Ultrasensitive Electrochemical Detection of Cr(VI) in the Air of Workplace Using the Bismuth Film Modified Electrode

The rapid determination of Cr(VI) in workplace air can provide technical support for daily monitoring of occupational hazard factors in enterprises. In this paper, a bismuth film/carboxylated multi-walled carbon nanotube modified glassy carbon electrode (Bi/CMWCNTs/GCE) electrochemical sensor had been used to establish a new method for detection of Cr(VI) in workplace air. Carboxylated multicycle carbon nanotubes (CMWCNTs) were modified onto glassy carbon electrode (GCE), and bismuth (Bi) film was precoated on the modified electrode by electrodeposition. The morphology and electrochemical properties of Bi/CMWCNTs modified electrodes were characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV), respectively. The results showed that the formation of stable bismuth films and sensor’s high sensitivity were due to CMWCNTs. The differential pulse stripping voltammetry (DPSV) response of Cr(VI) at Bi/CMWCNTs modified electrode outcomes with a low detection limit of 0.18 μg/L and wider linear 0.50 ~ 25.0 μg/L. In comparison to standard spectrophotometry, the newly designed electrochemical sensor had exhibited more sensitive, convenient, and environmentally friendly, which was satisfactory in analytical application to real air samples. Therefore, the Bi/CMWCNTs/GCE electrochemical sensor has the potential applications in the rapid detection of Cr(VI) in workplace air. Graphical abstract