National Center for Compositional Characterisation of Materials

BARC, India

National Center for Compositional Characterisation of Materials

BARC, India
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Liao P.-H.,National Sun Yat - sen University | Jiang S.-J.,National Sun Yat - sen University | Jiang S.-J.,Kaohsiung Medical University | Sahayam A.C.,National Center for Compositional Characterisation of Materials
Journal of Analytical Atomic Spectrometry | Year: 2012

A simple and efficient cloud point extraction (CPE) procedure has been described for the preconcentration and separation of trace levels of Cd, Sb and Hg simultaneously from water samples for their determination by flow injection vapor generation inductively coupled plasma mass spectrometry (FI-VG-ICP-MS). The method was based on the formation of hydrophobic complexes of Cd, Sb and Hg with ammonium pyrrolidine dithiocarbamate (APDC), followed by their extraction, into a small volume of surfactant-rich phase, using a non-ionic surfactant Triton X-114. The main parameters affecting the extraction process such as concentration of complexing agent and pH, and also the amount of Triton X-114 were optimized. The surfactant-rich phase was dissolved with the carrier solution and then injected into VG-ICP-MS for Cd, Sb and Hg determination. The parameters affecting the vapor generation efficiency were also studied meticulously. Isotope dilution (ID) method was used for quantification work. The limit of detection for Cd, Sb and Hg was 0.002, 0.0006 and 0.005 ng mL -1, respectively. The accuracy of the procedure was verified by analyzing certified reference materials such as NRCC SLRS-4 River Water and NRCC SLEW-2 Estuarine Water reference materials, and also by applying it to a bottled mineral water, reservoir water and tap water samples obtained locally. © 2012 The Royal Society of Chemistry.


Hsu W.-H.,National Sun Yat - sen University | Jiang S.-J.,National Sun Yat - sen University | Jiang S.-J.,Kaohsiung Medical University | Sahayam A.C.,National Center for Compositional Characterisation of Materials
Talanta | Year: 2013

The determination of Cu, As, Hg and Pb in vegetable oils by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) was investigated. The oils were injected in the form of emulsions containing 5% m/v vegetable oil, 1.5% v/v Triton X-100 and 50 μg mL-1 ascorbic acid. Palladium nanoparticles (Pd-NPs) were used as modifier. The interference of 40Ar35Cl+ at arsenic mass m/z 75 was reduced significantly using dynamic reaction cell (DRC). Standard addition and isotope dilution methods were used for the quantifications. The method reported has been applied to the determination of Cu, As, Hg and Pb in selected vegetable oil samples purchased from a local market. The analytical results obtained were in good agreement with those of digested samples analyzed by pneumatic nebulization ICP-MS with 95% confidence according to Student t-test (except for Cu). Precision between sample replicates was better than 10% with the ETV-ICP-MS method. The detection limits obtained from standard addition curves were 0.4, 0.5, 1.1 and 0.4 ng g-1 for Cu, As, Hg and Pb, respectively, in the original oil samples. © 2013 Elsevier B.V.


Yang F.-Y.,National Sun Yat - sen University | Jiang S.-J.,National Sun Yat - sen University | Jiang S.-J.,Kaohsiung Medical University | Sahayam A.C.,National Center for Compositional Characterisation of Materials
Food Chemistry | Year: 2014

Speciation analysis of cobalt in nutritive supplements has been carried out using HPLC and ICP-MS equipped with a membrane desolvation sample introduction system as detector. In this study, cobalt containing compounds, namely Co(II), cyanocobalamin (CN-Cbl) and hydroxylcobalamin (OH-Cbl), were well separated by reversed phase HPLC with a C8-HPLC column as the stationary phase and 8 mmol L-1 ammonium acetate in 22% v/v methanol solution (pH 4) as the mobile phase using isocratic elution. Detection limit was in the range of 0.008-0.014 μg Co L-1 for various Co species. Over 98% of the total cobalt species was extracted in nutritive supplements using a 0.5% v/v HNO3 solution in a microwave field; and the spike recovery was in the range of 92-108% for various species. The HPLC-ICP-MS results showed a satisfactory agreement with the total cobalt concentrations obtained by ICP-MS analysis of completely dissolved samples. © 2013 Elsevier Inc. All rights reserved.


