Copper ferrite inverse spinel-based highly sensitive and selective chemiresistive gas sensor for the detection of formalin adulteration in fish

The unexpected presence of food preservatives such as formalin in food can cause significant health hazards e.g., severe damage to the pulmonary and nervous system, kidney, lungs, eyes, etc. In this work, semiconducting Copper ferrite (CuFe2O4) inverse spinel nanoparticles-based gas sensor for the detection of formalin adulteration in fish has been reported. The nanopowder was synthesized by a simple sol-gel route. The nanopowder was characterized by multiple sophisticated techniques, viz., XRD, XPS, FESEM, TEM, EDS, UV-Vis spectroscopy, laser diffraction-based particle size distribution measurement, current-Voltage (I-V) measurement, infra-red imaging, and non-contact optical profilometry. The developed sensor exhibits high p-type sensitivity towards trace formalin gas (5–30 ppm), rapid response (∼2.7 s) and recovery times (∼34 s), and appreciable selectivity with respect to other gases in trace concentrations, such as acetone, ethanol etc., and saturated moisture at moderate operating temperature (260 °C). The excellent long-term stability of the sensor for at least 6 months renders it suitable for commercial applications. [Display omitted] ●Facile sol-gel synthesis of Copper Ferrite inverse spinel nanopowder.●Excellent p-type response to trace formalin with detection lower limit of ∼3 ppm.●Rapid response (∼2.7 s) and recovery times (∼34 s).●Excellent selectivity with respect to trace acetone, ethanol, and saturated moisture.●Long-term stability for at least 6 months.