Article

The acid dissociation constants for alternariol monomethyl ether (AME), altertoxin-I (ATX-I), and alternariol (AOH), three of the Alternaria alternata genus mycotoxins, are estimated through conventional UV-VIS spectroscopic studies at different pH values. Experimental variations of absorbance as a function of pH at a given wavelength were fitted by using the exact equations that describe the systems studied. Good agreement between the experimental absorbance vs. pH plots and the curves generated by the fitting process was found. A comparison between the acidic constants for the first step of dissociation of these mycotoxins and the value for the acidic constant of phenol is discussed by assuming that phenolic structures are responsible for the acidity of these mycotoxins.Key words: mycotoxins, alternariol monomethyl ether, altertoxin-I, alternariol, acidic constants.