Direct Determination of Inorganic Ions at Sub-ppb Levels by Ion Chromatography Using Water as a Mobile Phase

1995 ◽  
Vol 67 (20) ◽  
pp. 3713-3716 ◽  
Author(s):  
Wenzhi. Hu ◽  
Mamoru. Tominaga ◽  
Hiroaki. Tao ◽  
Akihide. Itoh ◽  
Tomonari. Umemura ◽  
...  
Keyword(s):  
Ion Chromatography ◽  
Mobile Phase ◽  
Direct Determination ◽  
Inorganic Ions

Direct determination of bromide ions in sea water by ion chromatography using water as the mobile phase

1996 ◽  
Vol 322 (1-2) ◽  
pp. 43-47 ◽  
Author(s):  
Hu Wenzhi ◽  
Cao Shun-an ◽  
Mamoru Tominaga ◽  
Akira Miyazaki
Keyword(s):  
Ion Chromatography ◽  
Mobile Phase ◽  
Sea Water ◽  
Direct Determination ◽  
Bromide Ions

Selectivity coefficients of some simple and complex inorganic ions for Spheron DEAE

1984 ◽  
Vol 49 (10) ◽  
pp. 2349-2354 ◽  
Author(s):  
František Vláčil ◽  
Karel Koňák
Keyword(s):  
Ion Exchange ◽  
Mobile Phase ◽  
Dynamic Method ◽  
Precious Metals ◽  
Inorganic Ions ◽  
Chromatographic Determination ◽  
Chloride Ions ◽  
Chloro Complexes ◽  
Selectivity Coefficients

The selectivity coefficients of the nitrate and chloride ions and of anionic chloro complexes of Au(III), Rh(III), Pd(II), and Pt(IV) for ion exchange on Spheron DEAE in the chloride form are determined by the dynamic method. the complex anion species formed are identified and the ion exchange nature of the sorption of precious metals on this sorbent is confirmed based on the elution order of the precious metals as determined previously by the column chromatography on Spheron DEAE using hydrochloric acid as the mobile phase. The effect of the presence of perchlorate in the mobile phase during the liquid chromatography of precious metals and during the chromatographic determination of nitrate traces is explained.

scholarly journals Direct Determination of Free Methionine in Soy-Based Infant Formula

2004 ◽  
Vol 87 (1) ◽  
pp. 123-128
Author(s):  
Paul Johns ◽  
Rosalyn Phillips ◽  
Lobat Dowlat
Keyword(s):  
Infant Formula ◽  
Mobile Phase ◽  
Method Comparison ◽  
Water System ◽  
Direct Determination ◽  
Reversed Phase ◽  
Intermediate Precision ◽  
Relative Standard ◽  
Limit Of Quantitation

Abstract A method was developed for the direct determination of free methionine in soy-based infant formula, with analyte separation and quantitation by reversed-phase liquid chromatography (LC), and UV absorbance at 214 nm, respectively. Sample preparation required only dilution with mobile phase and syringe filtration. Using a 0.02M KH 2 PO 4 mobile phase (pH adjusted to 2.9 with 85% o-phosphoric acid) and 0.7 mL/min flow rate, methionine eluted at approximately 8 min, and total run time was 14 min after column regeneration with acetonitrile–water. System linearity was demonstrated as peak area versus analyte concentration, ranging from 80 to 120% of the formula specification for free methionine (r > 0.999, and all residuals <0.45%). Intermediate precision relative standard deviation values were <1.5% for ready-to-feed and reconstituted powder samples, and recoveries ranged from 98.0 to 103.5% for inter-method comparison with an amino acid analyzer method. The limit of quantitation was 3 mg methionine/L in the “as fed” infant formula. Despite the relatively weak UV absorptivity of methionine, the 214 nm signal was sufficiently intense in the 30–65 mg/L (201–436 μM) range to afford quantitation by peak area proportionation versus a 2-point external standard calibration. This direct UV detection after reversed-phase LC separation provides a simple and accurate method for determining free methionine without derivatization.

scholarly journals Derivatization Ion Chromatography for the Determination of Monoethanolamine in Presence of Hydrazine in PHWR Steam-Water Circuits

2011 ◽  
Vol 2011 ◽  
pp. 1-5
Author(s):  
Ayushi D. ◽  
Arijit Sengupta ◽  
Sangita D. Kumar ◽  
A. G. Kumbhar ◽  
G. Venkateswaran
Keyword(s):  
Ion Chromatography ◽  
Mobile Phase ◽  
Limit Of Detection ◽  
Accurate Method ◽  
Feed Water ◽  
Relative Standard ◽  
Conductometric Detection ◽  
Mode A ◽  
Eluent Acetone

