The prototype application of the micro interdigitated electrode (µIDE) sensor developed for micro gas chromatography

Today, traditional e-nose systems have been replaced by gas detection systems based on micro gas chromatography(µGC). This approach, which is based on the fabrication of components at the micro scale, has the potential to improve the selectivity and sensitivity of e-nose systems. Therefore, the development of high-precision gas sensors integrated with µGC is a critical research topic. In this study, a prototype application of a micro interdigitated electrode (µIDE) gas sensor array integrated onto a µGC system made of silicon material was realized. This integration allowed for the rapid characterization of the uniquely produced µIDE sensor. Additionally, the structure of the µGC system designed with the integrated µIDE sensor has been introduced to the literature. All experimental results in this study were obtained using the µIDE sensor prototype. The fact that the prototype exhibits chemical capacitive behavior similar to that of the original silicon-based µIDE sensor, possesses comparable impedance values at the same frequency, and maintains identical electrode thickness and spacing, reinforces the validity and representativeness of the experimental measurement outcomes. The impedance of the µIDE sensor prototype is approximately 32 kΩ at a frequency of 10 MHz. An AC interface circuit was designed to measure variations in the impedance magnitude and phase angle of the µIDE sensor prototype. To reduce noise in the sensor’s gas measurement signals and to improve measurement performance, a linear Kalman filter was utilized. The gas detection sensitivities of the µIDE sensor prototype were calculated as 0.7517 Ω/ppm for NO₂ (6.7 ppm), 0.0118 Ω/ppm for acetone (3640 ppm), 0.0067 Ω/ppm for ethanol (1820 ppm), and 0.0077 Ω/ppm for chloroform (1465 ppm). This research is a pioneering study in the measurement of air pollutants such as NO₂ gas, as well as other volatile organic compound gases such as acetone, ethanol, and chloroform, using a capacitive sensor.