Tin organic compounds as neutral carriers for anion selective electrodes

Abstract

Trl-n-octyltln chlorlde acts as a neutral carrler for anlons. Llquld membranes contalnlng thls carrler, ( R ,R )-2,3dlmeth-oxysuccinic acld bls( 1-butylpentyl) ester as plastlclzer, and poly(vlny1 chlorlde) as membrane malrlx show selectlvlly patterns whlch are not In accordance with the sequence obtained for classlcal anlon exchangers. These neutral carrler membranes dlsplay Nernstian electrode functlons for dlfferenl anlons In the I O 9 M to IO-' M concentratlon range. NMR and vapor pressure osmometry studles lndlcate an lnteractlon of the tln organlc compound wlth the chlorlde anlon. The expected mlgrallon of the tin organic compound In the dlrectlon of the anode is demonstrated with an electrodlalytlc transport experlment.A large number of anion-selective liquid membrane electrodes based on classical ion exchangers such as quaternary ammonium salts, phosphonium salts, complexes of 0-phenanthroline, and of other complexing agents have been described (1-4). Electrodes have been proposed for the analysis of Cl-(5-9), NO, (3,9, IO), SCN-(11-13) and other inorganic as well as organic anions. For electrodes based on tetraalkylammonium salts, 35 different detectable anions have been mentioned in ref 1. Usually all these electrodes exhibit roughly the same selectivity sequence with a preference of lipophilic and a rejection of hydrophilic anions (14, 15). In these cases, the free energy of transfer of the anions from the aqueous sample phase to the membrane phase-and therefore the membrane selectivity-is controlled by the free energy of hydration of these ions (4,16-20). This is in contrast to neutral carrier based systems for cations, where the ion selectivity highly depends on the free energy of the interaction of the ions with the ligand (14,21). In the latter case, a wide variety of ion selectivities is made accessible (22).Tin organic compounds have been used as components in anion selective electrodes with response t o C1-(23), HAs0,2-IH2As04-(N), NO, (W), and other species. Although tripropyl tin chloride (26) and other triorgano tin compounds (27) have been found to influence anion transport, it has not yet been properly proved that such tin organic compounds may act as neutral carriers for anions. In this paper, we show that trioctyltin chloride displays anion carrier properties if incorporated in solvent polymeric membranes. EXPERIMENTAL SECTIONCell Assemblies for EMF Studies. For all EMF measurements, cells of the following type were used: Hg, Hg2C12; KC1 (satd)llM LiOAclsample solution llmembrane 110.01 M NaC1; AgC1, Ag The external reference electrode was a double junction saturated calomel electrode with a ceramic diaphragm (for details see ref 28). Measurements were performed with four different membranes of the following compositions: (a) 6 wt % methyltri-ndodecylammonium chloride (MTDDACl), 65 wt % di-n-butyl phthalate (DBP), 29 wt % poly(viny1 chloride) (PVC); (b) 3 wt % MTDDACI, 49 wt % (R,R)-2,3-dimethoxysuccinic acid bis(1-butylpentyl) ester (DMSNE), 48 wt % PVC; (c) 3 wt % tri-noctyltin chloride...

Iodide-selective membrane electrode based on salophen complex of cobalt (III)

“…In the case of ionophores based on different metal ion complex, in addition to the electrostatic interaction between the central metal ion and analyte anions, there is a coordination action between both species involved. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] Thus, the selectivity sequence is dominated by both electrostatic and coordination forces and it is expected that both the nature of the complexed metal ion and the coordination ligand properties play important roles in determining the selectivity of the ionophore towards a specific anion. Recently, there have been a few reports on ionophores that when introduced into solvent polymeric membranes bring about iodide selectivity very divergent from the Hofmeister series.…”

“…Soc. metallophthalocyanines [14][15][16][17] and some lipophilic organometallic compounds, [17][18][19][20][21][22][23] which show anion selectivity in the membranes that differ from the Hofmeister selectivity sequence. The observed anti-Hofmeister behavior arises from a strong interaction between anions and the ionophores used.…”

Influence of a Classical Chelate Effect due to a Covalent Linkage of Ionophore Subunits on the Performance of Corresponding Ion Selective Electrodes

“…22 The membrane compositions were: 1-2 wt% 1, 2, 3, 4 or 5, 64 -66 wt% o-NPOE, 31-33 wt% PVC, and KTpCIPB in a molar ratio of about 20 mol% relative to the carrier. EMF-measurements were performed at 21 f 1° C on cells of the type: Hg;Hg2Cl2, KCl (satd)/ 3M KCl/ sample//membrane//10-2 M LiCI, AgCI; Ag using aqueous solutions of metal chlorides as samples.…”

Highly Selective Thiocyanate Electrode Based on Bis-[N-(2-hydroxyethyl)salicylaldimino]copper(II) Complex as a Neutral Carrier

“…Recently, ever more attention has been focused on electrodes using plasticized poly(vinyl chloride) (PVC) membranes incorporating derivatives of vitamin B12, Co(III), Sn(IV), Mn(II) and Mo(IV) porphyrin complexes, which have shown a remarkable deviation from the Hofmeister pattern. [3][4][5][6][7][8][9] This kind of electrode made it possible to detect ion after perchlorate directly and expediently. It is very important to monitor and determine thiocyanate in spin and electroplate industrial and environment protection, since SCN -can harm humans and aquatic life.…”