4,012 research outputs found
High-performance Liquid Chromatographic Stationary Phases Based On Polysiloxanes With Different Chain Lengths Thermally Immobilized On Silica Supports
No full textReversed phases for high-performance liquid chromatography (RP-HPLC) were obtained by thermal immobilization of polysiloxanes having different length chains (C1, C8 and C14) onto HPLC silica particles. The importance both of percent loading of the stationary phase promoted by each immobilization procedure and of the length of the lateral chain of the polymer on the chromatographic performances of the phases obtained is compared and discussed. © 2006 Elsevier B.V. All rights reserved.111901/02/15135139Bien-Vogelsang, U., Deege, A., Figge, H., Köhler, J., Schomburg, G., (1984) Chromatographia, 19, p. 170Nyholm, L.M., Markides, K.E., (1998) J. Chromatogr. A, 813, p. 11Köhler, J., (1986) Chromatographia, 21, p. 573Silva, M.C.H., Jardim, I.C.S.F., (1998) J. Liq. Chromatogr. Rel. Technol., 21, p. 2447Jardim, I.C.S.F., Collins, K.E., Anazawa, T.A., (1999) J. Chromatogr. A, 849, p. 299Morais, L.S.R., Jardim, I.C.S.F., (2005) J. Chromatogr. A, 1073, p. 127Collins, K.E., Sá, A.L.A., Bottoli, C.B.G., Collins, C.H., (2001) Chromatographia, 53, p. 661Collins, K.E., Bottoli, C.B.G., Vigna, C.R.M., Bachmann, S., Albert, K., Collins, C.H., (2004) J. Chromatogr., 43, p. 1020Schomburg, G., Köhler, J., Figge, H., Deege, A., Bien-Vogelsang, U., (1984) Chromatographia, 18, p. 265Ohmacht, R., Kele, M., Matus, Z., (1989) Chromatographia, 28, p. 19Tonhi, E., Bachmann, S., Albert, K., Jardim, I.C.S.F., Collins, K.E., Collins, C.H., (2002) J. Chromatogr. A, 948, p. 97Tonhi, E., Collins, K.E., Collins, C.H., (2002) J. Chromatogr. A, 948, p. 109Tonhi, E., Collins, K.E., Collins, C.H., (2005) J. Chromatogr. A, 1075, p. 87Collins, K.E., Franchon, A.C., Jardim, I.C.S.F., Radovanovic, E., Gonçalves, M.C., (2000) LC-GC, 18, p. 106Fonseca, D.A., Gutiérrez, H.R., Collins, K.E., Collins, C.H., (2004) J. Chromatogr. A, 1030, p. 14
Preparation, Characterization And Application Of C8 Type Stationary Phases Modified By Metallic Oxides For Liquid Chromatography [preparação, Caracterização E Aplicaç ão De Fases Estacionárias Tipo C8 Modificadas Por óxidos Metálicos Para Cromatografia Líquida]
No full textThis work describes three C8-stationary phases for high performance liquid chromatography based on silica metallized with ZrO2, TiO2 or Al2O3 layers, having poly(methyloctylsiloxane) immobilized onto their surfaces. The stationary phases were characterized using XRF, XAS, FTIR, SEM and elemental analysis to determine the physical characteristics of the oxide and polysiloxane layers formed on the surfaces and chromatographically to evaluate the separation parameters. The results show the changes on the silica surface and allowed proposing a structure for the oxide layer, being observed tetrahedral and octahedral structures, what is completely new in the literature. The formation of a homogeneous layer of metallic oxide (TiO2 and ZrO2) was observed on the silica. The C8-titanized and C8-aluminized stationary phases presented good chromatographic performances, with good values of asymmetry and efficiency. All stationary phase presented few loss of the polymeric layer after the HPLC, indicating that this layer is well attached on the metalized support.36811311138Collins, C.H., Braga, G.L., Bonato, P.S., (2006) Fundamentos De Cromatografia, , Editora Unicamp: CampinasTonhi, E., Collins, K.E., Jardim, I.C.S.F., Collins, C.H., (2002) Quim. Nova, 25, p. 616Tonhi, E., Collins, K.E., Jardim, I.C.S.F., Collins, C.H., (2006) J. Chromatogr. A, 1119, p. 135Poole, C.F., Poole, S.K., (1991) Contemporary Practice of Chromatography, , Elsevier: AmsterdamSnyder, L.R., Kirkland, J.J., Glajch, J.L., (1997) Practical HPLC Method Development, , 2a ed., Wiley: New YorkGushikem, Y., Kubota, L.T., (1991) Analyst, 116, p. 281Gushikem, Y., Baccan, N., Peixoto, C.R.M., (1992) Analyst, 117, p. 1029Gushikem, Y., Castro, S.C., Prado, L.L.L., Nascente, P.A.P., (2000) J. Mater. Sci., 35, p. 449Chiaradia, M.C., (2005) Dissertação De Mestrado, , Universidade Estadual de Campinas, BrasilCollins, C.H., Silva, C.R., Faria, A.M., Collins, K.E., Jardim, I.C.S.F., (2009) J. Braz. Chem. Soc., 20, p. 604Silva, R.B., Collins, C.H., (1999) J. Chromatogr. A, 845, p. 417Melo, L.F.C., Jardim, I.C.S.F., (1999) J. Chromatogr. A, 845, p. 423Faria, A.M., Collins, K.E., Collins, C.H., (2006) J. Chromatogr. A, 1122, p. 144Faria, A.M., Collins, K.E., Collins, C.H., (2007) J. Chromatogr. A, 1156, p. 51Faria, A.M., Collins, K.E., Collins, C.H., (2008) Chromatographia, 67, p. 357Faria, A.M., Silva, C.R., Collins, C.H., Jardim, I.C.S.F., (2008) J. Sep. Sci., 31, p. 953Gushikem, Y., (2001) Colloids Surf., A, 