Hsu W.-H.,National Sun Yat - sen University | Jiang S.-J.,National Sun Yat - sen University | Jiang S.-J.,Kaohsiung Medical University | Sahayam A.C.,National Center for Compositional Characterisation of Materials
Analytica Chimica Acta | Year: 2013

Inductively coupled plasma mass spectrometry coupled with ultrasonic slurry sampling electrothermal vaporization (USS-ETV-ICP-MS) has been applied to determine Pd, Rh, Pt and Au in 0.5% m/v slurries of several road dust samples. 2% m/v ammonium pyrrolidine dithiocarbamate (APDC) was used as the modifier to enhance the ion count. The influence of instrument operating conditions, slurry preparation and interferences on the ion count was reported. This method has been applied to the determination of Pd, Rh, Pt and Au in BCR 723 Road Dust and NIST SRM 2709 San Joaquin Soil reference materials and two road dust samples collected locally. The analysis results of the standard reference materials agreed with the certified values. Precision between sample replicates was better than 10% for all the determinations. The method detection limits estimated from standard addition curves were 0.9, 0.4, 0.6 and 0.4ngg-1 for Pd, Rh, Pt and Au, respectively, in original dust samples. © 2013.


Kumar P.V.K.,National Center for Compositional Characterisation of Materials | Suryanarayana M.V.,National Center for Compositional Characterisation of Materials
Journal of Physics B: Atomic, Molecular and Optical Physics | Year: 2011

Hyperfine splittings for the 39K and 41K isotopes and the isotope shift for the 4s 2S 1/2 → 6s 2S 1/2 two-photon transition have been measured using sub-Doppler fluorescence spectroscopy. We have accurately measured the transition isotope shift, and a discrepancy has been found in the earlier reported transition isotope shift value, which has been corrected. The resulting hyperfine splitting values of 418.2 (5) and 230.4 (1.3) MHz for the 39K and 41K isotopes respectively are in agreement with previous measurements. The precision of the absolute frequency values for the two-photon transition has been improved by about two orders. Our measured magnetic dipole constants for the upper 6 2S 1/2 state for the 39K and the 41K isotopes are consistent with the earlier measured values. © 2011 IOP Publishing Ltd.


Hsiao P.-K.,National Sun Yat - sen University | Jiang S.-J.,National Sun Yat - sen University | Sahayam A.C.,National Center for Compositional Characterisation of Materials
Journal of Analytical Atomic Spectrometry | Year: 2011

The determination of B, Al, P, Fe, Ni, Cu, Zn, Cd and Pb in silicon powder by ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) using citric acid as the modifier was investigated. The influences of instrument operating conditions and slurry preparation on the ion signals were studied. A relatively low vaporization temperature of 1900 °C was used, which separated the analyte from the major matrix components that not only improved ion signals significantly but also alleviated the spectral interferences caused by 28Si 29Si+, 28Si16O16O +, 28Si17O18O+ and 38Ar28Si+ on 57Fe+, 60Ni+, 63Cu+ and 66Zn+ determinations. The method has been applied to determine B, Al, P, Fe, Ni, Cu, Zn, Cd and Pb in a 99.999% pure silicon powder sample and four solar grade silicon powder samples using standard addition calibration methods. The concentrations that are in μg g-1 to sub μg g-1 levels were in good agreement with those of digested samples analyzed by pneumatic nebulization membrane desolvation ICP-MS. The precision between sample replicates was better than 9% with USS-ETV-ICP-MS technique. The method detection limit estimated from standard addition curves was about 8, 7, 9, 50, 9, 3, 7, 1 and 0.4 ng g-1 for B, Al, P, Fe, Ni, Cu, Zn, Cd and Pb, respectively, in original silicon samples. © 2011 The Royal Society of Chemistry.


