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Thiocyanate-selective electrode based on unsymmetrical benzoN(4) nickel(II) macrocyclic complexes
A Abbaspour1, M A Kamyabi, A R Esmaeilbeig
1Chemistry Department, College of Science, Shiraz University, Shiraz 71454, Iran.
Talanta
|October 31, 2008
Summary
New PVC-based membrane electrodes using nickel(II) macrocyclic complexes show high selectivity for thiocyanate (SCN-) detection. This sensor accurately determines thiocyanate levels in biological samples, distinguishing smokers from nonsmokers.
Area of Science:
- Analytical Chemistry
- Electrochemistry
- Materials Science
Background:
- Ion-selective electrodes (ISEs) are crucial for detecting specific ions in various matrices.
- Macrocyclic complexes offer unique properties for ion recognition and sensing applications.
- Developing selective and sensitive sensors for thiocyanate is important for clinical and environmental monitoring.
Purpose of the Study:
- To explore unsymmetrical benzoN(4) nickel(II) macrocyclic complexes as ionophores for PVC-based membrane electrodes.
- To evaluate the performance of the developed electrode for selective thiocyanate (SCN-) detection.
- To assess the sensor's applicability in real-world sample analysis, including biological fluids.
Main Methods:
- Synthesis and characterization of unsymmetrical benzoN(4) nickel(II) macrocyclic complexes.
- Fabrication of PVC-based membrane electrodes incorporating the synthesized macrocyclic complexes.
- Electrochemical characterization of the electrodes, including potentiometric measurements, Nernstian response, working concentration range, and pH stability.
- Selectivity testing against various interfering anions.
- Application of the electrode in potentiometric titration and direct determination of thiocyanate in urine and saliva samples.
Main Results:
- The PVC-based membrane electrode incorporating the nickel(II) macrocyclic complex demonstrated excellent selectivity for SCN-.
- The electrode exhibited a wide working concentration range (1.4x10(-7)-0.1 M) and a stable Nernstian slope (-59.7+/-0.9 mV/decade) over a broad pH range (3.5-10.5).
- The sensor showed a rapid response time (5 s) and high selectivity against common anions.
- Successful application in potentiometric titration of SCN- and direct determination in biological samples (urine, saliva).
Conclusions:
- Unsymmetrical benzoN(4) nickel(II) macrocyclic complexes are effective ionophores for developing highly selective SCN- sensors.
- The proposed PVC-based membrane electrode offers a fast, selective, and reliable method for thiocyanate determination.
- The sensor's ability to analyze biological samples provides a valuable tool for distinguishing between smokers and nonsmokers based on thiocyanate levels.
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