Liquid membrane electrodes for nucleotides based on sapphyrin, cytosine-pendant triamine and neutral cytosine derivative as sensory elements

Abstract

A number of anion-selective lectrodes have been developed by the use of alkyhin compounds, vitamin B,, and metalloporphyrin derivatives, diphosphonium and bis(quaternary ammonium) salts, and macrocyclic polyamines. Of these, the macrocyclic polyamiue electrodes are characteristic in that the host molecule functions as an anion receptor by multiprotonation at the membrane surface [l-3], and as a remarkable feature, have the ability to diiriminate among the adenine nucleotides according to the difference in the number of negative charges. However, since protonated macrocyclic polyamines appear to bind mainly to the phosphate group of nucleotides, it would be difficult to effect discrimination among similarly charged nucleotides bearing different kinds of bases. On the other hand, some new types of receptors for nucleotides, e.g., cytosiue derivatives [4] and Kemp’s acid derivatives [S], have been developed. These exploit several types of recognition sites, namely: (1) a basepairing site for nucleic bases such as cytosine and imide moieties; (2) a rr-rr stacking site for nucleic bases such as naphthalene and acridine moieties; and (3) an electrostatic binding site for phosphate groups such as protonated amine and guanidiniutn moieties. In this paper, we wish to report potentiometric response properties for nucleotides displayed by four