ABSTRACT: Cathodic stripping differential pulse voltammetric (CSDPV) procedure was successfully used for the determination of poly(8-roxyquinoline) (PHQ) matrix. The linearity range for the determination of PHQ in the presence (1 mmolL-1) of copper (Cu(II) ion was found to be more sensitive ten times of magnitude higher than the determination of PHQ alone. The lower detection limit was found to be as low as 10 nmolL-1. While, in the case for the determination of Cu(II) ion as a PHQ–Cu(II) chelate, the linearity range is (0 – 4 μmolL-1). The determination of PHQ chain and/or Cu(II) ion was successfully applied in the presence of variety of anions, cations and in an insulating poly(vinyl alcohol) (PVA) matrix. The PVP matrix enhanced the absorbability at the mercury electrode surface which caused increased in the peak high of the chelated Cu(II)

ABSTRACT: Cathodic stripping differential pulse voltammetric (CSDPV) procedure was successfully used for the determination of poly(8-roxyquinoline) (PHQ) matrix. The linearity range for the determination of PHQ in the presence (1 mmolL-1) of copper (Cu(II) ion was found to be more sensitive ten times of magnitude higher than the determination of PHQ alone. The lower detection limit was found to be as low as 10 nmolL-1. While, in the case for the determination of Cu(II) ion as a PHQ–Cu(II) chelate, the linearity range is (0 – 4 μmolL-1). The determination of PHQ chain and/or Cu(II) ion was successfully applied in the presence of variety of anions, cations and in an insulating poly(vinyl alcohol) (PVA) matrix. The PVP matrix enhanced the absorbability at the mercury electrode surface which caused increased in the peak high of the chelated Cu(II)

The insertion of Al(III) cation into a poly(8- Hydroxyquinoline) (PHQ) instead of some metal ions such as Co(II), Ni(II), Zn(II) or Fe(III) ions via cation-exchange mechanism has been studied by several techniques. The presence of Al(III) and the absence of Co(II) cations has been proved by elemental analysis of the polymer chelates product. Molecular mechanics (MM?) calculations showed that the potential energy (PE, kJ mol-1) of the optimum molecular geometric structure (OMG) of the PHQ–Al(III) matrix is about seventy-six (76.185) greater than the PE of the PHQ–Co(II) complex. The TGA thermograms show that the PHQ–Al(III) matrix is thermally unstable than the PHQ–Co(II) complex under the same conditions. These observations indicate that the PHQ–Al(III) is expanded coil-like form. So, the thermal decomposition of PHQ–Al(III) complex is easy than the compacted coil-likes form of PHQ–Co(II) complex. The incorporation of Al(III) ion via cation-exchange properties have been investigated by spectrophotometric technique. The decrease of the absorbance at about *370 nm of PHQ–Co(II) complex associated with increasing concentration of Al(III) revealed the replacement of that metal ion by Al(III) into PHQ chain. The cation-exchange constant(Kex) of the divalent ions [Ni(II), Co(II), Cr(II), Zn(II), Mn(II), Mg(II) and Cu(II)] from PHQ–M(II) by the additions of Al(III) according to the following series: Ni(II)[Co(II)[Cr(II)[Cu(II)[Zn(II)[Mn(II)[Mg(II).

The insertion of Al(III) cation into a poly(8- Hydroxyquinoline) (PHQ) instead of some metal ions such as Co(II), Ni(II), Zn(II) or Fe(III) ions via cation-exchange mechanism has been studied by several techniques. The presence of Al(III) and the absence of Co(II) cations has been proved by elemental analysis of the polymer chelates product. Molecular mechanics (MM?) calculations showed that the potential energy (PE, kJ mol-1) of the optimum molecular geometric structure (OMG) of the PHQ–Al(III) matrix is about seventy-six (76.185) greater than the PE of the PHQ–Co(II) complex. The TGA thermograms show that the PHQ–Al(III) matrix is thermally unstable than the PHQ–Co(II) complex under the same conditions. These observations indicate that the PHQ–Al(III) is expanded coil-like form. So, the thermal decomposition of PHQ–Al(III) complex is easy than the compacted coil-likes form of PHQ–Co(II) complex. The incorporation of Al(III) ion via cation-exchange properties have been investigated by spectrophotometric technique. The decrease of the absorbance at about *370 nm of PHQ–Co(II) complex associated with increasing concentration of Al(III) revealed the replacement of that metal ion by Al(III) into PHQ chain. The cation-exchange constant(Kex) of the divalent ions [Ni(II), Co(II), Cr(II), Zn(II), Mn(II), Mg(II) and Cu(II)] from PHQ–M(II) by the additions of Al(III) according to the following series: Ni(II)[Co(II)[Cr(II)[Cu(II)[Zn(II)[Mn(II)[Mg(II).