178, p. 135Jardim, I.C.S.F., Collins, K.E., Anazawa, T.A., (1999) J. Chromatogr. A, 849, p. 299Melo, L.F.C., Collins, C.H., Collins, K.E., Jardim, I.C.S.F., (2000) J. Chromatogr. A, 869, p. 129Silva, R.B., Collins, K.E., Collins, C.H., (2000) J. Chromatogr. A, 869, p. 137Bottoli, C.B.G., (2002) Tese De Doutorado, , Universidade Estadual de Campinas, BrasilGonçalvez, J.E., Castro, S.C.C., Ramos, A.Y., Alves, M.C.M., Gushikem, Y., (2001) J. Electron Spectrosc. Relat. Phenom., 114-116, p. 307Collins, K.E., Dimiras, A.B., De Camargo, V.R., Collins, C.H., (2006) Microporous Mesoporous Mater, 89, p. 246Jenkins, R., (1999) X-Ray Fluorescence Spectrometry, , 2a ed., Wiley: New YorkRaghavan, S., Wang, H., Porter, W.D., Dinwidde, R.B., Mayo, M.J., (2001) Acta Mater, 49, p. 169Wells, A.F., (1984) Structural Inorganic Chemistry, , 5a ed., Clarendon Press: OxfordStevenson, R., (1986) Zirconia Zirconia Ceramics, , 2nd ed., Magnesium Elektron: TwickenhamRuiz-López, M.F., Muñoz-Páez, A., (1991) J. Phys. Condens. Matter, 3, p. 8981Nawrocki, J., (1997) J. Chromatogr. A, 779, p. 29Silverstein, R.M., Bassler, G.C., Morrill, T.C., (1978) Spectrometric Identification of Organic Compounds, , 3a ed., Wiley: New YorkFrancisco, M.S.P., Gushikem, Y., (2002) J. Mater. Chem., 12, p. 2552Wang, S.W., (1996) Mater. Lett., 28, p. 43
Product Speciation And Aquation After The Reaction Of 51cr(vi) With Concentrated Hcl Or H2so4
No full textThe present study was undertaken to investigate the reaction of Cr(VI) in concentrated hydrochloric acid or concentrated sulfuric acid, as well as to evaluate the products formed when complexing anions are present during the reaction. The results show that trace level Cr(VI) is rapidly reduced to Cr(III) in both 37% HCl and 98% H2SO4 in the absence of conventional reducing agents and that the initial products are, respectively, CrCl3(H2O)3 and Cr(H2O)2(SO4)- 2, which undergo slow aquation reactions at pH 1, giving Cr(H2O)3+ 6.502315320Nriagu, J.O., Nieboer, E., Chromium in the natural and human environments (1988) Advances in Environmental Science and Technology, 20. , John Wiley, New YorkPezzin, S.H., Archundia, C., Collins, C.H., Collins, K.E., (1997) Radiochim. Acta, 77, p. 91Pezzin, S.H., Archundia, C., Collins, C.H., Collins, K.E., (1998) J. Radioanal. Nucl. Chem., 236, p. 209Archundia, C., Rivera, J.F.L., Collins, C.H., Collins, K.E., (1995) J. Radioanal. Nucl. Chem., 195, p. 363Pavel, J., Kliment, J., Stoerk, S., Suter, O., (1985) Fresenius Z. Anal. Chem., 321, p. 587Stollenwerk, K.G., Grove, D.B., (1985) J. Environ. Qual., 14, p. 396Collins, C.H., Pezzin, S.H., Rivera, J.F.L., Bonato, P.S., Windmöller, C.C., Archundia, C., Collins, K.E., (1997) J. Chromatogr. A, 781, p. 469De Andrade, J.C., Collins, K.E., (1981) Quím. Nova, 4, p. 89Collins, K.E., Bonato, P.S., Archundia, C., De Queiroz, M.E.L.R., Collins, C.H., (1988) Chromatographia, 26, p. 16
The Challenges Of The Analysis Of Basic Solutes By Reversed Phase Liquid Chromatography: Some Possible Approaches For Improved Separations [o Desafio De Analisar Solutos Básicos Por Cromatografia Líquida Em Modo Reverso: Algumas Alternativas Para Melhorar As Separações]
No full textThis review considers some of the difficulties encountered with the analysis of basic solutes using reversed-phase chromatography, such as detrimental interaction with stationary phase silanol groups. Methods of overcoming these problems in reversed-phase separations, by judicious selection of the stationary phase and mobile phase conditions, are discussed. Developments to improve the chemical and thermal stability of stationary phases are also reviewed. It is shown that substantial progress has been made in the manufacturing of stationary phases, enabling their use over a wide variety of experimental conditions. In addition, general measures to significantly extend their lifespan are discussed.3559931003McCalley, D.V., (2010) J. Chromatogr., A, 1217, p. 858Welch, C.J., Wu, N., Biba, M., Hartman, R., Brkovic, T., Gong, X., Helmy, R., Zhou, L., (2010) Trends Anal. Chem., 29, p. 667McCalley, D.V., (2008) Adv. Chromatogr., 46, p. 305Tonhi, E., Collins, K.E., Jardim, I.C.S.F., Collins, C.H., (2002) Quim. Nova, 25, p. 616Silva, C.R., Jardim, I.C.S.F., Collins, C.H., Airoldi, C., (2004) Quim. Nova, 27, p. 270Collins, C.H., Silva, C.R., Faria, A.M., Collins, K.E., Jardim, I.C.S.F., (2009) J. Braz. Chem. Soc., 20, p. 604Faria, A.M., Collins, C.H., Jardim, I.C.S.F., (2009) J. Braz. Chem. Soc., 20, p. 1385Maldaner, L., Collins, C.H., Jardim, I.C.S.F., (2010) Quim. Nova, 33, p. 1559Borges, E.M., Bottoli, C.B.G., Collins, C.H., (2010) Quim. Nova, 33, p. 945Kazakevich, Y., Lobrutto, R., (2007) HPLC for Pharmaceutical Scientists, , John Wiley & Sons: HobokenHinshaw, J.V., (2010) LCGC North