Preparation and characterization of starch grafted with toluene poly (propylene oxide) diisocyanate

Amylopectin-rich starch samples (Amidex 4001 Corn Products Brasil Ingredientes Industriais Ltda.) were grafted with polyethers with the purpose of obtaining new materials for application as solid polymeric electrolytes. Grafting reaction was performed by the addition of starch dissolved in DMSO to toluene poly(propylene oxide) diisocyanate (Resibras) dissolved in the same solvent. This reaction produced a film with good mechanical properties. The film samples were characterized by 13C-NMR, FTIR, DSC, X-Ray and SEM. The FTIR spectrum shows a sharp NH band and a very small urethane band. The 13C-NMR spectrum revealed a peak at 20 ppm, that can be attributed to the CH3 of the polyether chain, and two small peaks at 117 and 140 ppm, attributed to the aromatic ring. The X-ray diffractograms also indicated that after the grafting reaction, the samples of amylopectin-rich starch are more amorphous. Moreover, the glass transition temperature (Tg) dropped from 50 °C to -11 °C. These results indicate formation of grafted products and the low Tg of the samples suggests that polyether-grafted starch is a good candidate to obtain solid polymeric electrolytes

Application Of Ni(ii)-imprinted Cross-linked Poly(methacrylic Acid) Synthesised Through Double-imprinting Method For The On-line Preconcentration Of Ni(ii) Ions In Aqueous Media

