The Experts below are selected from a list of 510 Experts worldwide ranked by ideXlab platform

Pezza, Helena Redigolo - One of the best experts on this subject based on the ideXlab platform.

  • Spectrophotometric determination of hexamethylenetetramine (HMT) in pharmaceutical preparations using Chromotropic Acid and microwave oven
    'FapUNIFESP (SciELO)', 2015
    Co-Authors: Fagnani Enelton, Pezza Leonardo, Pezza, Helena Redigolo
    Abstract:

    This paper proposes a methodology for spectrophotometric determination of hexamethylenetetramine (HMT) by using Chromotropic Acid in a phosphoric Acid media employing a domestic microwave oven as a source of heating. The reddish-purple soluble product is quantitatively formed after 30 s of irradiation and obeys the Beer´s law in the range between 0.1-1.2 mg L-1 HMT (r = 0.99925). The method was applied successfully in commercial pharmaceutical preparations containing dyes in their composition. The results showed that the method proposed is feasible for simplicity, speed, low cost, precision and accuracy when compared with United States Pharmacopeia official method.24582463Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

  • Determinação espectrofotométrica de hexametilenotetramina (HMT) em medicamentos, utilizando ácido cromotrópico e forno de micro-ondas
    Sociedade Brasileira de Química, 2009
    Co-Authors: Pezza, Helena Redigolo
    Abstract:

    This paper proposes a methodology for spectrophotometric determination of hexamethylenetetramine (HMT) by using Chromotropic Acid in a phosphoric Acid media employing a domestic microwave oven as a source of heating. The reddish-purple soluble product is quantitatively formed after 30 s of irradiation and obeys the Beer´s law in the range between 0.1-1.2 mg L-1 HMT (r = 0.99925). The method was applied successfully in commercial pharmaceutical preparations containing dyes in their composition. The results showed that the method proposed is feasible for simplicity, speed, low cost, precision and accuracy when compared with United States Pharmacopeia official method

  • Determinação espectrofotométrica de hexametilenotetramina (HMT) em medicamentos, utilizando ácido cromotrópico e forno de micro-ondas
    Sociedade Brasileira de Química, 2009
    Co-Authors: Fagnani Enelton, Pezza Leonardo, Pezza, Helena Redigolo
    Abstract:

    This paper proposes a methodology for spectrophotometric determination of hexamethylenetetramine (HMT) by using Chromotropic Acid in a phosphoric Acid media employing a domestic microwave oven as a source of heating. The reddish-purple soluble product is quantitatively formed after 30 s of irradiation and obeys the Beer´s law in the range between 0.1-1.2 mg L-1 HMT (r = 0.99925). The method was applied successfully in commercial pharmaceutical preparations containing dyes in their composition. The results showed that the method proposed is feasible for simplicity, speed, low cost, precision and accuracy when compared with United States Pharmacopeia official method.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

  • A Simple and Green Analytical Method for the Determination of Formaldehyde
    Soc Brasileira Quimica, 2008
    Co-Authors: Gasparini Fabricia, Pezza Leonardo, Weinert,patrícia L., Lima,liliane S., Pezza, Helena Redigolo
    Abstract:

    A green spectrophotometric analytical method for determination of formaldehyde in commercial samples was designed and investigated. Replacement of hazardous reagents was explored to attain the clean chemistry standards. The method is based on formaldehyde reaction with Chromotropic Acid in the presence of magnesium sulphate producing a stable complex Mg(2+)/cyclotetrachromotropylene (lambda(max) = 535 nm). To the best of our knowledge, there are no reports on the use of the above mentioned reaction for this determination. The experimental conditions were optimized by the response surface methodologies. Beer's Law is obeyed in a concentration range of 3 to 11 mg L(-1) of formaldehyde with a correlation coefficient of 0.999. The proposed method was applied for the determination of formaldehyde in commercial disinfectants and deffrizing hair products. The results were favorably compared with those of the official method, with good accuracy and precision.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

