Preconcentration and electrochemical determination of nitropyrene at electrochemically activated glassy carbon electrodes

Polycyclic aromatic hydrocarbons substituted with one or more nitro-groups (nitro-PAHs) have been proven to be carcinogenic. This work provides the first report on the electroanalysis of nitro-PAHs using chemically modified electrodes. A representative nitro-PAH species, namely nitropyrene was readily extracted onto electrochemically pretreated glassy carbon electrodes (pGCE) from methanol solution. The nitropyrene species adsorbed on pGCE were reduced electrochemically to aminopyrene in a 6-electron process in 0.5 M H₂SO₄. Both nitropyrene and aminopyrene were found to adsorb strongly on pGCE. Experimental results showed that the peak current resulting from nitropyrene reduction was proportional to the concentration in their methanol solution for a wide dynamic range from 5 to 1500 ng/mL with a large slope of 0.0864 A Lg^-1 and a correlation coefficient of 0.999. The preconcentration and determination conditions, as well as possible interference from other PAH species, were investigated. Possible application in the determination of nitropyrene in air particulate was evaluated.