) and benzenecarboxylic acids (pyromellitic, trimellitic, hemimellitic, o-phthalic, m-phthalic, p-phthalic, benzoic, salicylic acids and phenol) was carried out using diluted sulfuric acid as the eluent. Silica-based cation-exchange resins (TSKgel SP-2SW and TSKgel CM-2SW) were very suitable for the Ion-Exclusion chromatographic separation of these benzenecarboxylic acids. Excellent simultaneous separation of these benzenecarboxylic acids was achieved on a TSKgel SP-2SW column (150 x 6 mm I.D.) in 17 min using a 2.5 mM sulfuric acid at pH 2.4 as the eluent. Polymethacrylate-based cation-exchange resins (TSKgel SP-5PW, TSKgel CM-5PW and TSKgel OA-Pak A) acted as advanced stationary phases for the Ion-Exclusion chromatographic separation of these C1-C7 aliphatic carboxylic acids. Excellent simultaneous separation of these C1-C7 acids was achieved on a TSKgel CM-5PW column (150 x 6 mm I.D.) in 32 min using a 0.05 mM sulfuric acid at pH 4.0 as the eluent.
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simultaneous determination of anions and cations by ion exclusion Chromatography cation exchange Chromatography with tartaric acid 18 crown 6 as eluent
Journal of Chromatography A, 1999Co-Authors: Semog Kwon, Kazuhiko Tanaka, Kwangpill Lee, Kazutoku OhtaAbstract:Ion-Exclusion Chromatography–cation-exchange Chromatography was developed for the simultaneous separation of common inorganic anions and cations (Cl−, NO3− and SO42−; Na+, NH4+, K+, Mg2+ and Ca2+) on a weakly acidic cation-exchange column by elution with weak acid. Generally, the resolution among these monovalent cations was only moderate, thereby hindering the determination of these analytes in natural-water samples. Therefore, 18-crown-6 was added to the eluent to improve the resolution. A good separation of these anions and cations on a weakly acidic cation-exchange column was achieved in 30 min by elution with 5 mM tartaric acid/6 mM 18-crown-6/methanol–water (7.5:92.5). The Ion-Exclusion Chromatography–cation-exchange Chromatography method developed here was successfully applied to the separation of major anions and cations in an environmental water sample.
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ion exclusion Chromatography of aliphatic car ylic acids on a cation exchange resin by elution with polyvinyl alcohol
Journal of Chromatography A, 1997Co-Authors: Kazuhiko Tanaka, Kazutoku Ohta, James S FritzAbstract:Ion-Exclusion Chromatography of aliphatic car☐ylic acids of different acidity (pKa) and hydrophobicity was investigated on a polystyrene-divinylbenzene (PS-DVB) based strongly acidic cation-exchange resin in the H+ form and conductivity detection by elution with polyvinyl alcohol (PVA). When water was used as an eluent, the resolution of the car☐ylic acids was very low and the peak accompanied a fronting depending on their hydrophobicities. Therefore, to improve the peak shape and the peak resolution, aqueous eluents containing PVAs (degrees of polymerization, n=500, 1500and2000) with many OH groups were tested for the Ion-Exclusion chromatographic separation of the car☐ylic acids. When aqueous eluents containing PVA were used, the fronting was decreased dramatically by the effect of increased hydrophilicity of the PS-DVB cation-exchange resin surface due to adsorption of OH group in PVA. The high resolution Ion-Exclusion chromatographic separation without the fronting and highly sensitive conductimetric detection of the car☐ylic acids was accomplished successfully by elution with a 0.2% PVA (n=1500)-10% methanol-water.
