Comparative studies on Tb (III)-selective PVC membrane sensors.

Area of Science:

• Analytical Chemistry
• Electrochemistry
• Materials Science

Background:

• Selective detection of terbium (III) ions is crucial for environmental monitoring and various industrial applications.
• Development of ion-selective electrodes (ISEs) with enhanced sensitivity and selectivity remains an active area of research.
• Existing methods for terbium detection often suffer from limitations in selectivity, response time, or operational conditions.

Purpose of the Study:

• To design and characterize a new potentiometric sensor for the selective determination of terbium (III) ions.
• To investigate the influence of different plasticizers and an anion excluder on sensor performance.
• To evaluate the sensor's operational parameters, including pH range, response time, and stability.

Main Methods:

• Synthesis and characterization of N-(2-hydroxyphenyl)-3-(2-hydroxyphenylhydroxyphenylimino)-N-phenylbutanamidine (L(1)) and N,N'-bis((1H-indole-3-yl)methylene)butane-1,4 diamine (L(2)) as ionophores.
• Fabrication of ion-selective electrode membranes incorporating ionophores, potassium tetrakis (p-chloropheny1)borate (KTpClPB), PVC, and various plasticizers (o-NPOE, DBBP, CN, DOP, TEHP).
• Potentiometric measurements to assess sensor response, selectivity, detection limit, working pH range, and response time.

Main Results:

• The optimized membrane composition (ionophore (L(1)):KTpClPB:PVC:o-NPOE in ratio 3.0:5.0:30.0:62.0) demonstrated excellent selectivity for terbium (III) ions.
• The sensor exhibited a wide linear concentration range (3.5 x 10(-7) to 1.0x10(-2)M) with a low detection limit of 1.2 x 10(-7)M.
• A Nernstian slope of 20.0+/-0.5mVdec(-1), a working pH range of 3.5-7.5, and a rapid response time of 11s were achieved.
• The sensor showed satisfactory performance in partially non-aqueous media and maintained stability for up to 3 months.

Conclusions:

• A highly selective and sensitive potentiometric sensor for terbium (III) ions has been successfully developed.
• The sensor demonstrates robust performance, good reproducibility, and long-term stability, making it suitable for practical applications.
• The developed sensor is effective for determining terbium (III) ions in spiked water samples, highlighting its environmental relevance.