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Kolkata, India

Subramanian N.H.,Metrohm India Ltd. | Hariganesh M.R.,Metrohm India Ltd. | Jeevan R.G.,CSIR - Central Leather Research Institute
Journal of Chromatographic Science | Year: 2011

This paper describes a rapid method to determine arsenite assay and arsenate impurity in Arsenic Trioxide Injection using a single conductivity detector. The arsenite assay was determined in a nonsuppressed conductivity detection mode and arsenate impurity was quantified in a suppressed conductivity detection mode. Dualconductivity detections were enabled by valve switching and time programming. The method was validated with respect to specificity, linearity, precision, accuracy, stability, and limit of quantification. The limit of detection and quantification for arsenite were 0.855 mg/L and 2.593 mg/L, and 0.044 mg/L and 0.133 mg/L for arsenate, respectively. Source

Chakraborty J.,Indian Central Glass and Ceramic Research Institute | Sengupta S.,Indian Central Glass and Ceramic Research Institute | Dasgupta S.,National Institute of Technology Rourkela | Chakraborty M.,Indian Central Glass and Ceramic Research Institute | And 4 more authors.
Journal of Industrial and Engineering Chemistry | Year: 2012

The presence of trace level (<1ppm) carbonate ion in the interlayer space of MgAl-LDH has been estimated by ion chromatography technique using a novel inverse chemical suppression method using 0.5mM H 2SO 4 as mobile phase and 25mM LiCl as regenerating solution. The presence of carbonate ion in the LDH structure was found to affect the anion exchange capacity of MgAl-LDH. This has been illustrated by carrying out anion exchange of nitrate ion in the MgAl-LDH structure with chloride ion. The importance of this simple but accurate technique for the carbonate ion estimation is demonstrated and reported in this communication. © 2012 The Korean Society of Industrial and Engineering Chemistry. Source

Annadhasan M.,University of Madras | Muthukumarasamyvel T.,University of Madras | Sankar Babu V.R.,University of Madras | Sankar Babu V.R.,Metrohm India Ltd. | Rajendiran N.,University of Madras
ACS Sustainable Chemistry and Engineering | Year: 2014

In this study, we report a simple and green method for the synthesis of l-tyrosine-stabilized silver (AgNPs) and gold nanoparticles (AuNPs) in aqueous medium under ambient sunlight irradiation. The nanoparticles (NPs) are characterized by UV-visible spectroscopy, high-resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), cyclic voltammetry (CV), and dynamic light scattering (DLS) techniques. The size and shape of the metal NPs could be controlled by changing the concentration of the substrate, metal precursors, and pH of the medium. The synthesized AgNPs are found to be highly sensitive to Hg2+ and Mn2+ ions with the detection limit for both ions as low as 16 nM under optimized conditions. However AuNPs are found to be sensitive to Hg2+ and Pb2+ ions with a detection limit as low as 53 and 16 nM, respectively. The proposed method was found to be useful for colorimetric detection of heavy metal ions in aqueous medium. © 2014 American Chemical Society. Source

Subramanian N.H.,Metrohm India Ltd. | Manigandan P.,Metrohm India Ltd. | Wille A.,Metrohm Ltd
Journal of Chromatographic Science | Year: 2011

This work describes a new method for the determination of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) in water matrices by suppressed conductivity detection. Separation was achieved by isocratic elution on a reversed-phase column thermostated at 45°C using an aqueous mobile phase containing boric acid and acetonitrile. The PFOA and PFOS content in the water matrix were quantified by a pre-concentration technique. For the concentration range of 1 to 15 ng/mL and 2 to 30 ng/mL, the linear calibration curve for PFOA and PFOS yielded coefficients of determination (R2) of 0.9995 and 0.9985, respectively. The relative standard deviations were smaller than 1.5% for PFOA and PFOS. The retention-time precision of four consecutive 12 h injections was smaller than 0.641% and 0.818%, respectively. The presence of common divalent cations, such as calcium, magnesium, and iron in water matrices impairs PFOS recovery. This drawback was overcome by applying inline matrix elimination method. The optimized method was successfully applied for drinking water, ground water, and seawater samples. Source

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