Potentiometric detection of chromium (III) on the carbon fiber electrode modified by n-hexyl calix[4]resorcinarene

This study was carried out to develop the application of modified carbon fiber electrode in environmental detection, by which chromium (III) ion in water could be electrochemically detected. The modified carbon fiber electrode manifested a linear response within the range of 1.9 × 10−6–4.6 × 10−4 mol L−1 (R = 0.9939) and the detection limit was 7.9 × 10−7 mol L−1. The effect factors were studied to reveal the optimal conditions in the detection of chromium (III) in water, such as pH of total ionic strength adjustment buffer, the concentration of calix[4]resorcinarene, sweep cycles, and so on. The modified carbon fiber electrode, the diameter of which was about 7 μm, was characterized by field emission scanning electron microscopy and electrochemical impedance spectroscopy. Also, the proper mechanism was discussed. The identification of chromium (III) was mainly attributed to the cavity of the calix[4]resorcinarene that the chromium (III) ion could enter into the inner of calix[4]resorcinarene because of the particular structure of calix[4]resorcinarene.