Sensitive flow-injection amperometric detection of iodide using Mn3+ and As3+

Area of Science:

• Analytical Chemistry
• Electrochemistry
• Environmental Science

Background:

• Accurate iodide determination is crucial for various applications, including environmental monitoring and nutritional analysis.
• Existing methods for iodide quantification can be time-consuming or lack the required sensitivity and selectivity.

Purpose of the Study:

• To develop a rapid, selective, and sensitive kinetic flow-injection method for iodide determination.
• To validate the method's performance and assess its applicability to diverse sample matrices.

Main Methods:

• Kinetic flow-injection analysis (FIA) coupled with amperometric detection on a platinum electrode.
• Utilized the catalytic effect of iodide on the Mn3+-As3+ reaction in sulfuric acid medium.
• Established a calibration curve and determined the limit of detection (LOD) and relative standard deviations (RSD).

Main Results:

• The developed method demonstrated linearity over a wide iodide concentration range (5.0 x 10(-7) to 1.0 x 10(-4) mol/L).
• Achieved a low limit of detection (LOD) of 5.0 x 10(-9) mol/L for iodide.
• Exhibited good precision with RSDs of 1.68% and 3.03% for different iodide concentrations.

Conclusions:

• The kinetic flow-injection method provides a reliable and efficient approach for iodide quantification.
• Successfully applied to the determination of iodide in complex matrices such as water, salts, fodder, organic substances, and human blood sera.
• Results showed good agreement when compared to standard AOAC and kinetic spectrophotometric methods.