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ion exclusion Chromatography of ethanolamines on an anion exchange resin by elution with polyols and sugars
Journal of Chromatography A, 1996Co-Authors: Kazuhiko Tanaka, Kazutoku Ohta, James S FritzAbstract:Abstract Ion-Exclusion Chromatography of mono-, di- and triethanolamines of different basicity (pKb) and hydrophobicity was investigated on a polystyrene-divinylbenzene (PS-DVB)-based strongly basic anion-exchange resin in the OH− form. Conductivity detection and UV detection at 200 nm were used. When water was as an eluent, the ethanoamines were separated from strong base (NaOH) but the resolution was low and some peaks were fronted. This is due mainly to adsorption as a side-effect in the Ion-Exclusion Chromatography. To improve the peak shape and the peak resolution, aqueous eluents containing polyols or sugars with 1–8 alcoholic OH groups (methanol, ethylene glycol, glycerol, erythritol, xylitol, fructose, sorbitol and sucrose) were tested for the Ion-Exclusion chromatographic separation of ethanolamines. When aqueous eluents containing polygols or sugars were used, peak fronting was decreased drastically by increasing a number of OH groups in the polyols and sugars. This is due mainly to the increase in the hydrophilicity of the PS-DVB surface by the OH groups. When an aqueous fructose eluent was used, fructose was strongly adsorbed on the resin surface. By this permanent coating method, the Ion-Exclusion chromatographic separation of ethanolamines was accomplished successfully by elution with water with reasonable resolution and highly sensitive UV and conductimetric detection.
James S Fritz - One of the best experts on this subject based on the ideXlab platform.
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vacancy ion exclusion Chromatography of carboxylic acids on a weakly acidic cation exchange resin
Journal of Chromatography A, 2003Co-Authors: Kazuhiko Tanaka, James S Fritz, Paul R. Haddad, Mingyu Ding, Murad I H Helaleh, Hiroshi Taoda, Hayato Takahashi, Wenzhi Hu, Kiyoshi Hasebe, Corrado SarzaniniAbstract:In this preliminary study, a new approach to Ion-Exclusion Chromatography is proposed to overcome the relatively poor conductivity detection response which occurs in Ion-Exclusion Chromatography when acids are added to the eluent in order to improve peak shape. This approach, termed vacancy Ion-Exclusion Chromatography, requires the sample to be used as eluent and a sample of water to be injected onto a weakly acidic cation-exchange column (TSKgel OApak-A). Vacancy peaks for each of the analytes appear at the retention times of these analytes. Highly sensitive conductivity detection is possible and sharp, well-shaped peaks are produced, leading to efficient separations. Retention times were found to be affected by the concentration of the analytes in the eluent, and also by the presence of an organic modifier such as methanol in the eluent. Detection limits for oxalic, formic, acetic, propionic, butyric and valeric acids were 0.1, 0.2, 0.3, 0.3, 0.4 and 0.5 μM, respectively, and linear ranges for some acids extended over two orders of magnitude. Precision values for retention times were 0.21% and for peak areas were <1.90%. The vacancy Ion-Exclusion Chromatography method was found to give detection responses four to 10 times higher than conventional Ion-Exclusion Chromatography using sulfuric acid eluent and two to five times higher than conventional Ion-Exclusion Chromatography using benzoic acid eluent.
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ion exclusion Chromatography with conductimetric detection of aliphatic carboxylic acids on a weakly acidic cation exchange resin by elution with benzoic acid β cyclodextrin
Journal of Chromatography A, 2003Co-Authors: Kazuhiko Tanaka, James S Fritz, Masanobu Mori, Murad I H Helaleh, Hiroshi Taoda, Kiyoshi Hasebe, Mikaru Ikedo, Paul R. HaddadAbstract:In this study, an aqueous solution consisting of benzoic acid with low background conductivity and β-cyclodextrin (β-CD) of hydrophilic nature and the inclusion effect to benzoic acid were used as eluent for the Ion-Exclusion chromatographic separation of aliphatic carboxylic acids with different pKa values and hydrophobicity on a polymethacrylate-based weakly acidic cation-exchange resin in the H+ form. With increasing concentration of β-cyclodextrin in the eluent, the retention times of the carboxylic acids decreased due to the increased hydrophilicity of the polymethacrylate-based cation-exchange resin surface from the adsorption of OH groups of β-cyclodextrin. Moreover, the eluent background conductivity decreased with increasing concentration of β-cyclodextrin in 1 mM benzoic acid, which could result in higher sensitivity for conductimetric detection. The Ion-Exclusion chromatographic separation of carboxylic acids with high resolution and sensitivity was accomplished successfully by elution with a 1 mM benzoic acid–10 mM cyclodextrin solution without chemical suppression.