Yi Y.-Z.,National Sun Yat - sen University | Jiang S.-J.,National Sun Yat - sen University | Sahayam A.C.,National Center for Compositional Characterisation of Materials
Journal of Analytical Atomic Spectrometry | Year: 2012

Palladium nanoparticles (Pd-NPs) were used as the modifier for the determination of Zn, As, Cd, Sb, Hg and Pb in biological samples by ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS). The preparation and characterization of palladium nanoparticles (Pd-NPs) is described. Compared to traditional Pd aqueous solution, better ion signals were obtained when Pd-NPs was used as modifier. The influences of instrument operating conditions and slurry preparation on the ion signals were reported. The introduction of dry aerosol with ETV sampling device alleviated the spectral interferences effectively. This method has been applied for the determination of Zn, As, Cd, Sb, Hg and Pb in NIST SRM 1568a Rice Flour and SRM 1573a Tomato Leaves reference materials and two biological samples obtained locally. The analysis results of the reference material agree with the certified values. The results for the real world samples were also found to be in good agreement with the pneumatic nebulization ICP-MS results of the sample solutions. The method detection limits estimated from standard addition curves are in the range 1.9-3.6, 0.2-0.4, 0.5-0.8, 0.1-0.2, 0.4-0.8 and 0.4-0.6 ng g -1 for Zn, As, Cd, Sb, Hg and Pb, respectively, in original samples. © 2012 The Royal Society of Chemistry.


Kiran Kumar P.V.,National Center for Compositional Characterisation of Materials | Suryanarayana M.V.,National Center for Compositional Characterisation of Materials
Optics Communications | Year: 2012

The hyperfine splitting for the 133Cs isotope for the 6s 2S 1/2 → 9s 2S 1/2 transition has been measured using Doppler-free two-photon fluorescence spectroscopy in a gas cell for the first time to our knowledge. The hyperfine splitting between the two components was measured to be 8754 (1) MHz and the magnetic dipole coupling constant (A) for the excited 9s 2S 1/2 level was determined to be 109.7 (3) MHz for the 133Cs isotope. The measured values are in good agreement with the earlier reported results. © 2011 Elsevier B.V. All rights reserved.


Sahayam A.C.,National Center for Compositional Characterisation of Materials | Chaurasia S.C.,National Center for Compositional Characterisation of Materials | Venkateswarlu G.,National Center for Compositional Characterisation of Materials
Analytica Chimica Acta | Year: 2010

A dry ashing procedure is developed for the determination of As in organic rich matrices such as wheat flour, lichen and tobacco leaves. The volatility of As during dry ashing is avoided by the addition of palladium nitrate [Pd(NO3)2]. The recovery of both As(III) and As(V) is found to be near quantitative. The residue after dry ashing is dissolved in nitric acid (HNO3) and analysed by inductively coupled plasma-mass spectrometry (ICP-MS). The process blank and limit of detection (LOD) are 11 and 6.6 ng g-1, respectively. The procedure is applied for the determination of As in certified reference materials namely wheat flour NIST SRM 1567a (National Institute of Standards and Technology Standard Reference Material), lichen BCR CRM 482 (Institute for Reference Materials, European Commission) and Virginia tobacco leaves CTA-VTL-2 (Poland Academy of Sciences). The results obtained by the present procedure are in good agreement with the certified values and also determined after complete dissolution of samples using closed microwave digestion. © 2009 Elsevier B.V. All rights reserved.


Shekhar R.,National Center for Compositional Characterisation of Materials
Talanta | Year: 2012

A method has been developed to improve the sensitivity of the electrolyte cathode discharge atomic emission spectrometry (ELCAD-AES) for mercury determination. Effects of various low molecular weight organic solvents at different volume percentages as well as at different acid molarities on the mercury signal were investigated using ELCAD-AES. The addition of few percent of organic solvent, acetic acid produced significant enhancement in mercury signal. Acetic acid of 5% (v/v) with the 0.2 M acidity has been found to give 500% enhancement for mercury signal in flow injection mode. Under the optimized parameters the repeatability, expressed as the percentage relative standard deviation of spectral peak area for mercury with 5% acetic acid was found to be 10% for acid blank solution and 5% for 20 ng/mL mercury standard based on multiple measurements with a multiple sample loading in flow injection mode. Limit of detection of this method was determined to be 2 ng/mL for inorganic mercury. The proposed method has been validated by determining mercury in certified reference materials, Tuna fish (IAEA-350) and Aquatic plant (BCR-060). Accuracy of the method for the mercury determination in the reference materials has been found to be between 3.5% and 5.9%. This study enhances the utility of ELCAD-AES for various types of biological and environmental materials to quantify total mercury at very low levels. © 2012 Elsevier B.V. All rights reserved.

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