Neutral-carrier-based ion-selective electrodes

Bidentate organophosphorus compounds as ionophores for calcium- and uranyl-selective electrodes

“…A change in the electrode function slope with an increase in the uranium(v1) concentration, more noticeable for hydrochloric acid solutions, is probably associated with the formation and transport of singly charged U02XS,,+ complexes [equation ( 3 electrode function slope with an increase in the p H of the solution, and also with increasing uranium(v1) concentrations, can be explained by the fact that, together with the U02Sn2+ and U02XS,+ complex formation reactions, an increasing contribution to the exchange current is being made by the U020HS,+ complex. Hence, together with reaction (2), a substantial contribution to the potential can be made by the distribution of the U022+ ion according to reaction (3). In order to eliminate the effect of anions, KTPB o r KTCPB was introduced into the membrane.…”

Bis- and Oligo(benzocrown ether)s

“…22 However, the corresponding photoresponsive azoxybis(benzocrown ether) (13) was obtained by using powdered zinc as the catalyst in the presence of an electron-transfer agent (a polymer containing benzylpyridinium chloride) (Scheme 3, procedure D). 44 The photoisomerization and thermal isomerization of these biscrowns were studied.22,23'44 Amide-containing bis(benzo-12-crown-4) derivatives [14][15][16] (see Table 1) were synthesized by acylation of 4'-aminobenzo-12-crown-4 (S10), obtained by the reduction of S7, with the appropriate diacid dichlorides (Scheme 4, procedure E)46,46 or EDTA dianhydride (procedure F).47 Solvent extraction of alkali metal picrates with bis(crown ether) 14 was studied. 45 With two carboxyl groups on the bridge, biscrown 16 is water soluble, therefore its complexing properties can be studied in water.…”

Crown ether-based structures for sensitive electrochemical detection

“…4 Different crown ether-based structures have been exploited for constructing chemically modified electrodes, which offer the possibility of selective complexation of a cation. [5][6][7][8] In a previous article, 9 we reported the application of a siloxane-crown ether polyamide in the electrochemical detection of lead (Pb) at parts per billion (ppb) levels. Heavy metal contaminations constitute a severe threat to human health and environment, and Pb is a general metabolic poison and enzyme inhibitor, which can cause mental retardation and semipermanent brain damage in young children.…”