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ion exclusion Chromatography of aliphatic car ylic acids on a cation exchange resin by elution with polyvinyl alcohol
Journal of Chromatography A, 1997Co-Authors: Kazuhiko Tanaka, Kazutoku Ohta, James S FritzAbstract:Ion-Exclusion Chromatography of aliphatic car☐ylic acids of different acidity (pKa) and hydrophobicity was investigated on a polystyrene-divinylbenzene (PS-DVB) based strongly acidic cation-exchange resin in the H+ form and conductivity detection by elution with polyvinyl alcohol (PVA). When water was used as an eluent, the resolution of the car☐ylic acids was very low and the peak accompanied a fronting depending on their hydrophobicities. Therefore, to improve the peak shape and the peak resolution, aqueous eluents containing PVAs (degrees of polymerization, n=500, 1500and2000) with many OH groups were tested for the Ion-Exclusion chromatographic separation of the car☐ylic acids. When aqueous eluents containing PVA were used, the fronting was decreased dramatically by the effect of increased hydrophilicity of the PS-DVB cation-exchange resin surface due to adsorption of OH group in PVA. The high resolution Ion-Exclusion chromatographic separation without the fronting and highly sensitive conductimetric detection of the car☐ylic acids was accomplished successfully by elution with a 0.2% PVA (n=1500)-10% methanol-water.
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ion exclusion Chromatography of ethanolamines on an anion exchange resin by elution with polyols and sugars
Journal of Chromatography A, 1996Co-Authors: Kazuhiko Tanaka, Kazutoku Ohta, James S FritzAbstract:Abstract Ion-Exclusion Chromatography of mono-, di- and triethanolamines of different basicity (pKb) and hydrophobicity was investigated on a polystyrene-divinylbenzene (PS-DVB)-based strongly basic anion-exchange resin in the OH− form. Conductivity detection and UV detection at 200 nm were used. When water was as an eluent, the ethanoamines were separated from strong base (NaOH) but the resolution was low and some peaks were fronted. This is due mainly to adsorption as a side-effect in the Ion-Exclusion Chromatography. To improve the peak shape and the peak resolution, aqueous eluents containing polyols or sugars with 1–8 alcoholic OH groups (methanol, ethylene glycol, glycerol, erythritol, xylitol, fructose, sorbitol and sucrose) were tested for the Ion-Exclusion chromatographic separation of ethanolamines. When aqueous eluents containing polygols or sugars were used, peak fronting was decreased drastically by increasing a number of OH groups in the polyols and sugars. This is due mainly to the increase in the hydrophilicity of the PS-DVB surface by the OH groups. When an aqueous fructose eluent was used, fructose was strongly adsorbed on the resin surface. By this permanent coating method, the Ion-Exclusion chromatographic separation of ethanolamines was accomplished successfully by elution with water with reasonable resolution and highly sensitive UV and conductimetric detection.
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simultaneous ion exclusion Chromatography cation exchange Chromatography with conductimetric detection of anions and cations in acid rain waters
Journal of Chromatography A, 1994Co-Authors: Kazuhiko Tanaka, Kazutoku Ohta, James S Fritz, Susumu Matsushita, Akiyoshi MiyanagaAbstract:Abstract A simple, selective and sensitive method was investigated for simultaneously determining anions (Cl−, NO3−, SO42−) and cations (Na+, NH4+, K+, Mg2+, Ca2+) in acid rain and related environmental waters in central Japan. The method involves simultaneous Ion-Exclusion-cation-exchange Chromatography with conductimetric detection on a polyacrylate weakly acidic cation-exchange resin column with a weak-acid eluent. With the weak-acid eluent (tartaric acid) both anions and cations were separated simultaneously, based on Ion-Exclusion and cation-exchange mechanism. Owing to the presence of H+ ions in the tartaric acid eluent, the detector response was positive for the anions and negative for the cations. Using a 5 mM tartaric acid-7.5% methanol-water eluent, good simultaneous separation and detection were achieved in about 30 min. The results indicated an ionic balance of about 100% between the anions (including HCO3−) and the cations (including H+).
Paul R. Haddad - One of the best experts on this subject based on the ideXlab platform.
