Evaluation of trace heavy metal levels in soil samples using an ionic liquid modified carbon paste electrode

Area of Science:

• Electrochemistry
• Analytical Chemistry
• Materials Science

Background:

• Traditional carbon paste electrodes often use paraffin oil, which can limit electrochemical performance.
• Ionic liquids offer unique properties for electrochemical applications, including enhanced stability and conductivity.
• Developing sensitive and reliable methods for detecting trace heavy metals is crucial for environmental monitoring.

Purpose of the Study:

• To develop a novel ionic liquid modified carbon paste electrode for heavy metal detection.
• To investigate the electrochemical performance of the modified electrode compared to traditional ones.
• To assess the electrode's efficacy in determining cadmium and lead in soil samples.

Main Methods:

• Modification of a carbon paste electrode with n-octylpyridinium hexafluorophosphate (OPFP).
• Electrochemical deposition of a bismuth film onto the modified electrode.
• Stripping voltammetry for the simultaneous detection of cadmium and lead.
• Optimization of deposition parameters (potential, time) and buffer conditions (pH).

Main Results:

• The OPFP-modified electrode exhibited superior electrochemical activity compared to paraffin oil-based electrodes.
• Well-defined and separate stripping voltammetric peaks were obtained for cadmium and lead.
• A linear detection range of 1.0–100.0 μg L⁻¹ was achieved for both metals.
• Low detection limits of 0.10 μg L⁻¹ for cadmium and 0.12 μg L⁻¹ for lead were determined.
• Successful application in the analysis of cadmium and lead in soil sample extracts.

Conclusions:

• The developed ionic liquid modified carbon paste electrode is sensitive, reliable, and effective for trace heavy metal determination.
• The electrode offers a promising alternative for environmental monitoring of cadmium and lead.
• The use of ionic liquids enhances the performance of carbon paste electrodes in electrochemical sensing.