The insertion of Al(III) cation into a poly(8- Hydroxyquinoline) (PHQ) instead of some metal ions such as Co(II), Ni(II), Zn(II) or Fe(III) ions via cation-exchange mechanism has been studied by several techniques. The presence of Al(III) and the absence of Co(II) cations has been proved by elemental analysis of the polymer chelates product. Molecular mechanics (MM?) calculations showed that the potential energy (PE, kJ mol-1) of the optimum molecular geometric structure (OMG) of the PHQ–Al(III) matrix is about seventy-six (76.185) greater than the PE of the PHQ–Co(II) complex. The TGA thermograms show that the PHQ–Al(III) matrix is thermally unstable than the PHQ–Co(II) complex under the same conditions. These observations indicate that the PHQ–Al(III) is expanded coil-like form. So, the thermal decomposition of PHQ–Al(III) complex is easy than the compacted coil-likes form of PHQ–Co(II) complex. The incorporation of Al(III) ion via cation-exchange properties have been investigated by spectrophotometric technique. The decrease of the absorbance at about *370 nm of PHQ–Co(II) complex associated with increasing concentration of Al(III) revealed the replacement of that metal ion by Al(III) into PHQ chain. The cation-exchange constant(Kex) of the divalent ions [Ni(II), Co(II), Cr(II), Zn(II), Mn(II), Mg(II) and Cu(II)] from PHQ–M(II) by the additions of Al(III) according to the following series: Ni(II)[Co(II)[Cr(II)[Cu(II)[Zn(II)[Mn(II)[Mg(II).

Incorporation of various metal ions into a poly(8-hydroxyquinoline) (PHQ)matrix via a complexation mechanism to form the corresponding coordination polymers was investigated experimentally and computationally. TGA, DTG, MS, and elemental analysis measurements show that the polymeric chelates of copper(II) ion with the PHQ matrix have a hydrophilic nature about two-times stronger than the salt (i.e., copper acetate monohydrate). The results of DSC, TGA, and DTG suggest that the PHQ-Cu(II) matrix is more thermally stable than the copper acetate complex. A first-order derivative treatment of the UV-visible absorption spectra of the matrixes under investigation is sensitive to at least 1.5-times that of the normal (zero-order derivative) spectra. Analysis of the absorbance vs. mole fraction data for metal ions such as Cu(II), Ni(II), Co(II), and Fe(III), which are coordinated to the PHQ matrix, afforded information about the equilibria that prevailed in solution. The largest stability constant (log b) corresponds to a stiochiometric ratio of 2PHQ:1Mn+. The results are supported by elemental analysis, TGA, DTG, and mass spectroscopic measurements, and are consistent with molecular mechanics (MM+) calculations. A simple, rapid and sensitive method for the spectrophotometric determination of trace amounts of Cu(II) ion in solution by coordination with the PHQ matrix is proposed. The method has been applied successfully to the determination of Cu(II) ion in Heamoton capsule samples (mg/g). The proposed method is in excellent agreement with the determination of Cu(II) ion by atomic absorption spectrometry.

Incorporation of various metal ions into a poly(8-hydroxyquinoline) (PHQ)matrix via a complexation mechanism to form the corresponding coordination polymers was investigated experimentally and computationally. TGA, DTG, MS, and elemental analysis measurements show that the polymeric chelates of copper(II) ion with the PHQ matrix have a hydrophilic nature about two-times stronger than the salt (i.e., copper acetate monohydrate). The results of DSC, TGA, and DTG suggest that the PHQ-Cu(II) matrix is more thermally stable than the copper acetate complex. A first-order derivative treatment of the UV-visible absorption spectra of the matrixes under investigation is sensitive to at least 1.5-times that of the normal (zero-order derivative) spectra. Analysis of the absorbance vs. mole fraction data for metal ions such as Cu(II), Ni(II), Co(II), and Fe(III), which are coordinated to the PHQ matrix, afforded information about the equilibria that prevailed in solution. The largest stability constant (log b) corresponds to a stiochiometric ratio of 2PHQ:1Mn+. The results are supported by elemental analysis, TGA, DTG, and mass spectroscopic measurements, and are consistent with molecular mechanics (MM+) calculations. A simple, rapid and sensitive method for the spectrophotometric determination of trace amounts of Cu(II) ion in solution by coordination with the PHQ matrix is proposed. The method has been applied successfully to the determination of Cu(II) ion in Heamoton capsule samples (mg/g). The proposed method is in excellent agreement with the determination of Cu(II) ion by atomic absorption spectrometry.

