Effects of Solvent, pH and Ionic Strength on the Fluorescence Features of Aflatoxin B1, B2, G1 and G2

The effects of environmental parameters, including solvent, pH and ionic strength on the fluorescence features of aflatoxin B1, B2, G1 and G2 were investigated. Fluorescence spectral characteristics such as fluorescence emission intensity, stokes shift and maximum emission wavelength were markedly affected by solvent type. The emission fluorescence peak of aflatoxins assessed was between 370 and 500 nm under a 360 nm excitation source. The maximum fluorescence intensities were obtained with ethanol and acetonitrile for all aflatoxins studied. The maximum displacements on emission wavelengths for aflatoxin B1, B2, G1 and G2 were obtained in methanol, dichloromethane, chloroform and acetonitrile, respectively. The maximum signal intensity was obtained in relatively low acidity values. Also, the study of ionic strength revolved that the maximum signals are obtained at 0.1 M NaCl. This study also shows that there is no need for another fluorophore for the study of investigated aflatoxins.