  • Spectrophotometric determination of formaldehyde with Chromotropic Acid in phosphoric Acid medium assisted by microwave oven
    Elsevier B.V., 2004
    Co-Authors: Gigante A. C., Gotardo M. A., Tognolli J. O., Pezza Leonardo, Pezza, Helena Redigolo
    Abstract:

    In the present study. a spectrophotometric method for the determination of formaldehyde by using Chromotropic Acid was devised. in which the use of potentially hazardous and corrosive concentrated sulfuric Acid was eliminated and advantageously C replaced by a mixture of H, concentrated H3PO4 and H2O2. The reaction between formaldehyde and Chromotropic Acid (CA) in a cone phosphoric Acid medium was accelerate by irradiating the mixture with microwave energy for 35 s (1100 W), producing a violetred compound (lambda(max)=570 nm). Beer's Law is obeyed in a concentration range of 0.8-4.8 mg 1(-1) of formaldehyde with a good correlation coefficient (r = 0.9968). The proposed method was applied in the analysis of formaldehyde in commercial disinfectants. Recoveries were within 98.0-100.4%, with standard deviations ranging from 0.03 to 0.13%. (C) 2003 Elsevier B.V All rights reserved

Fagnani Enelton - One of the best experts on this subject based on the ideXlab platform.

  • Spectrophotometric determination of hexamethylenetetramine (HMT) in pharmaceutical preparations using Chromotropic Acid and microwave oven
    'FapUNIFESP (SciELO)', 2015
    Co-Authors: Fagnani Enelton, Pezza Leonardo, Pezza, Helena Redigolo
    Abstract:

    This paper proposes a methodology for spectrophotometric determination of hexamethylenetetramine (HMT) by using Chromotropic Acid in a phosphoric Acid media employing a domestic microwave oven as a source of heating. The reddish-purple soluble product is quantitatively formed after 30 s of irradiation and obeys the Beer´s law in the range between 0.1-1.2 mg L-1 HMT (r = 0.99925). The method was applied successfully in commercial pharmaceutical preparations containing dyes in their composition. The results showed that the method proposed is feasible for simplicity, speed, low cost, precision and accuracy when compared with United States Pharmacopeia official method.24582463Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

  • Spectrophotometric determination of hexamethylenetetramine (HMT) in pharmaceutical preparations using Chromotropic Acid and microwave oven
    Sociedade Brasileira de Química, 2009
    Co-Authors: Fagnani Enelton, Pezza, Leonardo [unesp], Pezza, Helena Redigolo [unesp]
    Abstract:

    This paper proposes a methodology for spectrophotometric determination of hexamethylenetetramine (HMT) by using Chromotropic Acid in a phosphoric Acid media employing a domestic microwave oven as a source of heating. The reddish-purple soluble product is quantitatively formed after 30 s of irradiation and obeys the Beer´s law in the range between 0.1-1.2 mg L-1 HMT (r = 0.99925). The method was applied successfully in commercial pharmaceutical preparations containing dyes in their composition. The results showed that the method proposed is feasible for simplicity, speed, low cost, precision and accuracy when compared with United States Pharmacopeia official method

  • Determinação espectrofotométrica de hexametilenotetramina (HMT) em medicamentos, utilizando ácido cromotrópico e forno de micro-ondas
    Sociedade Brasileira de Química, 2009
    Co-Authors: Fagnani Enelton, Pezza Leonardo, Pezza, Helena Redigolo
    Abstract:

    This paper proposes a methodology for spectrophotometric determination of hexamethylenetetramine (HMT) by using Chromotropic Acid in a phosphoric Acid media employing a domestic microwave oven as a source of heating. The reddish-purple soluble product is quantitatively formed after 30 s of irradiation and obeys the Beer´s law in the range between 0.1-1.2 mg L-1 HMT (r = 0.99925). The method was applied successfully in commercial pharmaceutical preparations containing dyes in their composition. The results showed that the method proposed is feasible for simplicity, speed, low cost, precision and accuracy when compared with United States Pharmacopeia official method.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

