Salicylate-selective membrane electrode based on tin(IV)-tetraphenylporphyrin

• Published in: Analytical chemistry (Washington) 1989-03, Vol.61 (6), p.566-570
• Main Authors: Chaniotakis, N. A, Park, S. B, Meyerhoff, Mark E
• Format: Article
• Language: English
• Subjects: Chemistry; Electrochemistry; Electrodes; Electrodes: preparations and properties; Exact sciences and technology; General and physical chemistry; Hydrogen-Ion Concentration; Ion selective electrodes; Metalloporphyrins; Miscellaneous; Other electrodes; Salicylates - blood; Salicylates - metabolism; Salicylates - urine; Study of interfaces
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac00181a013

The response properties of a new solvent/polymeric membrane electrode with unique selectivity toward anionic salicylate are reported. The electrode is prepared by incorporating 5, 10, 15, 20-tetraphenyl(porphyrinato)tin(IV) dichloride (Sn[TPP]Cl2) into a plasticized poly(vinyl chloride) membrane. The resulting sensor exhibits an anti-Hofmeister selectivity pattern, with high specificity for salicylate over lipophilic inorganic anions (perchlorate, periodate, thiocyanate, iodide, etc.) and biological organic anions (citrate, lactate, acetate). Moderate selectivity over structural analogues of salicylate (3- and 4-hydroxybenzoate, benzoate) is also observed. Radiotracer uptake experiments using [14C]salicylate clearly show that the metal center of the metalloporphyrin is critical for selective salicylate transport in the membrane phase. Minimal response to chloride ions makes the new electrode potentially useful for estimating salicylate levels in biological samples.