On-line preconcentration and determination of copper, lead and chromium(VI) using unloaded polyurethane foam packed column by flame atomic absorption spectrometry in natural waters and biological samples
ABSTRACT A simple, sensitive and low cost, flow injection time-based method was developed for on-line preconcentration and determination of copper, lead and chromium(VI) at sub mug l(-1) levels in natural waters and biological samples. At the optimum pH, the on-line formed metal-ammonium pyrrolidine dithiocarbamate (APDC) complexes were sorbed on the unloaded commercial polyurethane foam (PUF), and subsequent eluted quantitatively by isobutylmethylketone and determined by flame atomic absorption spectrometry (FAAS). All chemical, and flow injection variables were optimized for the quantitative preconcentration of each metal and a study of interference level of various ions was also carried out. The system offered improved flexibility, low backpressure and applicability to all the studied metals. At a sample frequency of 36 h(-1) and a 60 s preconcentration time, the enhancement factor was 170, 131 and 28, the detection limit was 0.2, 1.8 and 2.0 mug l(-1), and the precision, expressed as relative standard deviation (s(r)), was 2.8 (at 10 mug l(-1)), 3.4 (at 50 mug l(-1)) and 3.6% (at 50 mug l(-1)) for Cu(II), Pb(II) and Cr(VI), respectively. The accuracy of the developed method was sufficient and evaluated by the analysis of certified reference materials and spiked water samples. Finally, the method was applied to the analysis of environmental samples.
Full-textDOI: · Available from: George Zachariadis, Aug 13, 2015
- SourceAvailable from: Davoodbasha MubarakAli
[Show abstract] [Hide abstract]
- "Several studies focus on the design and synthesis of chemosensors for the analysis of toxic or heavy-metal ions such as Hg 2+ , Pb 2+ , and so on (Anthemidis et al., 2002; Gokel et al., 2004; Kumar et al., 2008; Duong and Kim, 2010; Kobayashi et al., 2010; Chen et al., 2011; Zhang et al., 2011; Formica et al., 2012; Kim et al., 2012b; Kim et al., 2012a; Sahoo et al., 2012). "
ABSTRACT: Thiophene-based diimine (R1) and monoimine (R2) were synthesized in a single step, and their cation binding affinity was tested using colorimetric and UV-vis spectral studies. R1 selectively shows a colorimetric turn-on response for Pb(2+) , Hg(2+) ions and colorimetric turn-off with Sn(2+) ions, and R2 shows visual response for Cu(2+) and Hg(2+) over other examined metal ions in aqueous medium. R1 forms 1:1 complex with Pb(2+) , Hg(2+) , and Sn(2+) and exhibits fluorescence quenching, whereas R2 shows 2:1 complex with Hg(2+) , Cu(2+) and shows fluorescence enhancement. The structural and electronic properties of the sensors and their metal complexes were also investigated using Density Functional Theory calculations. R2 was also successfully demonstrated as a fluorescent probe for detecting Cu(2+) ions in living cells. Copyright © 2014 John Wiley & Sons, Ltd.Journal of Molecular Recognition 03/2014; 27(3):151-9. DOI:10.1002/jmr.2343 · 2.34 Impact Factor
[Show abstract] [Hide abstract]
- "In addition, it has some extra advantages: large availability, easy recovery of the solid phase, attainability of large preconcentration factors and facility for separation using various systems. The most convenient sorbent materials are C18 (Ali et al., 1999), amberlite or Chelex (Ferreira et al., 2000), activated carbon (de Pena et al., 1995) and polyurethane foam (PUF) (Anthemidis et al., 2002). The PUF is an excellent sorbent material due to its high available surface area and extremely low cost. "
ABSTRACT: The polyhydroxyl-polyurethane foam (PPF) was used as a new sorbent for separation, preconcentration and determination of manganese and iron ions in natural samples. Experimental conditions for effective separation of trace levels of the metal ions were optimized with respect to different experimental parameters in batch and dynamic processes. The maximum sorption of Mn(II) and Fe(III) was in the pH range of 6–8. The kinetics of sorption of the Mn(II) and Fe(III) by the PPF was found to be fast with an average value of half-life of sorption (t1/2) of 11.7 min. The sorption capacity of PPF was 8.7 μmol g−1 and the recovery of tested ions 99–100% was achieved. The lower detection limit, 0.08 μg L−1 was evaluated using spectrophotometric method. The relative standard deviation (RSD) under optimum conditions is 1.3% (n = 5). The bonding of the studied metal ions by the PPF is useful for the removal of metal contamination from real samples.10/2013; 14(1):60–66. DOI:10.1016/j.jaubas.2012.09.004
[Show abstract] [Hide abstract]
- "Lead in wine and water was preconcentrated on a mini-column filled with polyurethane form modified with 2-(2-benzothiazolylazo)-p-cresol  or Pb-Spec resin  for the FAAS determination of lead. For the determination of lead in environmental samples, the on-line formed lead-pyrrolidinedithio carbamate complex was sorbed on the polyurethane form, subsequently eluted by 2-methyl-4-pentanone, and determined by FAAS. "
ABSTRACT: A flow injection method has been developed for the direct determination of free available Pb(II). The method is based on the chemical sorption of Pb(II), from pH7 solutions, on a column packed of chelating resin. The retained complex was afterwards eluted with hydrochloric acid followed by hydride generation with reduction by tetrahydroborate. The preconcentration system proposed in this paper allows the elimination of great part of the saline content in the sample. A thorough scrutiny was made for chemical variables and FI parameters. With a sampling volume of 10.5 mL, quantitative retention of Pb (II) was obtained, along with an enrichment factor of 40 and a sampling frequency of 15 h(-1). The detection limit, defined as 3 times the blank standard deviation (3sigma), was 0.0031 ngml(-1). The precision was characterized by an RSD value of 3.78% (at the 4 ng.ml(-1) level, n = 11). The developed method has been applied to the determination of trace Pb in three standard reference materials. Accuracy was assessed through comparing the results with the accepted values.Journal of Automated Methods and Management in Chemistry 09/2009; 2009:101679. DOI:10.1155/2009/101679 · 1.00 Impact Factor