New sensor design enables faster, cheaper detection of iodide contamination
Researchers have developed a miniaturized electrode that detects iodide ions with high precision and stability for over two months without degradation. The advance could streamline water quality testing, pharmaceutical manufacturing, and nuclear facility monitoring—applications where rapid, reliable iodide detection directly impacts safety and compliance costs.
Originaltitel: A Nano-Sized Poly(aniline-co-thiophene) Based Solid-Contact Screen-Printed Electrode for Batch and Continuous Potentiometric Determination of Iodide
Two approaches are described for construction of a screen-printed planar electrode (SPE) for potentiometric determination of iodide ion. The first, involves preparation and application of iron(II) bathophenanthroline tetraiodoplumbate complex ([Fe(bphen)3][PbI4]), as a sensitive and selective electroactive sensing material in a potentiometric electrode for iodide determination. The second is the use of a nano-sized poly(aniline-co-thiophene) (PANI-co-PT) as a solid-contact material in a planar miniaturized configuration. The SPE displays a Nernstian response for iodide ion with a calibration slope of −58.81 ± 0.69 mV/decade (R2 = 0.9998) over a wide concentration range (9.17 × 10−7–6.94 × 10−3 mol/L), low detection limit (6.09 × 10−7 mol/L), rapid response time (5.0 ± 1.0 s) and long-life span (75 ± 3.0 d). The use of PANI-co-PT solid-contact layer significantly improves the ion-to-electron transduction, eliminates the formation of undesired thin water layer between the sensing membrane and the conducting substrate, prevents membrane delamination, enhances potential stability with a significantly reduced potential drift (8.32 ± 0.12 µV/min) and displays high redox capacitance (2.560 ± 0.040 mF). Water contact angle measurements confirm the increased hydrophobicity of the modified membrane electrode (from 44 ± 0.8° to 93 ± 1.4°) and demonstrate the membrane ability to repel moisture and further stabilize the sensor response. The proposed sensor is successfully integrated into a flow injection analysis (FIA) system to enable real-time and continuous iodide monitoring with high precision, high sample throughput and applicability for quality control of pharmaceuticals and environmental monitoring.