The new ferrous-selective modified carbon paste electrodes (I and II) based on 5,5’-(propane-1,3-diylbis(sulfanediyl))bis(3-benzyl-4H-1,2,4-triazol-4-amine) (electrode I, A-ionophore) and 5,5’-(butane-1,4-diyl-bis(s...The new ferrous-selective modified carbon paste electrodes (I and II) based on 5,5’-(propane-1,3-diylbis(sulfanediyl))bis(3-benzyl-4H-1,2,4-triazol-4-amine) (electrode I, A-ionophore) and 5,5’-(butane-1,4-diyl-bis(sulfane- diyl))bis(3-benzyl-4H-1,2,4-triazol-4-amine) (electrode II, B-ionophore) as ionophores are described. These electrodes exhibit Nernstian slopes of 30.2 ± 0.5 and 29.1 ± 0.5 mV·decade-1, linear range of 1.0 × 10-7 - 1.0 × 10-2 mol·L-1 Fe(II) ion and detection limit of 1.0 × 10-7 mol·L-1 Fe(II) ion for electrode (I) and electrode (II), respectively. Both electrodes (I and II) have a fast response time of about 15 sand can be used for at least 3 months. The two electrodes revealed a good selectivity for Fe(II) over a wide variety of other metal ions and could be used in the pH range of 1.8 - 3.0 without any divergence in potential. The proposed sensors were successfully applied for the determination of Fe(II) ion in different real samples.展开更多
Silica gel (SG) was synthesized via acidification of sodium silicate solution then doped with Fˉ or Zr(IV) in molar ratios of F/Si 3/100, and Zr/Si 0.75/100 and 3.75/100 and sintered at 500°C, 800°C and 100...Silica gel (SG) was synthesized via acidification of sodium silicate solution then doped with Fˉ or Zr(IV) in molar ratios of F/Si 3/100, and Zr/Si 0.75/100 and 3.75/100 and sintered at 500°C, 800°C and 1000°C. The samples were investigated by X-ray diffractometry, infrared absorption and Raman spectra, surface area measurement, and inductively coupled plasma-optical emission spectrometry-monitored silica hydrolysis. All samples are mesoporous with BET surface areas 181.5 - 523.9 m2·gˉ1. The surface area of the silica samples decreases as the sintering temperature increases. The hydrolysis process of silica decreases as the sintering temperature increases and as the surface area decreases. The pH and the type of buffer solution affect the hydrolysis of silica samples due to a SN2 reaction mechanism favored in basic media using ammonia buffer. Zr(IV) increases the stability of silica samples against the hydrolysis as confirmed by the structural investigation, surface area and silica hydrolysis. Fˉ observably decreases the silica hydrolysis process when presenting on the surface of SG.展开更多
文摘The new ferrous-selective modified carbon paste electrodes (I and II) based on 5,5’-(propane-1,3-diylbis(sulfanediyl))bis(3-benzyl-4H-1,2,4-triazol-4-amine) (electrode I, A-ionophore) and 5,5’-(butane-1,4-diyl-bis(sulfane- diyl))bis(3-benzyl-4H-1,2,4-triazol-4-amine) (electrode II, B-ionophore) as ionophores are described. These electrodes exhibit Nernstian slopes of 30.2 ± 0.5 and 29.1 ± 0.5 mV·decade-1, linear range of 1.0 × 10-7 - 1.0 × 10-2 mol·L-1 Fe(II) ion and detection limit of 1.0 × 10-7 mol·L-1 Fe(II) ion for electrode (I) and electrode (II), respectively. Both electrodes (I and II) have a fast response time of about 15 sand can be used for at least 3 months. The two electrodes revealed a good selectivity for Fe(II) over a wide variety of other metal ions and could be used in the pH range of 1.8 - 3.0 without any divergence in potential. The proposed sensors were successfully applied for the determination of Fe(II) ion in different real samples.
基金partly funded by the Alexander von Humboldt foundation,Germany,in the frame of a fellowship award.
文摘Silica gel (SG) was synthesized via acidification of sodium silicate solution then doped with Fˉ or Zr(IV) in molar ratios of F/Si 3/100, and Zr/Si 0.75/100 and 3.75/100 and sintered at 500°C, 800°C and 1000°C. The samples were investigated by X-ray diffractometry, infrared absorption and Raman spectra, surface area measurement, and inductively coupled plasma-optical emission spectrometry-monitored silica hydrolysis. All samples are mesoporous with BET surface areas 181.5 - 523.9 m2·gˉ1. The surface area of the silica samples decreases as the sintering temperature increases. The hydrolysis process of silica decreases as the sintering temperature increases and as the surface area decreases. The pH and the type of buffer solution affect the hydrolysis of silica samples due to a SN2 reaction mechanism favored in basic media using ammonia buffer. Zr(IV) increases the stability of silica samples against the hydrolysis as confirmed by the structural investigation, surface area and silica hydrolysis. Fˉ observably decreases the silica hydrolysis process when presenting on the surface of SG.