The present paper describes the feasibility of on-line preconcentration of nickel ions from aqueous medium on Ni(II)-imprinted cross-linked poly(methacrylic acid) (IIP) synthesised through a double-imprinting method and their subsequent determination by FAAS. The proposed method consisted in loading the sample (20.0 mL, pH 7.25) through a mini-column packed with 50 mg of the IIP for 2 min. The elution step was performed with 1.0 mol L-1 HNO3 at a flow rate of 7.0 mL min-1. The following parameters were obtained: quantification limit (QL) - 3.74 μg L-1, preconcentration factor (PF) - 36, consumption index (CI) - 0.55 mL, concentration efficiency (CE) - 18 min-1, and sample throughput - 25 h-1. The precision of the procedure assessed in terms of repeatability for ten determinations was 5.6% and 2.5% for respective concentrations of 5.0 and 110.0 μg L-1. Moreover, the analytical curve was obtained in the range of 5.0-180.0 μg L-1 (r = 0.9973), and a 1.64-fold increase in the method sensitivity was observed when compared with the analytical curve constructed for the NIP (non-imprinted polymer), thus suggesting a synergistic effect of the Ni(II) ions and CTAB on the adsorption properties of the IIP. The practical application of the adsorbent was evaluated from an analysis of tap, mineral, lake and river water. Considering the results of addition and recovery experiments (90.2-100 %), the efficiency of this adsorbent can be ensured for the interference-free preconcentration of the Ni(II) ions. © 2014 © 2014 Taylor & Francis.941010611071Singh, D.K., Mishra, S., (2009) Chromatographia, 70, p. 1539Segatelli, M.G., Santos, V.S., Presotto, A.B.T., Yoshida, I.V.P., Tarley, C.R.T., (2010) React. Funct. Polym, 70, p. 325Wu, G., Wang, Z., Wang, J., He, C., (2007) Anal. Chim. Acta, 582, p. 304Oliveira, F.M., Somera, B.F., Ribeiro, E.S., Segatelli, M.G., Yabe, M.J.S., Galunin, E., Tarley, C.R.T., (2013) Ind. Eng. Chem. Res, 52, p. 8550Behbahani, M., Taghizadeh, M., Bagheri, A., Hosseini, H., Salarian, M., Tootoonchi, A., (2012) Microchim Acta, 178, p. 429Krishna, P.G., Gladis, J.M., Rao, T.P., Naidu, G.R., Mol, J., (2005) J. Mol. Recogn, 18, p. 109Ávila, T.C., Segatelli, M.G., Beijo, L.A., Tarley, C.R.T., (2010) Quím. Nova, 33, p. 301Hoffmann, F., Cornelius, M., Morell, J., Fröba, M., (2006) Angew. Chem., Int. Ed, 45, p. 3216Dai, S., Burleigh, M.C., Ju, Y.H., Gao, H.J., Lin, J.S., Pennycook, S.J., Barnes, C.E., Xue, Z.L., (2000) J. Am. Chem. Soc, 122, p. 992Lu, Y.-K., Yan, X.-P., (2004) Anal. Chem, 76, p. 453Nacano, L.R., Segatelli, M.G., Tarley, C.R.T., (2010) J. Braz. Chem. Soc, 21, p. 419Dai, S., (2001) Chemistry, 7, p. 763Oliveira, F.M., Somera, B.F., Corazza, M.Z., Yabe, M.J.S., Segatelli, M.G., Ribeiro, E.S., Lima, E., Tarley, C.R.T., (2011) Talanta, 85, p. 2417Tarley, C.R.T., Barbosa, A.F., Segatelli, M.G., Figueiredo, E.C., Luccas, P.O., (2006) J. Anal. At. Spectrom, 21, p. 1305Pearson, R.G., (1963) J. Am. Chem. Soc, 85, p. 3533Long, G.L., Voigtman, E.G., Kosinski, M.A., Winefordner, J.D., (1983) Anal. Chem, 55, p. 1432Lata, H., Garg, V.K., Gupta, R.K., (2008) J. Hazard. Mat, 157, p. 503Duran, C., Senturk, H.B., Elci, L., Soylak, M., Tufekci, M., (2009) J. Hazard. Mat, 162, p. 292(2013) Directory 357 from the National Brazilian Environmental Council, Fed. Off. J, , www.mma.gov.br/port/conama/legiabre.cfm?codlege=459Shokrolahi, A., Ghaedi, M., Shabani, R., Montazerozohori, M., Chehreh, F., Soylak, M., Alipour, S., (2010) Food Chem. Toxicol, 48, p. 482Ciftci, H., Yalcin, H., Eren, E., Olcucu, A., Sekerci, M., (2010) Desalination, 256, p. 48Amais, R.S., Ribeiro, J.S., Segatelli, M.G., Yoshida, I.V.P., Luccas, P., Tarley, C., (2007) Separation and Purification Technology, 58, p. 122Jiang, N., Chang, X., Zheng, H., He, Q., Hu, Z., (2006) Anal. Chim. Acta, 577, p. 225Praveen, R.S., Daniel, S., Prasada, R.T., (2005) Talanta, 66, p. 513Ali, A., Ye, Y., Xu, G., Yin, X., Zhang, T., (1999) Microchem. J, 63, p. 365de Alcântara, I.L., Roldan, P.S., Margionte, M.A.L., Castro, G.R., Padilha, C.C.F., Florentino, A.O., Padilha, P.M., (2004) J. Braz. Chem. Soc, 15, p. 36

Investigation On The Performance Of Chemically Modified Aquatic Macrophytes: Salvinia Molesta For The Micro-solid Phase Preconcentration Of Cd(ii) On-line Coupled To Faas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)In this study, a new method for the preconcentration of cadmium ions using modified aquatic macrophytes – Salvinia molesta as biosorbent in an on-line preconcentration system coupled to flame atomic absorption spectrometry (FAAS) was developed. The method is based on preconcentration of 20.0 mL sample at pH 3.75 through 35.0 mg of biosorbent at 10.0 mL min−1 and subsequent elution with 0.5 mol L−1 HNO3. A preconcentration factor of 31-fold, linear dynamic range from 5.0 to 70.0 µg L−1 (r = 0.9996) and detection and quantification limits of 0.15 and 0.51 µg L−1 were obtained. The characterization of the biosorbent chemically modified with NaOH and citric acid, was performed through FTIR and SEM measurements. The method precision was found to be 3.97 % and 1.48 % for 5.0 and 60.0 µg L−1 Cd(II) solutions, respectively. The applicability of method was checked by analysis of different kind of water samples and certified reference material. © 2016, Springer Science+Business Media New York.976863869305552/2013-9, CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico472670/2012-3, CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico481669/2013-2, CNPq, Conselho Nacional de Desenvolvimento Científico e TecnológicoConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq