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M. Conceição B. S. M. Montenegro - One of the best experts on this subject based on the ideXlab platform.
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Construction and evaluation of PVC and sol–gel sensor membranes based on Mn(III)TPP-Cl. Application to valproate determination in pharmaceutical preparations
Analytical and Bioanalytical Chemistry, 2006Co-Authors: Emilia M G Santos, Cristina M C M Couto, Alberto N Araujo, M. Conceição B. S. M. MontenegroAbstract:The construction and general performance of new valproate-selective electrodes based on manganese(III) tetraphenylporphyrin [Mn(III)TPP-Cl], as an ionophore, are presented. The ionophore was incorporated into PVC and ceramic membranes (sol–gel) based on methyltriethoxysilane. The influence of membrane composition and pH and the effect of lipophilic cationic and anionic additives in PVC membranes were investigated concerning their influence on the Slope, Response time, selectivity and lifetime of the electrodes. The PVC membrane without additive and the sol–gel membrane presented Slopes and practical limits of detection of −60.8 mV dec^−1 and 5x10^−6 mol l^−1 and −60.3 mV dec^−1 and 1×10^−4 mol l^−1, respectively. The sol–gel membranes displayed higher selectivity for valproate when compared with PVC membranes. These two types of electrodes were coupled to a sequential-injection analysis (SIA) system for the direct determination of valproate in pharmaceutical formulations. The association of Mn(III)TPP-Cl with the sol–gel support inserted in a SIA system provided potentiometric sensors with an analytical range of 1x10^−3–5x10^−2 mol l^−1, with a sample rate of 55 samples per hour and a sample and carrier consumption of 140 and 2,500 μl per determination, respectively.
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Construction and evaluation of PVC and sol-gel sensor membranes based on Mn(III)TPP-Cl. Application to valproate determination in pharmaceutical preparations.
Analytical and Bioanalytical Chemistry, 2005Co-Authors: Emilia M G Santos, Cristina M C M Couto, Alberto N Araujo, M. Conceição B. S. M. MontenegroAbstract:The construction and general performance of new valproate-selective electrodes based on manganese(III) tetraphenylporphyrin [Mn(III)TPP-Cl], as an ionophore, are presented. The ionophore was incorporated into PVC and ceramic membranes (sol–gel) based on methyltriethoxysilane. The influence of membrane composition and pH and the effect of lipophilic cationic and anionic additives in PVC membranes were investigated concerning their influence on the Slope, Response time, selectivity and lifetime of the electrodes. The PVC membrane without additive and the sol–gel membrane presented Slopes and practical limits of detection of −60.8 mV dec−1 and 5x10−6 mol l−1 and −60.3 mV dec−1 and 1×10−4 mol l−1, respectively. The sol–gel membranes displayed higher selectivity for valproate when compared with PVC membranes. These two types of electrodes were coupled to a sequential-injection analysis (SIA) system for the direct determination of valproate in pharmaceutical formulations. The association of Mn(III)TPP-Cl with the sol–gel support inserted in a SIA system provided potentiometric sensors with an analytical range of 1x10−3–5x10−2 mol l−1, with a sample rate of 55 samples per hour and a sample and carrier consumption of 140 and 2,500 μl per determination, respectively.
Emilia M G Santos - One of the best experts on this subject based on the ideXlab platform.
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Construction and evaluation of PVC and sol–gel sensor membranes based on Mn(III)TPP-Cl. Application to valproate determination in pharmaceutical preparations
Analytical and Bioanalytical Chemistry, 2006Co-Authors: Emilia M G Santos, Cristina M C M Couto, Alberto N Araujo, M. Conceição B. S. M. MontenegroAbstract:The construction and general performance of new valproate-selective electrodes based on manganese(III) tetraphenylporphyrin [Mn(III)TPP-Cl], as an ionophore, are presented. The ionophore was incorporated into PVC and ceramic membranes (sol–gel) based on methyltriethoxysilane. The influence of membrane composition and pH and the effect of lipophilic cationic and anionic additives in PVC membranes were investigated concerning their influence on the Slope, Response time, selectivity and lifetime of the electrodes. The PVC membrane without additive and the sol–gel membrane presented Slopes and practical limits of detection of −60.8 mV dec^−1 and 5x10^−6 mol l^−1 and −60.3 mV dec^−1 and 1×10^−4 mol l^−1, respectively. The sol–gel membranes displayed higher selectivity for valproate when compared with PVC membranes. These two types of electrodes were coupled to a sequential-injection analysis (SIA) system for the direct determination of valproate in pharmaceutical formulations. The association of Mn(III)TPP-Cl with the sol–gel support inserted in a SIA system provided potentiometric sensors with an analytical range of 1x10^−3–5x10^−2 mol l^−1, with a sample rate of 55 samples per hour and a sample and carrier consumption of 140 and 2,500 μl per determination, respectively.
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Construction and evaluation of PVC and sol-gel sensor membranes based on Mn(III)TPP-Cl. Application to valproate determination in pharmaceutical preparations.
Analytical and Bioanalytical Chemistry, 2005Co-Authors: Emilia M G Santos, Cristina M C M Couto, Alberto N Araujo, M. Conceição B. S. M. MontenegroAbstract:The construction and general performance of new valproate-selective electrodes based on manganese(III) tetraphenylporphyrin [Mn(III)TPP-Cl], as an ionophore, are presented. The ionophore was incorporated into PVC and ceramic membranes (sol–gel) based on methyltriethoxysilane. The influence of membrane composition and pH and the effect of lipophilic cationic and anionic additives in PVC membranes were investigated concerning their influence on the Slope, Response time, selectivity and lifetime of the electrodes. The PVC membrane without additive and the sol–gel membrane presented Slopes and practical limits of detection of −60.8 mV dec−1 and 5x10−6 mol l−1 and −60.3 mV dec−1 and 1×10−4 mol l−1, respectively. The sol–gel membranes displayed higher selectivity for valproate when compared with PVC membranes. These two types of electrodes were coupled to a sequential-injection analysis (SIA) system for the direct determination of valproate in pharmaceutical formulations. The association of Mn(III)TPP-Cl with the sol–gel support inserted in a SIA system provided potentiometric sensors with an analytical range of 1x10−3–5x10−2 mol l−1, with a sample rate of 55 samples per hour and a sample and carrier consumption of 140 and 2,500 μl per determination, respectively.
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determination of gibberellic acid by sequential injection analysis using a potentiometric detector based on mn iii porphyrin with improved characteristics
Journal of the Brazilian Chemical Society, 2004Co-Authors: Emilia M G Santos, Cristina M C M Couto, Alberto N Araujo, Conceicao M B S M Montenegro, Boaventura F ReisAbstract:This work describes the determination of gibberellic acid in growth promoters formulations used in agriculture by sequential injection analysis and potentiometric detection. The potentiometric detectors with improved characteristics used a PVC membrane prepared with Mn(III)tetraphenylporphyrin-Cl as electroactive specie. Different membranes formulated with several ionic additives were compared in order to select the most suitable one concerning Slope, Response time, reproducibility and selectivity. A membrane containing 6 wt% of manganese tetraphenylporphyrin-Cl [(Mn(TPP)Cl], 27 wt% of PVC, 66 wt% of dibutylphthalate (DBP), as mediator solvent, and 1 wt% of sodium tetraphenylborate, as anionic additive, was chosen for analytical applications. When coupled to a SIA system the tubular electrode presented a linear range between 5×10-4 mol L-1 and 8×10-3 mol L-1, a Slope of -64.5 ± 1.6 mV/dec and lower potentiometric selectivity coefficients (log Kpot) than those obtained with the conventional electrodes. Standard deviation of 0.01 and 0.4 (n= 4) and a sampling rate of 30 samples/hour were obtained in the analysis of real samples.
Petros Maragos - One of the best experts on this subject based on the ideXlab platform.
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Slope transforms: theory and application to nonlinear signal processing
IEEE Transactions on Signal Processing, 1995Co-Authors: Petros MaragosAbstract:Fourier transforms are among the most useful linear signal transformations for quantifying the frequency content of signals and for analyzing their processing by linear time-invariant systems. Some nonlinear signal transforms are developed that can provide information about the Slope content of signals and are useful analytic tools for large classes of nonlinear systems. Many of their theoretical properties are examined, showing a striking conceptual resemblance to Fourier transforms and their application to linear systems. These novel transforms, called Slope transforms, are originally derived from the eigenvalues of morphological dilation and erosion systems, where the corresponding eigenfunctions are lines /spl alpha/t+b parameterized by their Slope /spl alpha/. They obey a nonlinear superposition principle of the supremum- or infimum-of-sums type. Applied to the impulse Response of dilation or erosion systems, the Slope transforms provide a Slope Response function for these systems, which allows their analysis and design in a transform domain, the Slope domain. Applied to arbitrary signals, the Slope transforms provide information about upper or lower tangents to the signal's graph at varying Slopes. The upper or lower envelopes of the signal can be obtained from the inverse transforms. Overall, the Slope transforms provide a new transform domain for signals and morphological systems where time lines become Slope impulses, time cones become Slope bandpass filters, and time dilation/erosion transform into addition of Slope transforms. Their application to the design of Slope-selective filters is also presented.
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ISMM - Morphological Systems Theory: Slope Transforms, Max—Min Differential Equations, Envelope Filters, and Sampling
Computational Imaging and Vision, 1994Co-Authors: Petros MaragosAbstract:In this paper we view the basic morphological signal operators as a class of nonlinear systems obeying a supremum/infimum-of-sums superposition and endow them with analytic tools that parallel the functionality of and have many conceptual similarities with ideas and tools used in linear systems. In the time/space domain, these systems are found equivalent to a max-plus or min-plus convolution with their impulse Response, and a class of nonlinear difference/differential equations is introduced to describe their dynamics The hyperplanes +b are eigenfunctions of such morphological systems, which leads to developing a Slope Response for them, as a function of the Slope α, and related Slope transforms for arbitrary signals. These ideas provide a transform (Slope) domain for morphological systems, where dilation and erosion in time/space corresponds to addition of Slope transforms, time/space hyperplanes transform into Slope impulses, time/space cones become bandpass Slope-selective filters, and distance transforms correspond to ideal Slope filters. The paper summarizes results for 1D signals/systems and extends them to the 2D case and to sampling.
Cristina M C M Couto - One of the best experts on this subject based on the ideXlab platform.
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Construction and evaluation of PVC and sol–gel sensor membranes based on Mn(III)TPP-Cl. Application to valproate determination in pharmaceutical preparations
Analytical and Bioanalytical Chemistry, 2006Co-Authors: Emilia M G Santos, Cristina M C M Couto, Alberto N Araujo, M. Conceição B. S. M. MontenegroAbstract:The construction and general performance of new valproate-selective electrodes based on manganese(III) tetraphenylporphyrin [Mn(III)TPP-Cl], as an ionophore, are presented. The ionophore was incorporated into PVC and ceramic membranes (sol–gel) based on methyltriethoxysilane. The influence of membrane composition and pH and the effect of lipophilic cationic and anionic additives in PVC membranes were investigated concerning their influence on the Slope, Response time, selectivity and lifetime of the electrodes. The PVC membrane without additive and the sol–gel membrane presented Slopes and practical limits of detection of −60.8 mV dec^−1 and 5x10^−6 mol l^−1 and −60.3 mV dec^−1 and 1×10^−4 mol l^−1, respectively. The sol–gel membranes displayed higher selectivity for valproate when compared with PVC membranes. These two types of electrodes were coupled to a sequential-injection analysis (SIA) system for the direct determination of valproate in pharmaceutical formulations. The association of Mn(III)TPP-Cl with the sol–gel support inserted in a SIA system provided potentiometric sensors with an analytical range of 1x10^−3–5x10^−2 mol l^−1, with a sample rate of 55 samples per hour and a sample and carrier consumption of 140 and 2,500 μl per determination, respectively.
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Construction and evaluation of PVC and sol-gel sensor membranes based on Mn(III)TPP-Cl. Application to valproate determination in pharmaceutical preparations.
Analytical and Bioanalytical Chemistry, 2005Co-Authors: Emilia M G Santos, Cristina M C M Couto, Alberto N Araujo, M. Conceição B. S. M. MontenegroAbstract:The construction and general performance of new valproate-selective electrodes based on manganese(III) tetraphenylporphyrin [Mn(III)TPP-Cl], as an ionophore, are presented. The ionophore was incorporated into PVC and ceramic membranes (sol–gel) based on methyltriethoxysilane. The influence of membrane composition and pH and the effect of lipophilic cationic and anionic additives in PVC membranes were investigated concerning their influence on the Slope, Response time, selectivity and lifetime of the electrodes. The PVC membrane without additive and the sol–gel membrane presented Slopes and practical limits of detection of −60.8 mV dec−1 and 5x10−6 mol l−1 and −60.3 mV dec−1 and 1×10−4 mol l−1, respectively. The sol–gel membranes displayed higher selectivity for valproate when compared with PVC membranes. These two types of electrodes were coupled to a sequential-injection analysis (SIA) system for the direct determination of valproate in pharmaceutical formulations. The association of Mn(III)TPP-Cl with the sol–gel support inserted in a SIA system provided potentiometric sensors with an analytical range of 1x10−3–5x10−2 mol l−1, with a sample rate of 55 samples per hour and a sample and carrier consumption of 140 and 2,500 μl per determination, respectively.
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determination of gibberellic acid by sequential injection analysis using a potentiometric detector based on mn iii porphyrin with improved characteristics
Journal of the Brazilian Chemical Society, 2004Co-Authors: Emilia M G Santos, Cristina M C M Couto, Alberto N Araujo, Conceicao M B S M Montenegro, Boaventura F ReisAbstract:This work describes the determination of gibberellic acid in growth promoters formulations used in agriculture by sequential injection analysis and potentiometric detection. The potentiometric detectors with improved characteristics used a PVC membrane prepared with Mn(III)tetraphenylporphyrin-Cl as electroactive specie. Different membranes formulated with several ionic additives were compared in order to select the most suitable one concerning Slope, Response time, reproducibility and selectivity. A membrane containing 6 wt% of manganese tetraphenylporphyrin-Cl [(Mn(TPP)Cl], 27 wt% of PVC, 66 wt% of dibutylphthalate (DBP), as mediator solvent, and 1 wt% of sodium tetraphenylborate, as anionic additive, was chosen for analytical applications. When coupled to a SIA system the tubular electrode presented a linear range between 5×10-4 mol L-1 and 8×10-3 mol L-1, a Slope of -64.5 ± 1.6 mV/dec and lower potentiometric selectivity coefficients (log Kpot) than those obtained with the conventional electrodes. Standard deviation of 0.01 and 0.4 (n= 4) and a sampling rate of 30 samples/hour were obtained in the analysis of real samples.
Alberto N Araujo - One of the best experts on this subject based on the ideXlab platform.
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Construction and evaluation of PVC and sol–gel sensor membranes based on Mn(III)TPP-Cl. Application to valproate determination in pharmaceutical preparations
Analytical and Bioanalytical Chemistry, 2006Co-Authors: Emilia M G Santos, Cristina M C M Couto, Alberto N Araujo, M. Conceição B. S. M. MontenegroAbstract:The construction and general performance of new valproate-selective electrodes based on manganese(III) tetraphenylporphyrin [Mn(III)TPP-Cl], as an ionophore, are presented. The ionophore was incorporated into PVC and ceramic membranes (sol–gel) based on methyltriethoxysilane. The influence of membrane composition and pH and the effect of lipophilic cationic and anionic additives in PVC membranes were investigated concerning their influence on the Slope, Response time, selectivity and lifetime of the electrodes. The PVC membrane without additive and the sol–gel membrane presented Slopes and practical limits of detection of −60.8 mV dec^−1 and 5x10^−6 mol l^−1 and −60.3 mV dec^−1 and 1×10^−4 mol l^−1, respectively. The sol–gel membranes displayed higher selectivity for valproate when compared with PVC membranes. These two types of electrodes were coupled to a sequential-injection analysis (SIA) system for the direct determination of valproate in pharmaceutical formulations. The association of Mn(III)TPP-Cl with the sol–gel support inserted in a SIA system provided potentiometric sensors with an analytical range of 1x10^−3–5x10^−2 mol l^−1, with a sample rate of 55 samples per hour and a sample and carrier consumption of 140 and 2,500 μl per determination, respectively.
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Construction and evaluation of PVC and sol-gel sensor membranes based on Mn(III)TPP-Cl. Application to valproate determination in pharmaceutical preparations.
Analytical and Bioanalytical Chemistry, 2005Co-Authors: Emilia M G Santos, Cristina M C M Couto, Alberto N Araujo, M. Conceição B. S. M. MontenegroAbstract:The construction and general performance of new valproate-selective electrodes based on manganese(III) tetraphenylporphyrin [Mn(III)TPP-Cl], as an ionophore, are presented. The ionophore was incorporated into PVC and ceramic membranes (sol–gel) based on methyltriethoxysilane. The influence of membrane composition and pH and the effect of lipophilic cationic and anionic additives in PVC membranes were investigated concerning their influence on the Slope, Response time, selectivity and lifetime of the electrodes. The PVC membrane without additive and the sol–gel membrane presented Slopes and practical limits of detection of −60.8 mV dec−1 and 5x10−6 mol l−1 and −60.3 mV dec−1 and 1×10−4 mol l−1, respectively. The sol–gel membranes displayed higher selectivity for valproate when compared with PVC membranes. These two types of electrodes were coupled to a sequential-injection analysis (SIA) system for the direct determination of valproate in pharmaceutical formulations. The association of Mn(III)TPP-Cl with the sol–gel support inserted in a SIA system provided potentiometric sensors with an analytical range of 1x10−3–5x10−2 mol l−1, with a sample rate of 55 samples per hour and a sample and carrier consumption of 140 and 2,500 μl per determination, respectively.
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determination of gibberellic acid by sequential injection analysis using a potentiometric detector based on mn iii porphyrin with improved characteristics
Journal of the Brazilian Chemical Society, 2004Co-Authors: Emilia M G Santos, Cristina M C M Couto, Alberto N Araujo, Conceicao M B S M Montenegro, Boaventura F ReisAbstract:This work describes the determination of gibberellic acid in growth promoters formulations used in agriculture by sequential injection analysis and potentiometric detection. The potentiometric detectors with improved characteristics used a PVC membrane prepared with Mn(III)tetraphenylporphyrin-Cl as electroactive specie. Different membranes formulated with several ionic additives were compared in order to select the most suitable one concerning Slope, Response time, reproducibility and selectivity. A membrane containing 6 wt% of manganese tetraphenylporphyrin-Cl [(Mn(TPP)Cl], 27 wt% of PVC, 66 wt% of dibutylphthalate (DBP), as mediator solvent, and 1 wt% of sodium tetraphenylborate, as anionic additive, was chosen for analytical applications. When coupled to a SIA system the tubular electrode presented a linear range between 5×10-4 mol L-1 and 8×10-3 mol L-1, a Slope of -64.5 ± 1.6 mV/dec and lower potentiometric selectivity coefficients (log Kpot) than those obtained with the conventional electrodes. Standard deviation of 0.01 and 0.4 (n= 4) and a sampling rate of 30 samples/hour were obtained in the analysis of real samples.