Electrochemical detection of nitrate with carbon nanofibers and copper co-modified carbon fiber electrodes

Obvious air pollutants are both environmental and health hazards, which is likely to cause respiratory problems in infants and the elderly. Airborne nitrates are a significant part of water-soluble ions in air pollutants. The detection of these nitrate ions would go a long way to help manage and control such ions in air pollutants and their disastrous effects. A critical challenge in the detection of nitrate is the uncontrollable concentration and signal overlapping with other ions. This study aimed at detection of nitrate ion using carbon fibers microelectrodes. A novel copper/carbon nanofibers/carbon fiber microelectrode (Cu/CNFs/CFE) was designed and used to detect nitrates in a simple, inexpensive and facile approach. The prepared Cu/CNFs/CFE has shown an increased sensitivity and a lower limit of detection for nitrate compared to bare CFE. This increase in sensitivity is due to the increased electrode surface area with a Cu/CNFs coating and more mass transport channels with superior electrocatalytic abilities. Under optimal experimental conditions, the Cu/CNFs/CFE demonstrated the detection limit of nitrate was 0.8 μM (S/N = 3) and linear range was 5 μM–8000 μM. Finally, it's pointed out the nitrate content that four air pollutant samples obtained from the cities of Yuci and Taiyuan in Shanxi province of China.