  • Desenvolvimento de método espectrofotométrico para análise de paraformaldeído em saneantes comerciais e industriais
    Editora Unesp, 2002
    Co-Authors: Fagnani Enelton, Pezza Leonardo, Melios, Cristo Bladimiros, Pezza, Helena Redigolo
    Abstract:

    O presente artigo descreve uma metodologia espectrofotométrica para a análise de paraformaldeído presente em amostras de saneantes comerciais e industriais, utilizando-se ácido cromotrópico (ACT), ácido clorídrico concentrado e peróxido de hidrogênio, produzindo um composto púrpura - avermelhado (lambda max = 575 nm). A lei de Beer é obedecida numa faixa de concentração de 0,8 - 4,8 mg L-1 em formaldeído, apresentando excelente coeficiente de correlação (r = 0,9999). Os valores obtidos nas análises concordaram muito favoravelmente com os obtidos pelo procedimento padrão recomendado pelo NIOSH (National Institute for Occupational Safety and Health).This paper describes a spectrophotometric method for the paraformaldehyde analysis in industrial and commercial disinfectant samples using Chromotropic Acid, concentrated hydrochloridric Acid and hydrogen peroxide. The reaction produces a violet-red compound (lambda max = 575 nm). The method permits the determination of paraformaldehyde over a concentration range of 0.8-4.8 mg L-1 and the results obtained by the proposed method compared very favorably with those obtained by NIOSH s standard procedure.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Pezza Leonardo - One of the best experts on this subject based on the ideXlab platform.

  • Spectrophotometric determination of hexamethylenetetramine (HMT) in pharmaceutical preparations using Chromotropic Acid and microwave oven
    'FapUNIFESP (SciELO)', 2015
    Co-Authors: Fagnani Enelton, Pezza Leonardo, Pezza, Helena Redigolo
    Abstract:

    This paper proposes a methodology for spectrophotometric determination of hexamethylenetetramine (HMT) by using Chromotropic Acid in a phosphoric Acid media employing a domestic microwave oven as a source of heating. The reddish-purple soluble product is quantitatively formed after 30 s of irradiation and obeys the Beer´s law in the range between 0.1-1.2 mg L-1 HMT (r = 0.99925). The method was applied successfully in commercial pharmaceutical preparations containing dyes in their composition. The results showed that the method proposed is feasible for simplicity, speed, low cost, precision and accuracy when compared with United States Pharmacopeia official method.24582463Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

  • Determinação espectrofotométrica de hexametilenotetramina (HMT) em medicamentos, utilizando ácido cromotrópico e forno de micro-ondas
    Sociedade Brasileira de Química, 2009
    Co-Authors: Fagnani Enelton, Pezza Leonardo, Pezza, Helena Redigolo
    Abstract:

    This paper proposes a methodology for spectrophotometric determination of hexamethylenetetramine (HMT) by using Chromotropic Acid in a phosphoric Acid media employing a domestic microwave oven as a source of heating. The reddish-purple soluble product is quantitatively formed after 30 s of irradiation and obeys the Beer´s law in the range between 0.1-1.2 mg L-1 HMT (r = 0.99925). The method was applied successfully in commercial pharmaceutical preparations containing dyes in their composition. The results showed that the method proposed is feasible for simplicity, speed, low cost, precision and accuracy when compared with United States Pharmacopeia official method.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

  • A Simple and Green Analytical Method for the Determination of Formaldehyde
    Soc Brasileira Quimica, 2008
    Co-Authors: Gasparini Fabricia, Pezza Leonardo, Weinert,patrícia L., Lima,liliane S., Pezza, Helena Redigolo
    Abstract:

    A green spectrophotometric analytical method for determination of formaldehyde in commercial samples was designed and investigated. Replacement of hazardous reagents was explored to attain the clean chemistry standards. The method is based on formaldehyde reaction with Chromotropic Acid in the presence of magnesium sulphate producing a stable complex Mg(2+)/cyclotetrachromotropylene (lambda(max) = 535 nm). To the best of our knowledge, there are no reports on the use of the above mentioned reaction for this determination. The experimental conditions were optimized by the response surface methodologies. Beer's Law is obeyed in a concentration range of 3 to 11 mg L(-1) of formaldehyde with a correlation coefficient of 0.999. The proposed method was applied for the determination of formaldehyde in commercial disinfectants and deffrizing hair products. The results were favorably compared with those of the official method, with good accuracy and precision.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

  • Spectrophotometric determination of formaldehyde with Chromotropic Acid in phosphoric Acid medium assisted by microwave oven
    Elsevier B.V., 2004
    Co-Authors: Gigante A. C., Gotardo M. A., Tognolli J. O., Pezza Leonardo, Pezza, Helena Redigolo
    Abstract:

    In the present study. a spectrophotometric method for the determination of formaldehyde by using Chromotropic Acid was devised. in which the use of potentially hazardous and corrosive concentrated sulfuric Acid was eliminated and advantageously C replaced by a mixture of H, concentrated H3PO4 and H2O2. The reaction between formaldehyde and Chromotropic Acid (CA) in a cone phosphoric Acid medium was accelerate by irradiating the mixture with microwave energy for 35 s (1100 W), producing a violetred compound (lambda(max)=570 nm). Beer's Law is obeyed in a concentration range of 0.8-4.8 mg 1(-1) of formaldehyde with a good correlation coefficient (r = 0.9968). The proposed method was applied in the analysis of formaldehyde in commercial disinfectants. Recoveries were within 98.0-100.4%, with standard deviations ranging from 0.03 to 0.13%. (C) 2003 Elsevier B.V All rights reserved

  • Chromotropic Acid-formaldehyde reaction in strongly Acidic media. The role of dissolved oxygen and replacement of concentrated sulphuric Acid
    Elsevier B.V., 2003
    Co-Authors: Fagnani E., Pezza Leonardo, Melios C. B., Pezza, Helena Redigolo
    Abstract:

    The procedure for formaldehyde analysis recommended by the National Institute for Occupational Safety and Health (NIOSH) is the Chromotropic Acid spectrophotometric method, which is the one that uses concentrated sulphuric Acid. In the present study the oxidation step associated with the aforementioned method for formaldehyde determination was investigated. Experimental evidence has been obtained indicating that when concentrated H2SO4 (18 mol l(-1)) is used (as in the NIOSH procedure) that Acid is the oxidizing agent. on the other hand, oxidation through dissolved oxygen takes place when concentrated H2SO4 is replaced by concentrated hydrochloric (12 mol l(-1)) and phosphoric (14.7 mol l(-1)) Acids as well as by diluted H2SO4 (9.4 mol l(-1)). Based on investigations concerning the oxidation step, a modified procedure was devised, in which the use of the potentially hazardous and corrosive concentrated H2SO4 was eliminated and advantageously replaced by a less harmful mixture of HCl and H2O2. (C) 2003 Elsevier B.V. B.V. All rights reserved

Pezza H.r. - One of the best experts on this subject based on the ideXlab platform.

  • Spectrophotometric Determination Of Hexamethylenetetramine (hmt) In Pharmaceutical Preparations Using Chromotropic Acid And Microwave Oven [determinação Espectrofotométrica De Hexametilenotetramina (hmt) Em Medicamentos, Utilizando ácido Cromotrópico E Forno De Micro-ondas]
    2015
    Co-Authors: Fagnani E., Pezza L., Pezza H.r.
    Abstract:

    This paper proposes a methodology for spectrophotometric determination of hexamethylenetetramine (HMT) by using Chromotropic Acid in a phosphoric Acid media employing a domestic microwave oven as a source of heating. The reddish-purple soluble product is quantitatively formed after 30 s of irradiation and obeys the Beeŕs law in the range between 0.1-1.2 mg L-1 HMT (r = 0.99925). The method was applied successfully in commercial pharmaceutical preparations containing dyes in their composition. The results showed that the method proposed is feasible for simplicity, speed, low cost, precision and accuracy when compared with United States Pharmacopeia official method

