1994 Fiscal Year Final Research Report Summary
STUDY ON DEVELOPMENT OF SULFATE-AND PHOSPHATE-SELECTIVE ELECTRODE POLY (VINYL CHLORIDE) MEMBRANE IMPREGNATED WITH METAL CHLORANILATE SALTS FOR ENVIRONMENTAL OR BIOLOGICAL SAMPLES
Grant-in-Aid for General Scientific Research (C)
|OKAYAMA UNIVERSITY OF SCIENCE
KOJIMA Takehiro OKAYAMA UNIVERSITY OF SCIENCE,DEPARTMENT OF CHEMISTRY,ASSOCIATE PROFESSOR, 理学部, 助教授 (00113192)
|Project Period (FY)
1993 – 1994
|Ion Selective Electrode / Sulfate-Sensitive Membrane Electrode / Phosphate-Sensitive Membrane Electrode / Poly (vinyl chloride) / Metall Choranilate Salts
A number of solid-heterogeneous ion selective electrodes for the potentiometric determination of sulfate and phosphate have been made and their properties investigation. The most successful of these electrodes which had a membrane comprising metal chloranilates as the electroactive material, had a sub-Nernstian response to sulfate or phosphate ion at concentrations down to mug/ml at about pH 7.0. A solid-state heterogeneous membrane electrode that is selective to sulfate ions was prepared from PVC membrane impreganted with barium chloranilate. Although the electrode response was under Nernstian (16mV/pSO_4^<2->) it was application to a sulfate concentration range of 10^<-1.5> to 10^<-4>M.The preferable pH range was 6-11 and the response time was about 30s. The electrode remained active for at least 300 measurements, or 3 months. This electrode was used to determine sulfate in natural sea water and organic compounds, with good agreement with standard methods. The electrode was also used as an end-point indicator in the titration of sulphate with barium ion.
The phosphate electrode was prepared from PVC membrane impregnated with lanthanum chloranilate or neodium chloranilate. The electrode had a linear response to log [K_2HPO_4] in the range 1-4, with a slope factor of -29mV per decade. The response of phosphate electrodes of whatever type are likely to be strongly dependent on pH because of the progressive protonation of the phosphate ion. In some studies it has not always been clear whether the electrode was responding to the phosphate, monohydrogen phosphate or dihydrogen phosphate ions.
Research Products (7 results)