Am., 28, p. 952Hinshaw, J.V., (2010) LCGC North Am., 28, p. 874Dolan, W.D., (2011) LCGC North Am., 29, p. 318Maldaner, L., Jardim, I.C.S.F., (2009) Quim. Nova, 32, p. 214Wu, N., Clausen, A., (2007) J. Sep. Sci., 30, p. 1167Chiaradia, M.C., Collins, C.H., Jardim, I.C.S.F., (2008) Quim. Nova, 31, p. 623Gosetti, F., Mazzucco, E., Zampieri, D., Gennaro, M.C., (2010) J. Chromatogr., A, 1217, p. 3929Marchand, D.H., Carr, P.W., McCalley, D.V., Neue, U.D., Dolan, J.W., Snyder, L.R., (2011) J. Chromatogr., A, 1218, p. 7110Vynuchalová, K., Jandera, P., (2011) Anal. Lett., 44, p. 1640Németha, T., Haghedoorena, E., Noszálc, B., Hoogmartensa, J., Adams, E., (2008) J. Chemometrics, 22, p. 178Lesellier, E., West, C., (2007) J. Chromatogr. A, 1158, p. 329McCalley, D., (2010) J. Chromatogr., A, 1217, p. 858Welch, C.J., Wu, N., Biba, M., Hartman, R., Brkovic, T., Gong, X., Helmy, R., Zhou, L., (2010) Trends Anal. Chem., 29, p. 667McCalley, D.V., (2008) Adv. Chromatogr., 46, p. 305Tonhi, E., Collins, K.E., Jardim, I.C.S.F., Collins, C.H., (2002) Quim. Nova, 25, p. 616Silva, C.R., Jardim, I.C.S.F., Collins, C.H., Airoldi, C., (2004) Quim. Nova, 27, p. 270Collins, C.H., Silva, C.R., Faria, A.M., Collins, K.E., Jardim, I.C.S.F., (2009) J. Braz. Chem. Soc., 20, p. 604Faria, A.M., Collins, C.H., Jardim, I.C.S.F., (2009) J. Braz. Chem. Soc., 20, p. 1385Maldaner, L., Collins, C.H., Jardim, I.C.S.F., (2010) Quim. Nova, 33, p. 1559Borges, E.M., Bottoli, C.B.G., Collins, C.H., (2010) Quim. Nova, 33, p. 945Kazakevich, Y., Lobrutto, R., (2007) HPLC for Pharmaceutical Scientists, , John Wiley & Sons: HobokenHinshaw, J.V., (2010) LCGC North Am., 28, p. 952Hinshaw, J.V., (2010) LCGC North Am., 28, p. 874Dolan, W.D., (2011) LCGC North Am., 29, p. 318Maldaner, L., Jardim, I.C.S.F., (2009) Quim. Nova, 32, p. 214Wu, N., Clausen, A., (2007) J. Sep. Sci., 30, p. 1167Chiaradia, M.C., Collins, C.H., Jardim, I.C.S.F., (2008) Quim. Nova, 31, p. 623Gosetti, F., Mazzucco, E., Zampieri, D., Gennaro, M.C., (2010) J. Chromatogr., A, 1217, p. 3929Marchand, D.H., Carr, P.W., McCalley, D.V., Neue, U.D., Dolan, J.W., Snyder, L.R., (2011) J. Chromatogr., A, 1218, p. 7110Vynuchalová, K., Jandera, P., (2011) Anal. Lett., 44, p. 1640Németha, T., Haghedoorena, E., Noszálc, B., Hoogmartensa, J., Adams, E., (2008) J. Chemometrics, 22, p. 178Lesellier, E., West, C., (2007) J. Chromatogr., A, 1158, p. 32
Preparation Of Stationary Phases For Reversed-phase High-performance Liquid Chromatography Using Thermal Treatments At High Temperature
No full textBatches of poly(methyloctylsiloxane) (PMOS)-loaded silica were prepared by deposition from a solution of PMOS into the pores of HPLC silica. Portions of PMOS-loaded silica were subjected to a thermal treatment at 100 °C for 24 h (condition 1) in a tube furnace under a nitrogen atmosphere. After that, the material was heated for 4 h at higher temperatures (150-400 °C) (condition 2). Heating at higher temperatures produces polymer bilayers. Non-immobilized and thermally treated stationary phases were characterized by percent carbon, 29Si cross-polarization magic angle spinning nuclear magnetic resonance spectroscopy and reversed-phase chromatographic performance. The results show that thermal treatment between 150 and 300 °C accelerates the immobilization process, possibly due to some bond breaking of the polysiloxane, with formation of strong linkages to the surface of the support, resulting in more complete coverage of the silica. The chromatographic results show an improvement of efficiency with the increase of the temperature of condition 2 up to 300 °C and an increase in the resolution of the components, mainly for the phase heated at 300 °C. Such results demonstrate that a two-step thermal treatment (100 °C then 150-300 °C) produces stationary phases with good properties for use in reversed-phase high-performance liquid chromatography. © 2007 Elsevier B.V. All rights reserved.11561-2 SPEC. ISS.6067Schomburg, G., (1991) Trends Anal. Chem., 10, p. 163Petro, M., Berek, D., (1993) Chromatographia, 37, p. 549Jardim, I.C.S.F., Collins, K.E., Collins, C.H., (2004) Microchem. J., 77, p. 191Anazawa, T.A., Jardim, I.C.S.F., (1994) J. Liq. Chromatogr., 17, p. 1265Collins, K.E., Granja, M.L.M.M., Pereira, R.G., Anazawa, T.A., Jardim, I.C.S.F., (1997) Chromatographia, 45, p. 99Mano, E.B., Mendes, L.C., (1999) Introdução a Polímeros. second revised ed., , Edgard Blücher, São PauloPetsev, N.D., Perov, G.I., Alexandrova, M.D., (1985) Chi. Dimitov, Chromatographia, 20, p. 228Gawdizik, J., (1991) Chromatographia, 31, p. 258Bemgard, A., Blomberg, L.G., (1987) J. Chromatogr., 395, p. 125Chuang, C.H., Shanfield, H., Zlatkis, A., (1987) Chromatographia, 23, p. 169Markides, K., Blomberg, L., Buijten, J., Wännman, T., (1983) J. Chromatogr., 