Potentiometric Performance of Silver Ion-Selective Electrodes Based on Tridentate Schiff Base Derivatives

Abstract

The electrode membrane solvent, o-nitrophenyloctyl ether (o-NPOE), and the anionic excluder, potassium tetrakis (4-chlorophenyl) borate (KTpClPB), were purchased from Tokyo Technology, Omiya, Asahi, Japan To examine the directivity for improving the silver ion discrimination ability of a Schiff base, three kinds of tridentate ligands were synthesized and compared with the similar quadridentate ligand as the silver ionophore. Among the Schiff base derivatives tested, 3-(2-pyridylethylimino)-2-butanoneoxime, having one oxime and a pyridine substituent, was found to be the best ionophore for a silver-ion electrode. The electrode based on this derivative exhibited good silver-ion selectivity, -log K pot Ag + ,K + = 3.8, comparable to that of a quadridentate Schiff base, N,N′-bis(2′-hydroxyimino-1′-phenylpropyleden)-1,3-propanediamine, reported previously, except for a pseudo Nernstian response (35.6 mV decade -1 ) with a wide silver-ion activity change in the activity change from 5.0 × 10 -7 to 7.9 × 10 -2 mol dm -3 .

Effect of π Electrons on the Detection of Silver Ions by Ion-selective Electrodes Containing Tripodal Broom Molecules as an Ionophore

“…15 To introduce allyl, propargyl, or propyl groups into the tripodal broom compounds, sodium hydride (60% in oil) was added to a solution of A-0 in dry dimethylformamide (DMF, 100 cm 3 ) under a nitrogen atmosphere. The corresponding bromide reactant was added dropwise to the mixture over 30 min, and then the resulting mixture was stirred for 24 h at room temperature.…”

“…For example, ionophores containing nitrogen or sulfur atoms, which are soft ligands according to the "hard and soft acids and bases" theory, have been utilized to prepare ion-selective electrodes because of their high affinity for soft metals, such as silver, thallium and mercury ions, and so on. [1][2][3][4][5][6][7] However, ionophores containing nitrogen or sulfur atoms tend to be influenced by the pH. Moreover, the strong affinity of nitrogen and sulfur atoms for soft metal ions at the interface of membranes causes low selectivity, slow response, and weak sensitivity.…”

N,N′-Bis(3-methyl-1-phenyl-4-benzylidine-5-pyrazolone)propylenediamine Schiff base as a neutral carrier for silver (I) ion-selective electrodes

“…However, few attempts based on other binding sites; nitrogen and/or oxygen, have been reported [4,[16][17][18][19][20][21][22][23][24], such as bis-pyridine tetramide [16], corrole [17], bis-oxime derivative diaza-crown ether [18], and calixarenes [19][20][21][22]. In most cases, these ionophores showed less discrimination of transition and alkali metal ions when compared with sulfur-containing ionophores.…”

A Novel Wire‐Type Lead‐Selective Electrode Based on Bis (1'‐Hydroxy‐2'‐Acetonaphthone)‐2,2'‐Diiminodiethylamine

“…These molecules are widely used for analytical proposes such as their use as extracting agents in liquid-liquid, 3-7 solid phase [8][9][10] and cloud point 11 extraction processes. In addition, the incorporation of Schiff base ligands in PVC-membranes for fabricating a variety of cation [12][13][14][15][16][17][18] and anion [19][20][21][22] selective potentiometric sensors have been reported.…”