Fluorescence quenching of benzo[k]fluoranthene in poly(vinyl alcohol) film: a possible optical sensor for nitro aromatic compounds

Benzo[k]fluoranthene (BkF) is a condensed multi-ring compounds with high fluorescence quantum yield and Stokes’ shift. Nitro aromatic compounds (NACs) are known to be good electron acceptors and quenchers. The fluorescence quenching of benzo[k]fluoranthene in poly(vinyl alcohol) film by different NACs, e.g. nitrobenzene, m-dinitrobenzene, o-nitrotoluene, m-nitrotoluene, p-nitrobromobenzene, o-nitroaniline, p-nitrophenol, etc. has been studied. The BkF film shows a strong quenching in the NACs concentration range from 1×10−4 to 1×10−3 M. The Stern–Volmer plots for NACs are found to be non-linear, but regular in this concentration range, which can be used for estimation of these compounds. The typical response time of the sensing film is found to be 2–10 s. The sensor film also shows minimal interference from different organic molecules and has good reversibility and reproducibility. The sensor gives a sensitivity of 1×10−5 M for p-nitrophenol.