267, p. 29Schomburg, G., Köhler, J., Figge, H., Deege, A., Bien-Vogelsang, U., (1984) Chromatographia, 18, p. 265Jardim, I.C.S.F., Collins, K.E., Anazawa, T.A., (1999) J. Chromatogr. A, 849, p. 299Bottoli, C.B.G., Vigna, C.R.M., Fischer, G., Albert, K., Collins, K.E., Collins, C.H., (2004) J. Chromatogr., 1030, p. 217Bottoli, C.B.G., Collins, K.E., Collins, C.H., (2003) J. Chromatogr. A, 987, p. 87Collins, K.E., Bottoli, C.B.G., Vigna, C.R.M., Bachmann, S., Albert, K., Collins, C.H., (2004) J. Chromatogr. A, 1029, p. 43Morais, L.S.R., Jardim, I.C.S.F., (2005) J. Chromatogr. A, 1073, p. 127Lopes, N.P., Collins, K.E., Jardim, I.C.S.F., (2003) J. Chromatogr. A, 987, p. 77Tonhi, E., Collins, K.E., Collins, C.H., (2005) J. Chromatogr. A, 1075, p. 87Faria, A.M., Collins, K.E., Collins, C.H., (2006) J. Chromatogr. A, 1122, p. 114Pozzebon, J.M., Queiroz, S.C.N., Melo, L.F.C., Kapor, M.A., Jardim, I.C.S.F., (2003) J. Chromatogr. A, 987, p. 381Ohmacht, R., Kele, M., Matus, Z., (1989) Chromatographia, 28, p. 19Collins, K.E., Sá, A.L.A., Bottoli, C.B.G., Collins, C.H., (2001) Chromatographia, 53, p. 661Bottoli, C.B.G., Chaudhry, Z.F., Fonseca, D.A., Collins, K.E., Collins, C.H., (2002) J. Chromatogr. A, 948, p. 121Collins, K.E., Franchon, A.C., Jardim, I.C.S.F., Radovanovic, E., Gonçalves, M.C., (2000) LC-GC, 18, p. 106Bachmann, S., Melo, L.F.C., Silva, R.B., Anazawa, T.A., Jardim, I.C.S.F., Collins, K.E., Collins, C.H., Albert, K., (2001) Chem. Mater., 13, p. 1874Snyder, L.R., Kirkland, J.J., (1979) Introduction to Modern Liquid Chromatography. second ed., , Wiley, New YorkLopes, N.P., Collins, K.E., Jardim, I.C.S.F., (2004) J. Chromatogr. A, 1030, p. 225Nawrocki, J., (1991) Chromatographia, 31, p. 177Kirkland, J.J., Boyes, B.E., DeStefano, J.J., (1994) Am. Lab., 26, p. 3
Reduction Of Trace Quantities Of Chromium (vi) By Strong Acids
No full textThe chemical behavior of Cr(VI) at low concentrations (10-4 to 10-7 mol L-1) in several strong acids was studied using high specific activity 51Cr(VI) as a tracer. The speciation of the products from these systems was carried out by ion exchange chromatography with stepwise elution. The results show that trace quantities of Cr(VI), monitored by means of radiochromium (51Cr), are reduced in the presence of mineral acids such as perchloric, hydrochloric, hydrofluoric, sulfuric, nitric and trifluoromethanesulfonic acids, even in the absence of conventional reducing agents, producing different measureable Cr(III) species, depending on the acid anion. Detailed studies of the reduction of low concentrations of Cr(VI) with nitric acid have shown that the relative rate of reduction increases as the concentration of the acid increases or as the concentration of the Cr(VI) decreases.1515865Weeks, M.E., Leicester, H.M., (1968) Discovery of the Elements, 7th Ed., , American Chemical Society: EastonFeigl, F., (1943) J. Chem. Educ., 20, p. 240Westheimer, F.H., (1949) Chem. Rev., 45, p. 419Wiberg, K.B., (1965) Oxidation in Organic Chemistry, Part A, , Academic: New YorkCainelli, G., Cardillo, G., (1984) Chromium Oxidations in Organic Chemistry, , Springer-Verlag: BerlinDas, A.K., (2001) Oxid. Commun., 24, p. 321Beattie, J.K., Haight Jr., G.P., (1972) Prog. Inorg. Chem., 17, p. 93Fendorf, S., Wienlinga, B.W., Hansel, C.M., (2000) Int. Geol. Rev., 42, p. 691Smith, G.F., (1934) Ind. Eng. Chem. Anal. Edition, 6, p. 229Bobtelsky, M., Glasner, A., (1948) J. Chem. Soc., p. 1376Ho, W.-H., (1979) Proc. Natl. Sci. Counc. ROC, 4, p. 1Archundia, C., Collins, C.H., Collins, K.E., (1990) J. Radioanal. Nucl. Chem. Lett., 146, p. 49Archundia, C., Bonato, P.S., Lugo Rivera, J.F., Mascioli, L.C., Collins, C.H., Collins, K.E., (1993) Sci. Total Environ., 130-131, p. 231Archundia, C., Lugo Rivera, J.F., Collins, K.E., Collins, C.H., (1995) J. Radioanal. Nucl. Chem. Art., 195, p. 363Pezzin, S.H., Archundia, C., Collins, C.H., Collins, K.E., (1997) Radiochim. Acta, 77, p. 91Khan, Z., Hashmi, A.A., Din, K., (1998) Transition Met. Chem., 23, p. 147Pezzin, S.H., Collins, C.H., Archundia, C., Collins, K.E., (1998) J. Radioanal. Nucl. Chem., 236, p. 209Pezzin, S.H., Archundia, C., Collins, K.E., Collins, C.H., (2000) Czech. J. Phys., 50, p. 315Pezzin, S.H., Collins, C.H., Collins, K.E., (2000) Proceedings of the National Meeting on Nuclear Applications, , Rio de Janeiro, Brazil, CD-ROM, paper no. 61Pavel, J., Kliment, J., Stoerk, S., Suter, O., (1985) Fresenius Z. Anal. Chem., 321, p. 587Stollenwerk, K.G., Grove, D.B., (1985) J. Environ. Qual., 14, p. 386Gil, M., Escolar, D., Iza, N., Montero, J.L., (1986) Appl. Spectrosc., 40, p. 1156Tong, J.Y.P., King, E.L., (1960) J. Am. Chem. Soc., 82, p. 3805Espenson, J.H., King, E.L., (1963) J. Am. Chem. Soc., 85, p. 3328Khan, Z., Din, K., (2001) Indian J. Chem., 40 