Incorporation of various metal ions into a poly(8-hydroxyquinoline) (PHQ)matrix via a complexation mechanism to form the corresponding coordination polymers was investigated experimentally and computationally. TGA, DTG, MS, and elemental analysis measurements show that the polymeric chelates of copper(II) ion with the PHQ matrix have a hydrophilic nature about two-times stronger than the salt (i.e., copper acetate monohydrate). The results of DSC, TGA, and DTG suggest that the PHQ-Cu(II) matrix is more thermally stable than the copper acetate complex. A first-order derivative treatment of the UV-visible absorption spectra of the matrixes under investigation is sensitive to at least 1.5-times that of the normal (zero-order derivative) spectra. Analysis of the absorbance vs. mole fraction data for metal ions such as Cu(II), Ni(II), Co(II), and Fe(III), which are coordinated to the PHQ matrix, afforded information about the equilibria that prevailed in solution. The largest stability constant (log b) corresponds to a stiochiometric ratio of 2PHQ:1Mn+. The results are supported by elemental analysis, TGA, DTG, and mass spectroscopic measurements, and are consistent with molecular mechanics (MM+) calculations. A simple, rapid and sensitive method for the spectrophotometric determination of trace amounts of Cu(II) ion in solution by coordination with the PHQ matrix is proposed. The method has been applied successfully to the determination of Cu(II) ion in Heamoton capsule samples (mg/g). The proposed method is in excellent agreement with the determination of Cu(II) ion by atomic absorption spectrometry.

The electrochemical activity of poly(8-hydroxyquinoline(PHQ) in acid and alkaline media has been investigated by use of differential pulse polarography(DPP). The reduction peak height (Ip) of PHQ in universal buffer solutions is not useful as an analytical signal, because it is highly affected by hydrogen evolution in acid media and appears as a small peak located at more negative potential values in alkaline media. A new and highly sensitive reduction peak (Ep=–0.45, pH 9.25) appears, however, after addition of trace amounts of PHQ to Cu(II), or vice versa. This reduction peak is a result of the reduction of Cu(II) chelates in the PHQ–Cu(II) complex and is highly promising for the trace determination of PHQ at nanomolar and submicromolar levels. The response current (Ip/μA) for the reduction peak of Cu(II) chelates in a PHQ–Cu(II) matrix results in sensitivity to the concentration of PHQ at least three orders of magnitude higher than that for the reduction peak of PHQ alone under the same conditions. The limit of detection is as low as 5.264 ppb (μg L–1). The effect of a variety of anions and cations and of an insulating poly(vinyl alcohol) (PVA)matrix has been investigated. Electroactive PHQ–Cu(II) at a level of 0.685% could induce a current of approximately 240 nA in an insulating PVA matrix, suggesting possible application for the preparation of a PHQ–Cu(II)– PVA electroactive composite.

The electrochemical activity of poly(8-hydroxyquinoline(PHQ) in acid and alkaline media has been investigated by use of differential pulse polarography(DPP). The reduction peak height (Ip) of PHQ in universal buffer solutions is not useful as an analytical signal, because it is highly affected by hydrogen evolution in acid media and appears as a small peak located at more negative potential values in alkaline media. A new and highly sensitive reduction peak (Ep=–0.45, pH 9.25) appears, however, after addition of trace amounts of PHQ to Cu(II), or vice versa. This reduction peak is a result of the reduction of Cu(II) chelates in the PHQ–Cu(II) complex and is highly promising for the trace determination of PHQ at nanomolar and submicromolar levels. The response current (Ip/μA) for the reduction peak of Cu(II) chelates in a PHQ–Cu(II) matrix results in sensitivity to the concentration of PHQ at least three orders of magnitude higher than that for the reduction peak of PHQ alone under the same conditions. The limit of detection is as low as 5.264 ppb (μg L–1). The effect of a variety of anions and cations and of an insulating poly(vinyl alcohol) (PVA)matrix has been investigated. Electroactive PHQ–Cu(II) at a level of 0.685% could induce a current of approximately 240 nA in an insulating PVA matrix, suggesting possible application for the preparation of a PHQ–Cu(II)– PVA electroactive composite.