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vacancy ion exclusion Chromatography of carboxylic acids on a weakly acidic cation exchange resin
Journal of Chromatography A, 2003Co-Authors: Kazuhiko Tanaka, James S Fritz, Paul R. Haddad, Mingyu Ding, Murad I H Helaleh, Hiroshi Taoda, Hayato Takahashi, Wenzhi Hu, Kiyoshi Hasebe, Corrado SarzaniniAbstract:In this preliminary study, a new approach to Ion-Exclusion Chromatography is proposed to overcome the relatively poor conductivity detection response which occurs in Ion-Exclusion Chromatography when acids are added to the eluent in order to improve peak shape. This approach, termed vacancy Ion-Exclusion Chromatography, requires the sample to be used as eluent and a sample of water to be injected onto a weakly acidic cation-exchange column (TSKgel OApak-A). Vacancy peaks for each of the analytes appear at the retention times of these analytes. Highly sensitive conductivity detection is possible and sharp, well-shaped peaks are produced, leading to efficient separations. Retention times were found to be affected by the concentration of the analytes in the eluent, and also by the presence of an organic modifier such as methanol in the eluent. Detection limits for oxalic, formic, acetic, propionic, butyric and valeric acids were 0.1, 0.2, 0.3, 0.3, 0.4 and 0.5 μM, respectively, and linear ranges for some acids extended over two orders of magnitude. Precision values for retention times were 0.21% and for peak areas were <1.90%. The vacancy Ion-Exclusion Chromatography method was found to give detection responses four to 10 times higher than conventional Ion-Exclusion Chromatography using sulfuric acid eluent and two to five times higher than conventional Ion-Exclusion Chromatography using benzoic acid eluent.
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ion exclusion Chromatography with conductimetric detection of aliphatic carboxylic acids on a weakly acidic cation exchange resin by elution with benzoic acid β cyclodextrin
Journal of Chromatography A, 2003Co-Authors: Kazuhiko Tanaka, James S Fritz, Masanobu Mori, Murad I H Helaleh, Hiroshi Taoda, Kiyoshi Hasebe, Mikaru Ikedo, Paul R. HaddadAbstract:In this study, an aqueous solution consisting of benzoic acid with low background conductivity and β-cyclodextrin (β-CD) of hydrophilic nature and the inclusion effect to benzoic acid were used as eluent for the Ion-Exclusion chromatographic separation of aliphatic carboxylic acids with different pKa values and hydrophobicity on a polymethacrylate-based weakly acidic cation-exchange resin in the H+ form. With increasing concentration of β-cyclodextrin in the eluent, the retention times of the carboxylic acids decreased due to the increased hydrophilicity of the polymethacrylate-based cation-exchange resin surface from the adsorption of OH groups of β-cyclodextrin. Moreover, the eluent background conductivity decreased with increasing concentration of β-cyclodextrin in 1 mM benzoic acid, which could result in higher sensitivity for conductimetric detection. The Ion-Exclusion chromatographic separation of carboxylic acids with high resolution and sensitivity was accomplished successfully by elution with a 1 mM benzoic acid–10 mM cyclodextrin solution without chemical suppression.
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simultaneous ion exclusion Chromatography and cation exchange Chromatography of anions and cations in environmental water samples on a weakly acidic cation exchange resin by elution with pyridine 2 6 dicarboxylic acid
Analyst, 2001Co-Authors: Mingyu Ding, Kazuhiko Tanaka, Kiyoshi Hasebe, Paul R. HaddadAbstract:A non-suppressed conductivity detection ion chromatographic method using a weakly acidic cation-exchange column (Tosoh TSKgel OApak-A) was developed for the simultaneous separation and determination of common inorganic anions (Cl–, NO3– and SO42-) and cations (Na+, NH4+, K+, Mg2+ and Ca2+). A satisfactory separation of these anions and cations on the weakly acidic cation-exchange column was achieved in 25 min by elution with a mixture of 1.6 mmol L–1 pyridine-2,6-dicarboxylic acid and 8.0 mmol L–1 18-crown-6 at flow rate of 1.0 mL min–1. On this weakly acidic cation-exchange resin, anions were retained by an Ion-Exclusion mechanism and cations by a cation-exchange mechanism. The linear range of the peak area calibration curves for all analytes were up to two orders of magnitude. The detection limits calculated at S/N = 3 ranged from 0.25 to 1.9 µmol L–1 for anions and cations. The Ion-Exclusion Chromatography–cation-exchange Chromatography method developed in this work was successfully applied to the simultaneous determination of major inorganic anions and cations in rainwater, tap water and snow water samples.