A, p. 528Haight Jr., G.P., Richardson, D.C., Coburn, N.H., (1964) Inorg. Chem., 3, p. 1777Espenson, J.H., (1964) J. Am. Chem. Soc., 86, p. 5101Pezzin, S.H., Collins, C.H., Collins, K.E., (2001) Radiochim. Acta, 89, p. 845House, D.A., (1994) Mechanisms of Inorganic and Organometallic Reactions, p. 97. , Twigg, M. V., ed.Plenum: New YorkSena, M.M., Scarminio, I.S., Collins, K.E., Collins, C.H., (2000) Talanta, 53, p. 453Cruywagen, J.J., Heyns, J.B.B., Rohwer, E.A., (1998) Polyhedron, 17, p. 1741Brito, F., Ascanio, J., Mateo, S., Hernandez, C., Araujo, L., Gili, P., MartinZarza, P., Mederos, A., (1997) Polyhedron, 16, p. 3835Nriagu, J.O., Nieboer, E., (1988) Chromium in the Natural and Human Environments, , Wiley: New YorkCollins, C.H., Pezzin, S.H., Lugo Rivera, J.F., Bonato, P.S., Windmöller, C., Archundia, C., Collins, K.E., (1997) J. Chromatogr. A, 789, p. 469Marques, M.J., Salvador, A., Morales-Rubio, A., De La Guardia, M., (2000) Fresenius. J. Anal. Chem., 367, p. 601Collins, K.E., Bonato, P.S., Archundia, C., De Queiroz, M.E.L.R., Collins, C.H., (1988) Chromatographia, 26, p. 160Collins, C.H., Collins, K.E., Ackerhalt, R.E., (1971) J. Radioanal. Chem., 8, p. 263De Andrade, J.C., Collins, K.E., (1981) Quim. Nova, 4, p. 89Gates, H.S., King, E.L., (1958) J. Am. Chem. Soc., 80, p. 5011Autenrieth, W., (1902) Ber. Deutsch. Chem. Ges., 35, p. 2057Krauss, H.L., Leder, M., Münster, G., (1963) Chem. Ber., 96, p. 3008Finholt, J.E., Ph.D. Thesis, Lawrence Radiation Laboratory Report UCRL-8879, University of California, Berkeley, 1960Collins, C.H., Lanças, F.M., (1982) Radiochem. Radioanal. Letters, 19, p. 117Jones, K.M., Bjerrum, J., (1965) Acta Chem. Scand., 19, p. 974Aggett, J., Udy, D.J., (1970) J. Inorg. Nucl. Chem., 32, p. 2802Chaabouni, M., Chausse, T., Pascal, J.L., Potier, J., (1980) J. Chem. Res. (S), 72Archundia, C., Collins, C.H., Collins, K.E., (1988) Proceedings of the Second General Congress on Nuclear Energy, 2, p. 415. , Rio de Janeiro, BrazilStünzi, H., Marty, W., (1983) Inorg. Chem., 22, p. 2145(1985) Chemical Analysis of Metals and Metal-Bearing Ores, , Annual Book of ASTM Standards, Section 3, Vol.03.05, American Society for Testing and MaterialsPhiladelphiaOttaway, J.M., Fell, G.S., (1986) Pure Appl. Chem., 58, p. 170
A Radiochromatograpic Study Of The Reaction Of 51cro3 With Hydrochloric Acid
No full textThe objective of the present work is to verify the reduction of CrO3 in concentrated hydrochloric acid, using 51Cr as a tracer. For the study, 51CrO3 was added to 37% HCl and maintained under agitation at 20 °C for specified time periods. Aliquots were diluted to approximately pH 2 and analyzed by open column cation and anion chromatography, either immediately or after storage for specified time periods. The separations, which were made by stepwise elution using HClO4 and Ca(ClO4)2 solutions as eluents with fraction collection, followed by counting with a NaI(TI) detector and a single channel analyzer, permitted construction of elution profiles whose peaks were identified by comparison with authentic samples. The results show that CrO3 is reduced to Cr(III) in 37% HCl and that the initial identifiable product is [CrCl3(H2O)3], a product which undergoes slow aquation at pH 2 to [Cr(H2O)4Cl2]+, [Cr(H2O)5Cl]2+ and [Cr(H2O)6]3+.8911-12845847Weeks, M.E., Leicester, H.M., (1968) Discovery of the Elements. 7 th ed., , American Chemical Society, EastonFeigl, F., Spot reaction experiments (1943) J. Chem. Educ., 20, p. 240Krauss, H.L., Leder, M., Münster, G., Zur chemie der chrom(V)-verbindungen (1963) Chem. Ber., 96, p. 3008Bobtelsky, M., Glasner, A., The oxidation of hydrobromic acid by chromic acid in the presence of manganous sulphate (1948) J. Chem. Soc., p. 1376Ho, W.-H., The kinetics of the reaction of chromium(VI) and nitrous acid (1979) Proc. Natl. Sci. Counc. ROC, 4, p. 1Archundia, C., Collins, C.H., Collins, K.E., Speciation of the reaction products of 51Cr/VI/with formic acid (1990) J. Radioanal. Nucl. Chem. Lett., 146, p. 49Khan, Z., Hashmi, A.A., Din, K., Reduction of chromium(VI) by phosphonic acid (1998) Transition Met. Chem., 23, p. 147Smith, G.F., Mixed perchloricsulphuric acids. I. Simultaneous oxidizing and reducing properties of hot concentrated perchloric acid (1934) Ind. Eng. Chem. Anal. Ed., 6, p. 229Archundia, C., Bonato, P.S., Lugo Rivera, J.F., Mascioli, L.C., Collins, C.H., Collins, K.E., Reduction of low concentration Cr(VI) in acid solutions (1993) Sci. Total Environ., 130-131, p. 231Archundia, C., Lugo Rivera, J.F., Collins, K.E., Collins, C.H., Speciation of the products from acid reduction of Cr(VI) (1995) J. Radioanal. Nucl. Chem. Art., 195, p. 363Pezzin, S.H., Archundia, C., Collins, C.H., Collins, K.E., Radiometric and spectrophotometric studies of the behavior