Neutral carriers based polymeric membrane electrodes for selective determination of mercury (II)

Area of Science:

• Analytical Chemistry
• Electrochemistry
• Materials Science

Background:

• Mercury ion (Hg2+) contamination poses significant environmental and health risks.
• Development of selective and sensitive detection methods for Hg2+ is crucial for monitoring.
• Ion-selective electrodes (ISEs) offer a promising platform for electrochemical sensing.

Purpose of the Study:

• To develop and characterize novel mercury ion-selective membrane electrodes.
• To investigate the influence of various components on electrode performance.
• To evaluate the analytical applicability of the developed electrodes for Hg2+ determination.

Main Methods:

• Potentiometric measurements using membrane electrodes incorporating 2-amino-6-purinethiol (I(1)) and 5-amino-1, 3, 4-thiadiazole-2-thiol (I(2)) as ionophores.
• Optimization of membrane composition, plasticizers (e.g., dioctylphthalate), and additives (e.g., sodium tetraphenylborate).
• Testing of ion selectivities, response characteristics, limit of detection, and stability.

Main Results:

• The optimized electrode (3.17% I(1): 31.7% PVC: 63.4% DOP: 1.58% NaTPB) exhibited a Nernstian response for Hg2+ over a wide concentration range (7.0 x 10(-8) - 1.0 x 10(-1) M).
• A low limit of detection (4.4 x 10(-8) M), fast response time (10s), and good selectivity against common cations were achieved.
• The electrode demonstrated stable performance for 2 months and was successfully applied to determine Hg2+ in environmental and biological samples, even in the presence of surfactants.

Conclusions:

• Novel ion-selective membrane electrodes based on I(1) and I(2) show excellent performance for Hg2+ detection.
• The developed electrodes offer a sensitive, selective, and stable method for mercury monitoring.
• These electrodes have practical utility for analyzing Hg2+ in complex real-world samples.