Kiyoshi Hasebe - One of the best experts on this subject based on the ideXlab platform.
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Simultaneous Spectrophotometric Determination of Orthophosphate and Silicate Ions in River Water Using Ion-Exclusion Chromatography with an Ascorbate Solution as Both Eluent and Reducing Agent, Followed by Postcolumn Derivatization with Molybdate
Analytical sciences : the international journal of the Japan Society for Analytical Chemistry, 2009Co-Authors: Nobutake Nakatani, Daisuke Kozaki, Masanobu Mori, Kiyoshi Hasebe, Wakako Masuda, Ryozo Goto, Nobukazu Nakagoshi, Kazuhiko TanakaAbstract:Ion-Exclusion Chromatography was examined for the simultaneous spectrophotometric determinations of orthophosphate and silicate ions in river water using an ascorbate solution as both an eluent and a reducing agent, followed by postcolumn derivatization using molybdate. The detector responses for both ions increased with increased ascorbic acid concentration in the eluent, but peak tailing was observed for the orthophosphate ion. This suggests that the amounts of undissociated orthophosphate ions increased with decreased eluent pH, resulting in the penetration of the phosphate to the Donnan’s membrane formed on the resin surface. Using a neutral sodium ascorbate solution as an eluent, the peak shape was improved. With optimized separation and derivatization conditions (eluent, 20 mM sodium ascorbate; color-forming reagent, 10 mM sodium molybdate–60 mM sulfuric acid; flow rates of eluent and color-forming reagent, 0.4 and 0.2 mL min –1 ; coil length, 6 m), the detection limits of orthophosphate and silicate ions were 0.9 and 1.0 mg L –1 , respectively. This method was successfully applied to the determination of orthophosphate and silicate ions in Kurose River water and the quantitative evaluations of the effects of water intake to a reservoir and discharge from a biological sewage treatment plant on the fluxes of these ions in the river.
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Simultaneous spectrophotometric determination of phosphate and silicate ions in river water by using Ion-Exclusion chromatographic separation and post-column derivatization
Analytica chimica acta, 2008Co-Authors: Nobutake Nakatani, Daisuke Kozaki, Masanobu Mori, Kiyoshi Hasebe, Wakako Masuda, Nobukazu Nakagoshi, Kazuhiko TanakaAbstract:Abstract The simultaneous spectrophotometric determination of phosphate and silicate ions in river water was examined by using Ion-Exclusion Chromatography and post-column derivatization. Phosphate and silicate ions were separated by the Ion-Exclusion column packed with a polymethacrylate-based weakly acidic cation-exchange resin in the H + -form (TSKgel Super IC-A/C) by using ultra pure water as an eluent. After the post-column derivatization with molybdate and ascorbic acid, so-called molybdenum-blue, both ions were determined simultaneously by spectrophotometry. The effects of sulfuric acid, sodium molybdate and ascorbic acid concentrations and reaction coil length, which have relation to form the reduced complexes of molybdate and ions, on the detector response for phosphate and silicate ions were investigated. Under the optimized conditions (color-forming reactant, 50 mM sulfuric acid–10 mM sodium molybdate; reducing agent, 50 mM ascorbic acid; reaction coil length, 6 m), the calibration curves of phosphate and silicate ions were linear in the range of 50–2000 μg L −1 as P and 250–10,000 μg L −1 as Si. This method was successfully applied to water quality monitoring of Kurose-river watershed and it suggested that the effluent from a biological sewage treatment plant was significant source of phosphate ion in Kurose-river water.
