| Analytical methods for quantifying mycotoxins, masked mycotoxins, and a Fusarium graminearum pigment have been developed. The objectives of the study were as follows: (1) To develop a new liquid chromatography-ultraviolet-mass spectrometry (LC-UV-MS) method to quantify deoxynivalenol (DON), DON-3-glucoside, and a Fusarium pigment in wheat samples, including evaluation of the extraction protocols to optimize the analysis, (2) To analyze zearalenone (ZEN), alpha-zearalenol (ZOL) glucoside, and beta-ZOL glucoside in wheat using a new LC-UV-MS method and laboratory-prepared silica cleanup columns, and (3) To produce, purify, and characterize the F. graminearum pigment. Using the LC-UV-MS methods, common mycotoxins DON and ZEN were found in wheat samples, along with their conjugates, at concentrations above recommended levels. In randomly selected wheat samples, the average concentrations of DON (1.4 +/- 2.3 mug/g) were significantly different (p < 0.05) than DON-3-glucoside (0.2 +/- 1.0 mug/g) while the pigment (148 +/- 247.84 mug/g) was significantly (p < 0.05) greater than both DON and DON-3-glucoside. For samples previously known to contain DON, the average levels of 3.4 +/- 4 mug/g of DON, 3.8 +/- 8.26 mug/g of DON-3-glucoside, and 0.31 +/- 3.71 g/kg of pigment were found. In randomly selected wheat samples (n = 51), the concentration of ZEN (0.34 +/- 1.47 mug/g) was not significantly different than alpha-ZOL glucoside (0.17 +/- 0.91 mug/g, p > 0.05) and beta-ZOL glucoside (0.06 +/- 0.27 mug/g, p > 0.05). The concentrations of alpha- and beta-ZOL glucoside were not significantly different (p > 0.05). Silica cleanup columns were suitable for purifying ZEN and ZOL glucosides from the wheat samples. Following successful purification of the pigment produced in culture, two major pigment components, E- and Z-Octadec-3-enoic acid 3-(4-heptanoyloxy-but-2-enoyloxy)-2-hydroxy-propyl ester, were characterized for the first time. |
