title: Determination of cobalt ions at nano-level based on newly synthesized pendant armed macrocycle by polymeric membrane and coated graphite electrode.
abstract: Poly(vinylchloride) (PVC) based membranes of macrocycles 2,3,4:9,10,11-dipyridine-1,3,5,8,10,12-hexaazacyclotetradeca-2,9-diene (L(1)) and 2,3,4:9,10,11-dipyridine-1,5,8,12-tetramethylacrylate-1,3,5,8,10,12-hexaazacyclotetradeca-2,9-diene (L(2)) with NaTPB and KTpClPB as anion excluders and dibutylphthalate (DBP), benzyl acetate (BA), dioctylphthalate (DOP), o-nitrophenyloctyl ether (o-NPOE) and tri-n-butylphosphate (TBP) as plasticizing solvent mediators were prepared and investigated as Co(2+) selective electrodes. The best performance was observed with the membranes having the composition L(2):PVC:TBP:NaTPB in the ratio of 6:39:53:2 (w/w; mg). The performance of the membrane based on L(2) was compared with polymeric membrane electrode (PME) and coated graphite electrode (CGE). The PME exhibits detection limit of 4.7x10(-8)M with a Nernstian slope of 29.7 mV decade(-1) of activity between pH 2.5 and 8.5 whereas CGE exhibits the detection limit of 6.8x10(-9)M with a Nernstian slope of 29.5 mV decade(-1) of activity between pH 2.0 and 9.0. The response time for PME and CGE was found to be 11 and 8s, respectively. The CGE has been found to work satisfactorily in partially non-aqueous media up to 35% (v/v) content of methanol, ethanol and 25% (v/v) content of acetonitrile and could be used for a period of 4 months. The CGE was successfully applied for the determination of Co(2+) in real and pharmaceutical samples and as an indicator electrode in potentiometric titration of cobalt ion.
authors.affiliation: Department of Chemistry, Indian Institute of Technology-Roorkee, Roorkee, India. akscyfcy@iitr.ernet.in
authors.forename: Ashok K
authors.initials: AK
authors.lastname: Singh
authors.forename: Prerna
authors.initials: P
authors.lastname: Singh
authors.forename: G
authors.initials: G
authors.lastname: Bhattacharjee
mesh_terms: D003035:Cobalt / Q000032:analysis* / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004784:Environmental Monitoring; D005618:Fresh Water / Q000032:analysis / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D017736:Ion-Selective Electrodes; D007477:Ions / Q000032:analysis / Q000737:chemistry; D007700:Kinetics; D008567:Membranes, Artificial; D015394:Molecular Structure; D017830:Octoxynol / Q000737:chemistry; D010755:Organophosphates / Q000737:chemistry; D010968:Plasticizers / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D011143:Polyvinyl Chloride / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012623:Seawater / Q000032:analysis / Q000737:chemistry; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry; D014803:Vitamin B Complex / Q000032:analysis / Q000737:chemistry
chemical_list: D007477:Ions; D008567:Membranes, Artificial; D010755:Organophosphates; D010968:Plasticizers; D011108:Polymers; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D014803:Vitamin B Complex; D012967:Sodium Dodecyl Sulfate; D003035:Cobalt; D006108:Graphite; D011143:Polyvinyl Chloride; D017830:Octoxynol; C009524:tributyl phosphate; C009405:tetrabutylammonium