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Epoxy Matrix Membrane Potentiometric Sensor Based on Zirconium Titanium Phosphate Ion Exchanger for Flow Injection Analysis of Nitrite
Author(s) -
Hassan Saad S. M.,
Marei Sayed A.,
Badr I. H.,
Arida H. A.
Publication year - 2000
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/1521-4109(200011)12:16<1312::aid-elan1312>3.0.co;2-l
Subject(s) - potentiometric titration , chemistry , inorganic chemistry , nitrite , ion exchange , zirconium , zirconium phosphate , detection limit , membrane , phosphate , nuclear chemistry , chromatography , ion , organic chemistry , biochemistry , nitrate
Preparation, characterization, origin of response and applications of a potentiometric sensor based on the use of a zirconium titanium phosphate (ZTP)‐epoxy membrane are described. Zirconium titanium phosphate (ZTP) cationic exchanger embedded in an epoxy matrix is converted into a hydrated zirconium oxide anion exchanger which responds to many anionic species. A sensor based on this exchanger exhibits near‐Nernstian response for nitrite and other anions over the concentration range 10 –1 –10 –5 M. Under optimized conditions, the gas dialyzer/flow‐injection system provides a throughput of ca. 60 samples per hour with a high selectivity for nitrite ion over most common anions and acidic gas releasing species. Determination of nitrite at levels as low as 5×10 –4 M or less in the presence of sulfite and sulfide ions is performed by using a modified carrier buffer stream (10 –2 M MES, pH 5.5 containing formaldehyde and Pb 2+ ). Significant advantages are offered by the ZTP‐epoxy membrane based sensor including a long 1ifetime (>2 years), excellent stability and reproducibility (ca. 1 mV), fast response time (<30 s), wide pH working range (pH 4.5–8), low detection limit (4×10 –5 M) and high thermal stability(up to 80 °C).