Volume 7 Issue 3

ABSTRACT

The aim of this work is to study the electrochemical response of dual highly selective ion detection in response to a sensor based on MPTES mediated electrochemical interdigitated dual electrode arrays. In various concentrations the performance of the sensor for Na⁺, K⁺, Ca²⁺ and Cl⁻ ions detection was investigated. For these two parameters, sensitivity and selectivity were characterized by calibration curves and peak current measurements respectively. From the calibration curves, high sensitivity of the sensor towards sodium ions was observed giving a response of 0.35 μA/ppm at sodium of 10 ppm and decreased to 0.14 μA/ppm at 500 ppm. The good linearity of the calibration curve indicates that the sensor has high sensitivity and can accurately detect sodium ions with a low concentration. The response to potassium ions varied from 0.29 μA/ppm at 10 ppm to 0.13 μA/ppm at 500. PPM, indicating lower sensitivity than sodium ions. Of the ions considered, calcium ions demonstrated the lowest sensitivity (response values decreased from 0.18 μA/ppm at 10 ppm to 0.09 μA/ppm at 500 ppm), thus, less effective detection. A moderately sensitive response for detecting chloride ions was observed, with a response of 0.40 μA/ppm at 10 ppm declining to 0.16 μA/ppm at 500 ppm. Peak currents for sodium ions ranged from 3.5 μA at 10 ppm to 70.1 μA at 500 ppm with respect to selectivity tests indicating high sensitivity (quoted from Authors). The current measurements show that response currents for potassium ions and calcium ions reached maximum values of 2.9 μA at 10 ppm and 65.2 μA at 500 ppm in the case of potassium ions, and 1.8 μA at 10 ppm and 45.8 μA at 500 ppm in the case of calcium ions. For chloride ions, peak currents of 4.0 μA and 80.0 μA were observed at concentrations of 10 ppm and 500 ppm respectively. The performance of the sensor for the sodium ions (selective), chloride ions (moderate), potassium ions (low), and calcium ions (low) is summarised in these results. Finally, the electrochemical interdigitated dual electrode array sensor catalyzed with the MPTES showed high sensitivity toward sodium ions, while only moderate performance toward chloride ions. On the other hand, it is less sensitive for potassium and calcium ions. These results highlight the use of the sensor for accurate ion detection in applications for which sodium ions are of particular interest, and indicate areas for improvement towards greater performance for other ions.

Keywords:  Interdigitated Dual Electrode Arrays (IDEA),  Self-Assembled Monolayers (SAMs),  Surface Modification,  Bio-electrochemical Sensors,  Trace Analysis.