A low-cost room-temperature electronic nose prototype for gas sensor characterization and simulated breath analysis

Abstract This work addresses the need for cost-effective and scalable platforms for chemiresistive gas-sensor characterization and exhaled breath (EB) analysis, as conventional laboratory instruments are often expensive and complex. A low-cost, room-temperature electronic nose (E-nose) prototype, termed the E-nose tester, was developed as a versatile platform for multichannel signal acquisition, sensor characterization, and data analysis. The system enables stable signal acquisition and reliable evaluation of key sensing parameters, including response, repeatability, and detection limit. To validate the platform, three PANI-based gas sensors (PANI, PANI/Au, and PANI/Ag) fabricated via a vapor phase polymerization (VPP) method were systematically tested. The developed platform demonstrates stable sensing performance, low detection limits, and good repeatability while maintaining substantially lower hardware cost than conventional laboratory instruments. To further demonstrate its applicability, the E-nose tester was extended to simulated EB analysis experiments using ammonia, a volatile compound frequently reported as chronic kidney disease (CKD) related breath biomarker. Simulated breath samples with different ammonia levels were analyzed using feature extraction and machine learning methods. The results demonstrated the feasibility of integrating the proposed platform with pattern-recognition workflows for simulated EB analysis scenarios. Overall, the proposed system provides a low-cost and scalable solution for chemiresistive gas-sensing research, E-nose development, and future EB analysis studies.