of chromium(VI) oxide in concentrated perchloric acid (1997) Radiochim. Acta, 77, p. 91Pezzin, S.H., Collins, C.H., Archundia, C., Collins, K.E., Speciation of the products resulted from the reaction of 51Cr(VI) with concentrated perchloric and trifluoromethanesulfonic acids (1998) J. Radioanal. Nucl. Chem., 236, p. 209Pezzin, S.H., Archundia, C., Collins, K.E., Collins, C.H., Product speciation and aquation after the reaction of 51Cr(VI) with concentrated HCl or H2SO4 (2000) Czech. J. Phys., 50, p. 315Pezzin, S.H., Collins, C.H., Collins, K.E., (2000) Estudo da reação entre 51CrO3 e ácido nitrico concentrado por métodos radiocromatográficos, E01, p. 61. , V Encontro Nacional de Aplicações Nucleares, Rio de Janeiro, Brazil, outubro de 2000, AnaisPavel, J., Kliment, J., Stoerk, S., Suter, O., Preservation of traces of chromium(VI) in water and waste water samples (1985) Fresenius Z. Anal. Chem., 321, p. 587Stollenwerk, K.G., Grove, D.B., Reduction of hexavalent chromium in water samples acidified for preservation (1985) J. Environ. Qual., 14, p. 386Gil, M., Escolar, D., Iza, N., Montero, J.L., Accuracy and linearity in UV spectrophotometry with a liquid absorbance standard (1986) Appl. Spectrosc., 40, p. 1156Collins, C.H., Collins, K.E., Ackerhalt, R.E., Cation exchange separation of 51Cr-labelled species in aqueous Cr(VI)-Cr(III) solution (1971) J. Radioanal. Chem., 8, p. 263De Andrade, J.C., Collins, K.E., Tomeiras de PTFE para uso geral em laboratório (1981) Quím. Nova, 4, p. 89Collins, C.H., Pezzin, S.H., Lugo Rivera, J.F., Bonato, P.S., Windmöller, C., Archundia, C., Collins, K.E., Liquid chromatographic separation of aqueous species of Cr(VI) and Cr(III) (1997) J. Chromatogr. A, 789, p. 469Collins, K.E., Bonato, P.S., Archundia, C., De Queiroz, M.E.L.R., Collins, C.H., Column chromatographic separation of chromium for Cr(VI) and several species of Cr(III) (1988) Chromatographia, 26, p. 160Autenrieth, W., Ueber einige chromsaure und dichromsaure salze (1902) Ber. Deutsch. Chem. Ges., 35, p. 2057(1985) Annual Book of ASTM Standards, Section 3, Vol.03.05, "Chemical Analysis of Metals and Metal-Bearing Ores", , American Society for Testing and Materials, PhiladelphiaOttaway, J.M., Fell, G.S., Determination of chromium in biological materials (1986) Pure Appl. Chem., 58, p. 170
Stability Studies Of Stationary Phases From Poly(methyltetradecylsiloxane) Sorbed And Immobilized Onto Metalized And Unmodified Silicas
No full textStationary phases for RP-HPLC were prepared from metalized (titanized and zirconized) and unmodified silica particles using sorbed and immobilized poly(methyltetradecylsiloxane) (PMTDS). Different immobilization procedures, such as gamma irradiation and thermal treatments, were used for the preparation of the immobilized PMTDS phases. The stabilities of these stationary phases were evaluated by passing alkaline (pH 10) mobile phase through 60 mm. × 3.9 mm columns of the different phases, with periodic tests to evaluate chromatographic performance. The results show that higher stabilities were obtained with stationary phases based on PMTDS immobilized on zirconized silica, these phases being 50% more stable than their titanized silica counterparts and 400% more stable than those based on unmodified silica. These supports provide higher chemical stability to the laboratory-made stationary phases, when compared with chemically bonded silica-based phases. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.301218441851Engelhardt, H., Blay, C., Saar, J., (2005) Chromatographia, 62, pp. S19-S29Claessens, H.A., van Straten, M.A., (2004) J. Chromatogr. A, 1060, pp. 23-41Nawrocki, J., Dunlap, C., Li, J., Zhao, J., McNeff, C.V., McCormick, A., Carr, P.W., (2004) J. Chromatogr. A, 1028, pp. 31-62Zhao, J., Carr, P.W., (1999) Anal. Chem, 71, pp. 5217-5224Li, J., Carr, P.W., (1997) Anal. Chem, 69, pp. 2193-2201Kirkland, J.J., Adams Jr., J.B., van Straten, M.A., Claessens, H.A., (1998) Anal. Chem, 70, pp. 4344-4352Kirkland, J.J., Glajch, J.L., Farlee, R.D., (1989) Anal. Chem, 61, pp. 2-11Ascah, T.L., Kallury, K.M.L., Szafranski, C.A., Corman, S.D., Lui, F., (1996) J. Liq. Chromatogr. Relat. Technol, 19, pp. 3049-3073O'Gara, J., Walsh, D., Phoebe, C., Alden, B., Bouvier, E., Iraneta, P., Capparella, M., Walter, T., (2001) LC-GC, 19, pp. 632-642Silva, C.R., Jardim, I.C.S.F., Airoldi, C., (2001) J. Chromatogr. A, 913, pp. 65-73Bien-Vogelsang, U., Deege, A., Figge, H., Köhler, J., Schomburg, G., (1984) Chromatographia, 19, pp. 170-179Petro, M., Berek, D., (1993) Chromatographia, 37, pp. 549-561Bottoli, C.B.G., Chaudhry, Z.F., Fonseca, D.A., Collins, K.E., Collins, C.H., (2002) J. Chromatogr. A, 948, pp. 121-128Lopes, N.P., Collins, K.E., Jardim, I.C.S.F., (2003) J. Chromatogr. A, 987, pp. 