  • Spectrophotometric Determination Of Hexamethylenetetramine (hmt) In Pharmaceutical Preparations Using Chromotropic Acid And Microwave Oven [determinação Espectrofotométrica De Hexametilenotetramina (hmt) Em Medicamentos, Utilizando ácido Cromotrópico E Forno De Micro-ondas]
    2015
    Co-Authors: Fagnani E., Pezza L., Pezza H.r.
    Abstract:

    This paper proposes a methodology for spectrophotometric determination of hexamethylenetetramine (HMT) by using Chromotropic Acid in a phosphoric Acid media employing a domestic microwave oven as a source of heating. The reddish-purple soluble product is quantitatively formed after 30 s of irradiation and obeys the Beeŕs law in the range between 0.1-1.2 mg L-1 HMT (r = 0.99925). The method was applied successfully in commercial pharmaceutical preparations containing dyes in their composition. The results showed that the method proposed is feasible for simplicity, speed, low cost, precision and accuracy when compared with United States Pharmacopeia official method.32924582463Nickel, J.C., (2005) J. Urol., 173, p. 21Kaszycki, P., Koloczek, H., (2002) Biodegradation, 13, p. 91Kirk, R.E., Othmer, D.F., Encyclopedia of chemical technology (1951) The Interscience Encyclopedia, , New YorkSharma, S.P., Lahiri, S.C., (2008) J. Indian Chem. Soc., 85, p. 273Turi, E.A., (1981) Thermal Caracterization of Polymeric Materials, , Academic Press: OrlandoMadsen, G.L., Jaselkis, B., (1992) Analyst, 117, p. 1785Tomcik, P., Mrafkova, L., Bustin, D., (2003) Microchim. Acta, 141, p. 69Dzyadevych, S.V., Arkhypova, V.N., Korpan, Y.I., El'skaya, A.V., Soldatkin, A.P., Jaffrezic-Renault, N., Martelet, C., (2001) Anal. Chim. Acta, 445, p. 47Korpan, Y.I., Gonchar, M.V., Sibirny, A.A., Martelet, C., El'skaya, A.V., Gibson, T.D., Soldatkin, A.P., (2000) Biosens. Bioelectron., 15, p. 77Burini, G., Coli, R., (2004) Anal. Chim. Acta, 511, p. 155Pérez-Ruiz, T., Martínez-Lozano, C., Fenoll, T.V., (2003) J. Anal. Bioanal. Chem., 375, p. 661Pinheiro, H.L.C., Andrade, V., Pereira, P.A.P., Andrade, J.B., (2004) Microchem. J., 78Reche, F., Garrigós, M.C., Sánchez, A., Jiménez, A., (2000) J. Chromatogr., A, 896, p. 51Kato, S., Burke, P.J., Fenick, D.J., Taatjes, D.J., Bierbaum, V.M., Koch, T.H., (2000) Chem. Res. Toxicol., 13, p. 509Kato, S., Burke, P.J., Koch, T.H., Bierbaum, V.M., (2001) Anal. Chem., 73Rivero, R.T., Topiwala, V., (2004) J. Chromatogr., A, 1029, p. 217http://www.cdc.gov/niosh/nmam/pdfs/3500.pdf, acessada em Setembro 2009Bosque-Sendra, J.M., Pescarolo, S., Cuadros-Rodríguez, L., García-Campaña, A.M., Almansa-López, E.M., (2001) Freseniuś J. Anal. Chem., 369, p. 715Ross, P.F., Draayer, H., Itoh, O., (2002) Biologicals, 30, p. 37Zhang, Z.Q., Yan, H.T., Yuc, X.F., (2004) Microchim. Acta, 146, p. 259Sibirny, V.A., Gonchar, M.V., Grabek-Lejko, D., Pavlishko, H.M., Csoregi, E., Sibirny, A.A., (2008) Int. J. Environ. Anal. Chem., 88, p. 289Feigl, F., (1956) Spot Tests in Organic Analysis, , 5th ed. Elsevier: AmsterdamGeorghiou, P.E., Ho, C.K., (1989) Can. J. Chem., 67Fagnani, E., Melios, C.B., Pezza, L., Pezza, H.R., (2003) Talanta, 60, p. 171Gigante, A.C., Gotardo, M.A., Tognolli, J.O., Pezza, L., Pezza, H.R., (2004) Microchem. J., 77, p. 47Tininis, A.G., Santini, A.O., Fagnani, E., Melios, C.B., Pezza, L., Pezza, H.R., (2001) Eclet. Quim., 26, p. 175Kingston, H.M., Jassie, L.B., (1988) Introduction to Microwave Sample Preparation - Theory and Practice, , ACS Professional Reference Books: WashingtonGigante, A.C., Pezza, L., Pezza, H.R., (2002) Eclet. Quim., 27, p. 223http://www.anvisa.gov.br/monitora/cmed/legis/comunicados/ lista_conformidade.pdf, acessada em Setembro 2009(1995) The United States Pharmacopeia - The National Formulary, , United States Pharmacopeial Convention, 23rd ed. U.S. Pharmacopeia: RockvilleMiller, J.N., Miller, J.C., (2000) Statistics and Chemometrics for Analytical Chemistry, , 4th ed. Pearson Education: EssexBalasubramanian, M., Thennarassu, S., Sudhakaran, T., Perumal, P.T., (2003) Biol. Pharm. Bull., 26, p. 1211Pavitrapok, C., Williams, D.A., (2006) J. Pharm. Biomed. Anal., 40, p. 1243(2000) Data Analysis and Technical Graphics, , OriginLab CorporationORIGIN® 6.1, Northampton, Estados Unido

