Novel barium hexaferrite based highly selective and stable trace ammonia sensor for detection of renal disease by exhaled breath analysis

Exhaled human breath bears the fingerprints of multifarious pathophysiological conditions, and diseases. In this paper we report for the first time a highly sensitive, selective, and stable barium hexaferrite based sensor for the detection of trace ammonia vapor in exhaled human breath, the biomarker for renal diseases. Barium hexaferrite nanoparticles were synthesized by a facile solid-state reaction route. The as prepared nanopowder and the sensor film were well characterized by using XRD, FESEM, TEM, EDX, XPS, BET, and I-V measurements. The fabricated sensor delineates p-type behavior and the capability to detect ammonia down to 0.2 ppm with reasonably high response of ∼1.46 folds. Further, the sensor showed remarkable response of ∼2.34 folds towards 1 ppm ammonia. The sensor is practically insensitive towards similar concentrations of other major interfering breath volatiles, viz. acetone, ethanol, and saturated moisture. Also, the sensor exhibited fast response (∼2.88 s), and recovery (∼39.4 s) times ensuring real time breath analysis. Finally, long-term stability of the sensor for more than three months renders it suitable for commercial applications.