77-85Cheng, Y.F., Walter, T.H., Lu, Z., Iraneta, P., Alden, B.A., Genderau, C., Neue, U.D., Fisk, R.P., (2000) LC-GC, 18, pp. 1162-1172Wyndham, K.D., O'Gara, J.E., Walter, T.H., Glose, K.H., Lawrence, N.L., Alden, B.A., Izzo, G.S., Iraneta, P.C., (2003) Anal. Chem, 75, pp. 6781-6788Dun, H., Zhang, W., Wei, Y., Xiuquing, S., Li, Y., Chen, L., (2004) Anal. Chem, 76, pp. 5016-5023Faria, A.M., Magalhães, D.R., Collin, K.E., Collins, C.H., (2005) Anal. Chim. Acta, 550, pp. 137-143Faria, A.M., Jardim, I.C.S.F., Collins, K.E., Collins, C.H.J., (2006) Sep. Sci, 29, pp. 782-789Silva, C.R., Collins, C.H., Collins, K.E., Airoldi, C., (2006) J. Sep. Sci, 29, pp. 790-800Faria, A.M., Magalhães, D.R., Collins, C.H., (2004) Revista Matéria, 9, pp. 344-354Collins, K.E., Franchon, A.C., Jardim, I.C.S.F., Radanovic, E., Gonçalves, M.C., (2000) LC-GC, 18, pp. 106-117Fonseca, D.A., Gutiérrez, H.R., Collins, K.E., Collins, C.H., (2004) J. Chromatogr. A, 1030, pp. 149-155Faria, A.M., Collins, K.E., Collins, C.H., (2006) J. Chromatogr. A, 1122, pp. 114-122Faria, A.M., Collins, K.E., Collins, C.H., (2007) J. Chromatogr. A, , in pressSpinks, J.W.T., Woods, R.J., (1990) Introduction to Radiation Chemistry, , Wiley Interscience, New YorkCollins, K.E., Bottoli, C.B.G., Vigna, C.R.M., Bachmann, S., Albert, K., Collins, C.H., (2004) J. Chromatogr. A, 1029, pp. 43-4
Titanized Silica-based Stationary Phases Prepared With Thermally And Microwave-immobilized Poly(methyloctylsiloxane)
No full textSilica supports having their surface modified with titanium oxide were prepared and coated with poly(methyloctylsiloxane) (PMOS). Subsequently, immobilization of the polysiloxane was induced by thermal treatment or microwave radiation. The thermal treatment was carried out for different times (4, 8, 16 and 24h) at temperatures ranging between 100 and 220°C. For PMOS immobilization by microwave radiation, 452, 520 and 586W power levels and exposure times of 5, 15 and 30min were used. After extraction of non-immobilized polymer, the chromatographic properties of the phases were evaluated. The phase immobilized at 120°C for 8h presented the best chromatographic parameters, suggesting that the quantity of acidic hydroxyl groups on the support surface was reduced, resulting in fewer undesirable interactions of a basic solute with the silanols not removed or covered on the support surface. © 2003 Elsevier B.V. All rights reserved.10301-2209215R.E. Majors, (1997) Curr. Issues HPLC Technol., LC-GC15 (SUPPL.), pp. S8-519Majors, R.E., (2003) LC-GC, 21, p. 240Sholten, A.B., De Haan, J.W., Claessen, H.A., Van De Vem, L.J.M., Cramers, C.A., (1994) J. Chromatogr. A, 688, p. 25Kirkland, J.J., Glajch, J.L., Farlee, R.D., (1989) Anal. Chem., 61, p. 2Hetem, M.J.J., De Haan, J.W., Claessens, H.A., Van De Vem, L.J.M., Cramers, C.A., (1990) Anal. Chem., 62, p. 2288Mileer, N.T., Dibussolo, J.M., (1990) J. Chromatogr., 499, p. 317Wirth, M.J., Fatunmbi, H.O., (1993) Anal. Chem., 65, p. 822Fairbank, R.W.P., Wirth, M.J., (1999) J. Chromatogr. A, 830, p. 285Akapo, S.O., Fatunmbi, H., (1999) LC-GC, 17, p. 334Li, L., Carr, P.W., Evans, J.F., (2000) J. Chromatogr. A, 868, p. 153H. Engelhardt, H. Löw, W. Eberhardt, M. Mauss, (1989) Chromatographia, 27, p. 535Zuo, Y.M., Zhu, B.R., Liao, Y., Gui, M.D., Pang, Z.L., Qi, J.X., (1994) Chromatographia, 38, p. 756Hetem, M.J.J., De Haan, J.W., Claessens, H.A., Cramers, C.A., (1991) J. Chromatogr., 540, p. 53Bien-Vogelsang, U., Deege, A., Figge, H., Köhler, J., (1984) Chromatographia, 19, p. 170Nyholm, L.M., Markides, K.E., (1998) J. Chromatogr. A, 813, p. 11Schomburg, G., (1991) Trends Anal. Chem., 10, p. 163Jardim, I.C.S.F., Collins, K.E., Anazawa, T.A., (1999) J. Chromatogr. A, 849, p. 299Tonhi, E., Collins, K.E., Collins, C.H., (2002) J. Chromatogr. A, 948, p. 109Bottoli, C.B.G., Chaudhry, Z.F., Fonseca, D.A., Collins, K.E., Collins, C.H., (2002) J. Chromatogr. A, 948, p. 121Kurganov, A., Trüdinger, U., Isajeva, T., Unger, K., (1996) Chromatographia, 42, p. 217Trüdinger, U., Müller, G., Unger, K.K., (1990) J. Chromatogr., 535, p. 111Kawahara, M., Nakamura, H., Nakajima, T., (1990) J. Chromatogr., 515, p. 149Wirth, H.J., Erikson, K.O., Holt, P., Aguilar, M., Hearn, M.T.W., (1993) J. Chromatogr., 646, p. 129Winkler, J., Marmé, S.J., (2000) J. Chromatogr. A, 888, p. 51Yu, J.C., Qu, F., Lin, J., Lam, H., Chen, Z., (2001) J. Liq. Chromatogr. Relat. Technol., 24, p. 367Mcnelf, J.A., Carr, P.W., (1992) Anal. Chem., 67, p. 3886Hu, J., Carr, P.W., (1992) Anal. Chem., 70, p. 1934Yu, J., Rassi, Z.E., (1993) J. Chromatogr., 631, p. 91Tani, K., Suzuki, Y., (1996) J. Chromatogr. A, 722, p. 129Pesek, J.J., Matyska, M.T., Ramakishnan, J., (1997) Chromatographia, 44, p. 538Pursch, M., Vanderhart, D.L., Sander, L.C., Gu, L., Nguyen, T., Wise, S.A., Gajewski, D.D., (2000) J. Am. Chem. Soc., 122, p. 6997Melo, L.F.C., Jardim, S.F., (1999) J. Chromatogr. A, 845, p. 423Melo, L.F.C., Collins, C.H., Collins, K.E., Jardim, I.C.S.F., (2000) J. Chromatogr. A, 869, p. 129Silva, R.B., Collins, C.H., (1999) J. Chromatogr. A, 845, pp. 417-422Silva, R.B., Collins, K.E., Collins, C.H., (2000) J. Chromatogr. A, 869, p. 136Silva, R.B., Gushikem, Y., Collins, C.H., (2001) J. Sep. Sci., 24, p. 49Nawrocki, J., (1991) Chromatographia, 31, p. 193Collins, K.E., Franchon, A.C., Jardim, I.C.S.F., Radovanovic, E., Gonçalves, M.C., (2000) LC-GC, 18, p. 10