Ralph P Tatam - One of the best experts on this subject based on the ideXlab platform.

  • fabrication and optimisation of a fused filament 3d printed microfluidic platform
    Journal of Micromechanics and Microengineering, 2017
    Co-Authors: A. M. Tothill, S.w. James, M Partridge, Ralph P Tatam
    Abstract:

    A 3D-printed microfluidic device was designed and manufactured using a low cost ($2,000) consumer grade fusion deposition modelling (FDM) 3D printer. Fusion deposition modelling (FDM) printers are not typically used, or are capable, of producing the fine detailed structures required for microfluidic fabrication. However, in this work, the optical transparency of the device was improved through manufacture optimisation to such a point that optical colorimetric assays can be performed in a 50 ��l device. A colorimetric enzymatic cascade assay was optimised using glucose oxidase and horseradish peroxidase for the oxidative coupling of aminoantipyrine and Chromotropic Acid to produce a blue quinoneimine dye with a broad absorbance peaking at 590 nm for the quantification of glucose in solution. For comparison the assay was run in standard 96 well plates with a commercial plate reader. The results show the accurate and reproducible quantification of 0-10 mM glucose solution using a 3D-printed microfluidic optical device with performance comparable to a plate reader assay.

  • Fabrication and optimisation of a fused filament 3D-printed microfluidic platform
    Journal of Micromechanics and Microengineering, 2017
    Co-Authors: A. M. Tothill, S.w. James, M Partridge, Ralph P Tatam
    Abstract:

    A 3D-printed microfluidic device was designed and manufactured using a low cost ($2000) consumer grade fusion deposition modelling (FDM) 3D printer. FDM printers are not typically used, or are capable, of producing the fine detailed structures required for microfluidic fabrication. However, in this work, the optical transparency of the device was improved through manufacture optimisation to such a point that optical colorimetric assays can be performed in a 50 μl device. A colorimetric enzymatic cascade assay was optimised using glucose oxidase and horseradish peroxidase for the oxidative coupling of aminoantipyrine and Chromotropic Acid to produce a blue quinoneimine dye with a broad absorbance peaking at 590 nm for the quantification of glucose in solution. For comparison the assay was run in standard 96 well plates with a commercial plate reader. The results show the accurate and reproducible quantification of 0–10 mM glucose solution using a 3D-printed microfluidic optical device with performance comparable to that of a plate reader assay.