Biomedical subjects

M S Subramanian

Publications and source records attributed to M S Subramanian.

5 recordsLinked to original sources

PubMed2006

Sequential separation of lanthanides, thorium and uranium using novel solid phase extraction method from high acidic nuclear wastes.

A novel grafted polymer for selective extraction and sequential separation of lanthanides, thorium and uranium from high acidic wastes has been developed by grafting Merrifield chloromethylated (MCM) resin with octyl(phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide (CMPO) (MCM-CMPO). The grafting process is well characterized using FT-IR spectroscopy, (31)P and (13)C CPMAS (cross-polarized magic angle spin) NMR spectroscopy and CHNPS elemental analysis. The influence of various physico-chemical parameters during metal ion extraction by the resin phase are studied and optimized by both static and dynamic methods. The resin shows very high sorption capacity values of 0.960mmolg(-1) for U(VI), 0.984mmolg(-1) for Th(IV), 0.488mmolg(-1) for La(III) and 0.502mmolg(-1) for Nd(III) under optimum HNO(3) medium, respectively. The grafted polymer shows faster rate exchange kinetics (<5min is sufficient for 50% extraction) and greater preconcentration ability, with reusability exceeding 20 cycles. During desorption process, sequential separation of the analytes is possible with varying eluting agents. The developed grafted resin has been successfully applied in extracting Th(IV) from high matrix monazite sand, U(VI) and Th(IV) from simulated nuclear spent fuel mixtures. All the analytical data is based on triplicate analysis and measurements are within 3.5% rsd reflecting the reproducibility and reliability of the developed method.

Lanthanoid Series Elements↗

PubMed2005

A study of the extraction behavior of thallium with tribenzylamine as the extractant.

A simple solvent extraction study for thallium has been conducted based on the extraction of thallium as a chlorocomplex (tetrachlorothallate (III) anion) with tribenzylamine. Radiolabelled Tl (III) was used to study the extraction behavior of thallium. The beta activity of the extracted ion-association complex has been monitored using liquid scintillation counting and Geiger Muller counter. The effect of various diluents such as toluene, chloroform and isobutylmethylketone (MIBK) were studied. The extraction efficiency was 95% when chloroform and MIBK were used as diluents for tribenzylamine at an overall concentration of 0.25 mol dm(-3) NaCl and 0.5 mol dm(-3) H(2)SO(4). The phenomenon of severe chemical quenching was observed with chloroform as the diluent. The recovery of thallium was found to be 95% at varying concentrations ranging from 5 to 20 microg ml(-1) Tl (III) with a relative standard deviation of 2.5%.

Benzylamines↗

PubMed2004

Extraction of U(VI), Th(IV), and La(III) from acidic streams and geological samples using AXAD-16-POPDE polymer.

A new chromatographic extraction method has been developed using Amberlite XAD-16 (AXAD-16) resin chemically modified with (3-hydroxyphosphinoyl-2-oxo-propyl)phosphonic acid dibenzyl ester (POPDE). The chemically modified polymer was characterized by 13C CPMAS and 31P solid-state NMR, Fourier Transform-NIR-FIR-Raman spectroscopy, CHNPS elemental analysis, and thermogravimetric analysis. Extraction studies performed for U(VI), Th(IV), and La(III) showed good distribution ratio ( D) values of approximately 10(3), even under high acidities (1-4 M). Various physiochemical parameters that influence the quantitative metal ion extraction were optimized by static and dynamic methods. Data obtained from kinetic studies revealed that a time duration of < or =10 min was sufficient to achieve complete metal ion extraction. Maximum metal sorption capacity values under optimum pH conditions were found to be 1.38, 1.33, and 0.75 mmol g(-1) for U(VI), Th(IV), and La(III), respectively. Interference studies performed in the presence of concentrated diverse ions and electrolyte species showed quantitative analyte recovery with lower limits of analyte detection being 10 and 20 ng cm(-3) for U(VI) and both Th(IV) and La(III), respectively. Sample breakthrough studies performed on the extraction column showed an enrichment factor value of 330 for U(VI) and 270 for Th(IV) and La(III), respectively. Analyte desorption was effective using 15 cm3 of 1 M (NH4)2CO3 with >99.8% analyte recovery. The analytical applicability of the developed resin was tested with synthetic mixtures mimicking nuclear spent fuels, seawater compositions and real water and geological samples. The rsd values of the data obtained were within 5.2%, thereby reflecting the reliability of the developed method.

Journal Article↗

PubMed2004

Selective extraction of U(VI), Th(IV), and La(III) from acidic matrix solutions and environmental samples using chemically modified Amberlite XAD-16 resin.

A new grafted polymer has been developed by the chemical modification of Amberlite XAD-16 (AXAD-16) polymeric matrix with [(2-dihydroxyarsinoylphenylamino)methyl]phosphonic acid (AXAD-16-AsP). The modified polymer was characterized by a combination of (13)C CPMAS and (31)P solid-state NMR, Fourier transform-NIR-FIR-Raman spectroscopy, CHNPS elemental analysis, and thermogravimetric analysis (TGA). The distribution studies for the extraction of U(VI), Th(IV), and La(III) from acidic solutions were performed using an AXAD-16-AsP-packed chromatographic column. The influences of various physiochemical parameters on analyte recovery were optimized by both static and dynamic methods. Accordingly, even under high acidities (>4 M), good distribution ratio (D) values (10(2)-10(4)) were achieved for all the analytes. Metal ion desorption was effective using 1 mol L(-1) (NH(4))(2)CO(3). From kinetic studies, a time duration of <15 min was sufficient for complete metal ion saturation of the resin phase. The maximum metal sorption capacities were found to be 0.25, 0.13, and 1.49 mmol g(-1) for U(VI); 0.47, 0.39, and 1.40 mmol g(-1) for Th(IV); and 1.44, 1.48, and 1.12 mmol g(-1) for La(III), in the presence of 2 mol L(-1) HNO(3), 2 mol L(-1) HCl, and under pH conditions, respectively. The analyte selectivity of the grafted polymer was tested in terms of interfering species tolerance studies. The system showed an enrichment factor of 365, 300, and 270 for U(VI), Th(IV), and La(III), and the limit of analyte detection was in the range of 18-23 ng mL(-1). The practical applicability of the polymer was tested with synthetic nuclear spent fuel and seawater mixtures, natural water, and geological samples. The RSD of the total analytical procedure was within 4.9%, thus confirming the reliability of the developed method.

Journal Article↗

PubMed1989

Determination of isoniazid in pharmaceutical preparations by reaction with radiochloramine-B.

A method has been developed for the determination of isoniazid (INH) at microgram level in pharmaceutical preparations based on the oxidation of isoniazid by radiochloramine-B. Interference of vitamin C has been overcome by precipitation as lead ascorbate and that of rifampicin and p-aminosalicylic acid by selective extraction. Amounts as low as 25 micrograms of INH can be determined.

Aminosalicylic Acid↗