Influence Of The Tio2 Content On The Chromatographic Performance And High Ph Stability Of C18 Titanized Phases
No full textTo extend pH stability, protective metal oxide layers, such as titanium oxide, that are more stable in alkaline medium, can be chemically bonded to the chromatographic silica surface prior to reaction with silanes. In the present work, the influence of the titanium oxide content on the chromatographic performance was investigated by synthesizing a C18 phase onto a doubly-titanized silica support and comparing its chromatographic performance with a C18 phase on singly-titanized silica. The Engelhardt and Tanaka test mixtures were used for chromatographic characterizations using short HPLC columns. The column lifetimes of these titanized phases were also compared by performing accelerated aging tests at 50 °C using aggressive phosphate mobile phases at pH 10. © 2006 Elsevier B.V. All rights reserved.111414552Majors, R.E., (2003) LC-GC Europe, 16, p. 8Grumbach, E.S., Wheat, T.E., Kelly, M., Mazzeo, J.R., (2005) LC-GC Suppl., 5, p. 40Yang, X., Ma, L., Carr, P.W., (2005) J. Chromatogr. A, 1079, p. 213Kirkland, J.J., (2004) J. Chromatogr. A, 1060, p. 9Kirkland, J.J., Adams Jr., J.B., van Straten, M.A., Claessens, H.A., (1998) Anal. Chem., 70, p. 4344Wirth, M.J., Fairbank, R.W.P., Fatumbi, H.O., (1997) Science, 275, p. 44Trammel, B.C., Ma, L., Luo, H., Hillmyer, M.A., Carr, P.W., (2004) J. Chromatogr. A, 1060, p. 61Cheng, Y.F., Walter, T.H., Lu, Z., Iraneta, P., Alden, B.A., Genderau, C., Neue, U.D., Fisk, R.P., (2000) LC-GC, 18, p. 1162Wyndhan, K.D., O'Gara, J.E., Walter, T.H., Glose, K.H., Lawrence, N.L., Alden, B.A., Izzo, G.S., Iraneta, P.C., (2004) Anal. Chem., 75, p. 6781Pesek, J.J., Tang, V.H., (1994) Chromatographia, 649, p. 649Nawrocki, J., Dunlap, C., Li, J., Zhao, J., McNeff, C.V., McCormick, A., Carr, P.W., (2004) J. Chromatogr. A, 1028, p. 31Dum, H., Zhang, W., Wei, Y., Xiuqing, S., Li, Y., Chen, L., (2004) Anal. Chem., 76, p. 5016Ellwanger, A., Matyska, M.T., Albert, K., Pesek, J.J., (1999) Chromatographia, 49, p. 424Buchmeiser, R., (2001) J. Chromatogr. A, 918, p. 233Nawrocki, J., Dunlap, C., McCormick, A., Carr, P.W., (2004) J. Chromatogr. A, 1028, p. 1Claessens, H.A., van Straten, M.A., (2004) J. Chromatogr. A, 1060, p. 23Silva, R.B., Gushikem, Y., Collins, C.H., (2001) J. Sep. Sci., 869, p. 49Fonseca, D.A., Collins, K.E., Collins, C.H., (2004) J. Chromatogr. A, 1030, p. 209Morais, L.R.S., Jardim, I.C.S.F., (2005) J. Chromatogr. A, 1073, p. 127Faria, A.M., Magalhães, D.R., Collins, K.E., Collins, C.H., (2005) Anal. Chim. Acta, 550, p. 137Silva, C.R., Airoldi, C., Collins, K.E., Collins, C.H., (2004) LC-GC, 22, p. 632Silva, C.R., Airoldi, C., Collins, K.E., Collins, C.H., (2005) J. Chromatogr. A, 1073, p. 155Silva, C.R., Airoldi, C., Collins, K.E., Collins, C.H., (2005) J. Chromatogr. A, 1087, p. 29Stout, R.W., DeStefano, J.J., (1985) J. Chromatogr., 326, p. 63Kirkland, J.J., van Straten, M.A., Claessens, H.A., (1995) J. Chromatogr. A, 691, p. 3Engelhardt, H., Arangio, M., Lobert, T., (1997) LC-GC, 15, p. 856Kimata, K., Iwaguchi, K., Onishi, S., Jinno, K., Eksteen, R., Hosoya, K., Araki, M., Tanaka, N., (1989) J. Chromatogr. Sci., 27, p. 721Fonseca, D.A., Gutierrez, H.R., Collins, K.E., Collins, C.H., (2004) J. Chromatogr. A, 1030, p. 149Berendsen, G.E., Pikaart, K.A., de Galan, L., (1980) J. Liq. Chromatogr., 3, p. 1437Albert, K., (2003) J. Sep. Sci., 215, p. 215Bachmann, S., Melo, L.F.C., Silva, R.B., Anazawa, T.A., Jardim, I.C.S.F., Collins, K.E., Collins, C.H., Albert, K., (2001) Chem. Mater., 13, p. 1874Engelhardt, H., Grüner, R., Scherer, M., (2001) Chromatographia, 53, pp. S154Murayama, K., Nakamura, H., Takahashi, K., Yoshida, A., (1994) Anal. Sci., 10, p. 815Kurganov, A., Trudinger, U., Isaeva, T., Unger, K., (1996) Chromatographia, 42, p. 217Euerby, M.R., Petersson, P., (2000) LC-GC Europe, 13, p. 665Sander, L.C., Wise, S.A., (1995) Anal. Chem., 67, p. 3284McDonald, P.D., (2003) Advances in Chromatography, p. 324. , Brown P.R., and Gruska E. (Eds), Marcel Dekker, New YorkEuerby, M.R., Petersson, P., (2003) J. Chromatogr. A, 994, p. 1
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