Printed Flexible Carbon Black-Based Sensor for Nitrite Detection in Medical Applications

This work presents a novel printed and flexible sensor for detecting nitrite (NO
2
^-
) using a hybrid nanocomposite composed of carbon black (CB), polyvinyl butyral (PVB), and 4-aminophenol (AP). We prepared the NO
2
^-
sensor using a combination of simple mixed materials, and a moderate drying temperature of 40°. The sensor has two linear response ranges to NO
2
^-
from 25 μM to 1 mM and from 1 to 50 mM, with a detection limit of 25 μM at room temperature. Our results show that the sensor displays appropriate selectivity towards 50 μM of NO
2
^-
in the presence of potentially interfering anions and organic compounds that may be present in human urine. We propose that the sensing mechanism is based on the physical electrostatic interaction of NO
2
^-
molecules with AP's positively charged amine groups. This interaction results in a reduction of the electrical resistance when the sensor is exposed to NO
2
^-
anions. Our work highlights the potential of this printed sensor as a reliable and accurate tool for NO
2
^-
detection in medical applications.