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vacancy ion exclusion Chromatography of carboxylic acids on a weakly acidic cation exchange resin
Journal of Chromatography A, 2003Co-Authors: Kazuhiko Tanaka, James S Fritz, Paul R. Haddad, Mingyu Ding, Murad I H Helaleh, Hiroshi Taoda, Hayato Takahashi, Wenzhi Hu, Kiyoshi Hasebe, Corrado SarzaniniAbstract:In this preliminary study, a new approach to Ion-Exclusion Chromatography is proposed to overcome the relatively poor conductivity detection response which occurs in Ion-Exclusion Chromatography when acids are added to the eluent in order to improve peak shape. This approach, termed vacancy Ion-Exclusion Chromatography, requires the sample to be used as eluent and a sample of water to be injected onto a weakly acidic cation-exchange column (TSKgel OApak-A). Vacancy peaks for each of the analytes appear at the retention times of these analytes. Highly sensitive conductivity detection is possible and sharp, well-shaped peaks are produced, leading to efficient separations. Retention times were found to be affected by the concentration of the analytes in the eluent, and also by the presence of an organic modifier such as methanol in the eluent. Detection limits for oxalic, formic, acetic, propionic, butyric and valeric acids were 0.1, 0.2, 0.3, 0.3, 0.4 and 0.5 μM, respectively, and linear ranges for some acids extended over two orders of magnitude. Precision values for retention times were 0.21% and for peak areas were <1.90%. The vacancy Ion-Exclusion Chromatography method was found to give detection responses four to 10 times higher than conventional Ion-Exclusion Chromatography using sulfuric acid eluent and two to five times higher than conventional Ion-Exclusion Chromatography using benzoic acid eluent.
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ion exclusion Chromatography with conductimetric detection of aliphatic carboxylic acids on a weakly acidic cation exchange resin by elution with benzoic acid β cyclodextrin
Journal of Chromatography A, 2003Co-Authors: Kazuhiko Tanaka, James S Fritz, Masanobu Mori, Murad I H Helaleh, Hiroshi Taoda, Kiyoshi Hasebe, Mikaru Ikedo, Paul R. HaddadAbstract:In this study, an aqueous solution consisting of benzoic acid with low background conductivity and β-cyclodextrin (β-CD) of hydrophilic nature and the inclusion effect to benzoic acid were used as eluent for the Ion-Exclusion chromatographic separation of aliphatic carboxylic acids with different pKa values and hydrophobicity on a polymethacrylate-based weakly acidic cation-exchange resin in the H+ form. With increasing concentration of β-cyclodextrin in the eluent, the retention times of the carboxylic acids decreased due to the increased hydrophilicity of the polymethacrylate-based cation-exchange resin surface from the adsorption of OH groups of β-cyclodextrin. Moreover, the eluent background conductivity decreased with increasing concentration of β-cyclodextrin in 1 mM benzoic acid, which could result in higher sensitivity for conductimetric detection. The Ion-Exclusion chromatographic separation of carboxylic acids with high resolution and sensitivity was accomplished successfully by elution with a 1 mM benzoic acid–10 mM cyclodextrin solution without chemical suppression.
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simultaneous ion exclusion Chromatography and cation exchange Chromatography of anions and cations in environmental water samples on a weakly acidic cation exchange resin by elution with pyridine 2 6 dicarboxylic acid
Analyst, 2001Co-Authors: Mingyu Ding, Kazuhiko Tanaka, Kiyoshi Hasebe, Paul R. HaddadAbstract:A non-suppressed conductivity detection ion chromatographic method using a weakly acidic cation-exchange column (Tosoh TSKgel OApak-A) was developed for the simultaneous separation and determination of common inorganic anions (Cl–, NO3– and SO42-) and cations (Na+, NH4+, K+, Mg2+ and Ca2+). A satisfactory separation of these anions and cations on the weakly acidic cation-exchange column was achieved in 25 min by elution with a mixture of 1.6 mmol L–1 pyridine-2,6-dicarboxylic acid and 8.0 mmol L–1 18-crown-6 at flow rate of 1.0 mL min–1. On this weakly acidic cation-exchange resin, anions were retained by an Ion-Exclusion mechanism and cations by a cation-exchange mechanism. The linear range of the peak area calibration curves for all analytes were up to two orders of magnitude. The detection limits calculated at S/N = 3 ranged from 0.25 to 1.9 µmol L–1 for anions and cations. The Ion-Exclusion Chromatography–cation-exchange Chromatography method developed in this work was successfully applied to the simultaneous determination of major inorganic anions and cations in rainwater, tap water and snow water samples.