A simple, rapid and accurate method for the determination of monoethanolamine (MEA) in PHWR steam-water circuits has been developed. MEA is added in the feed water to provide protection against corrosion while hydrazine is added to scavenge dissolved oxygen. The quantitative determination of MEA in presence of hydrazine was accomplished using derivatization ion chromatography with conductometric detection in nonsuppressed mode. A Metrosep cation 1-2 analytical column and a Metrosep cartridge were used for cation separation. A mixture of 4 mM tartaric acid, 20% acetone and 0.05 mM HNO3was used as eluent. Acetone in the mobile phase leads to the formation of different derivatives with MEA and hydrazine. The interferences due Na+and NH4 +were eliminated by adopting a simple pretreatment procedure employing OnGuard-H cartridge. The limit of detection limit of MEA was 0.1 μg mL−1and the relative standard deviation was 2% for the overall method. The recovery of MEA added was in the range 95%–102%. The method was applied to the determination of MEA in steam generator water samples.

Simultaneous Determination of Floctafenine and its Hydrolytic Degradation Product Floctafenic Acid Using Micellar Liquid Chromatography with Applications to Tablets and Human Plasma

2013 ◽  
Vol 96 (6) ◽  
pp. 1315-1324 ◽  
Author(s):  
Mohamed I Walash ◽  
Fathalla Belal ◽  
Nahed El-Enany ◽  
Manal Eid ◽  
Rania N El-Shaheny
Keyword(s):  
Liquid Chromatography ◽  
Human Plasma ◽  
Degradation Product ◽  
Mobile Phase ◽  
Sodium Dodecyl ◽  
Hydrolytic Degradation ◽  
Direct Determination ◽  
Micellar Liquid Chromatography ◽  
Main Metabolite

Abstract A stability-indicating micellar liquid chromatography (MLC) method was developed and validated for the assay of floctafenine (FLF) in the presence of its degradation product and main metabolite, floctafenic acid (FLA). The analysis was carried out on a CLC Shim-Pack octyl silane (C8) column (150 × 4.6 mm id, 5 μm particle size) using a micellar mobile phase consisting of 0.15 M sodium dodecyl sulfate, 10% n-propanol, and 0.3% triethylamine in 0.02 M orthophosphoric acid (pH = 3). The mobile phase was pumped at a flow rate of 1.0 mL/min with UV detection at 360 nm. The method showed good linearity for FLF and FLA over the concentration ranges of 0.5–25.0 and 0.4–10.0 μg/mL, with LODs of 0.16 and 0.12 μg/mL, respectively. The developed method was successfully applied to the determination of FLF in commercial dispersible tablets, with mean recovery of 98.87 ± 1.37%. Also, the proposed method was specific for the analysis of FLF in presence of the co-formulated drug thiocolchicoside in laboratory-prepared tablets, with mean recovery of 100.50 ± 1.07%. Statistical comparison of the results obtained by the proposed MLC method with those obtained by a comparison method showed good agreement. Moreover, the method was extended to study the degradation behavior of FLF under different International Conference on Harmonization recommended conditions such as alkaline, acidic, oxidative, thermal, and photolytic. The method was further applied for direct determination of FLA as the main metabolite of FLF in human plasma without prior extraction steps, with mean recovery of 110.50 ± 6.5%.

Determination of atmospheric alkylamines by ion chromatography using 18-crown-6 as mobile phase additive

2018 ◽  
Vol 1563 ◽  
pp. 154-161 ◽  
Author(s):  
Shengqian Zhou ◽  
Jing Lin ◽  
Xiaofei Qin ◽  
Ying Chen ◽  
Congrui Deng
Keyword(s):  
Ion Chromatography ◽  
Mobile Phase ◽  
Mobile Phase Additive

Direct determination of phosphate in raw Jatropha curcas oil by ion chromatography

2013 ◽  
Vol 44 ◽  
pp. 459-464 ◽  
Author(s):  
Yi Zhang ◽  
Prapisala Thepsithar ◽  
Xia Jiang ◽  
Joo Hwa Tay
Keyword(s):  
Ion Chromatography ◽  
Jatropha Curcas ◽  
Direct Determination ◽  
Jatropha Curcas Oil
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