Use of tin (IV) porhyrins as Ionophores for the construction of phthalate-selective electrodes: Influence of the structure and membrane composition on their response properties

• Type: Article in International Scientific Journal
• Date: 2005

Authors

Santos, EMG (Author) Other; Araugo, AN (Author) FFUP; Couto, CMCM (Author) Other; Montenegro, MCBSM (Author) FFUP

Journal

Title: Electroanalysis

Vol. 17 No. 14

Pages: 1945-1951

ISSN: 1040-0397

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 3 Citations

ISI Web of Science

Scopus - 3 Citations

Scientific classification

CORDIS: Health sciences

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-000-0MN

DOI: 10.1002/elan.200403273

Resumo (PT): Tin(IV) porphyrins derivatives were used as ionophores for phthalate selective electrodes preparation. The influence of ionophore structure and membrane composition (amount of incorporated ionic sites) on the electrode response, selectivity and long-term stability were studied. Poly(vinyl chloride) polymeric membranes plasticized with o-NPOE (o-nitrophenyloctylether) and containing Sn(IV)-tetraphenylporphyrin (TPP) dichloride (Sn(IV)[TPP]Cl2) or Sn(IV)-octaethylporphyrin (OEP) dichloride (Sn(IV)[OEP]Cl2), and in some cases incorporating lipophilic cationic (tetraocthylammonium bromide - TOABr) and anionic (sodium tetraphenylborate - NaTPB and potassium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate-KTFPB) additives, were prepared and their potentiometric characteristics compared. Both ionophores are shown to operate via a neutral mechanism, and the addition of 10 mol % of lipophilic quaternary ammonium salt derivative to the membrane is required to achieve optimal electrode performance. The potentiometric units prepared, with Sn(IV)[TPP]Cl2 (Type A) or Sn(IV)[OEP]Cl2 (Type B) without additives, presented a slope of -52.8 mV dec-1 and -58.8 mV dec-1 and LLLR of 9.9×10-5 mol L-1 and 9.9×10-6 mol L-1, respectively. The units prepared using the same metalloporphyrins and incorporating 10% mol TOABr presented a slope of -55.0 mV dec-1 and -57.8 mV dec-1 and LLLR of 5.0×10-7 mol L-1 and 3.0×10-7 mol L-1. Their analytical usefulness was assessed by potentiometric determinations of phthalate in water and industrial products providing results that presented recoveries of about 100%. Keywords <br> <br> Phthalate • Tin(IV) • Metalloporphyrins • Ion-selective electrode • Potentiometry <br> <a target="_blank" href="http://www3.interscience.wiley.com/journal/111085156/abstract"> Texto integral</a> <br> <br>

Abstract (EN): Tin(IV) porphyrins derivatives were used as ionophores for phthalate selective electrodes preparation. The influence of ionophore structure and membrane composition (amount of incorporated ionic sites) on the electrode response, selectivity and long-term stability were studied. Poly(vinyl chloride) polymeric membranes plasticized with o-NPOE (o-nitrophenyloctylether) and containing Sn(IV)-tetraphenylporphyrin (TPP) dichloride (Sn(IV)[TPP]Cl-2) or Sn(IV)-octaethylporphyrin (OEP) dichloride (Sn(IV)[OEP]Cl2), and in some cases incorporating lipophilic cationic (tetraocthylammonium bromide - TOABr) and anionic (sodium tetraphenylborate - NaTPB and potassium tetrakis[3,5-bis(trifluoromethyl) phenyl]borate-KTFPB) additives, were prepared and their potentiometric characteristics compared. Both ionophores are shown to operate via a neutral mechanism, and the addition of 10 mol % of lipophilic quaternary ammonium salt derivative to the membrane is required to achieve optimal electrode performance. The potentiometric units prepared, with Sn(IV)[TPP]Cl-2 (Type A) or Sn(IV)[OEP]Cl-2 (Type B) without additives, presented a slope of - 52.8 mV dec(-1) and - 58.8 mV dec(-1) and LLLR of 9.9 x 10(-5) mol L-1 and 9.9 x 10(-6) mol L-1, respectively. The units prepared using the same metalloporphyrins and incorporating 10% mol TOABr presented a slope of - 55.0 mV dec(-1) and - 57.8 mV dec(-1) and LLLR of 5.0 x 10(-7) mol L-1 and 3.0 x 10(-7) mol L-1. Their analytical usefulness was assessed by potentiometric determinations of phthalate in water and industrial products providing results that presented recoveries of about 100%.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7