Criteria for determining purity of Fusarium mycotoxins

Physical and chemical properties that may be used to determine the purity of several Fusarium mycotoxins have been investigated. A combination of analytical procedures, which include high performance thin-layer chromatography (HPTLC), liquid chromatography (LC), gas chromatography (GC), gas chromatography/mass spectrometry (GC/MS), ultraviolet spectrometry (UV), and nuclear magnetic resonance (NMR) spectrometry have been used to examine mycotoxin standards obtained from commercial sources and from laboratory fermentations. Results of this investigation indicate that commercially available standards are greater than 90% pure, but the label weight of purchased reference standards in individual containers should be verified. Mycotoxin standards, determined to be greater than 98% pure by HPTLC, LC, and GC/MS, were examined by UV spectrometry and the coefficients of extinction were determined. An interlaboratory study, involving 5 collaborators who determined coefficients of extinction (in methanol) for identical samples, gave the following results: alpha-zearalenol (lambda 236 = 28 538 +/- 558); beta-zearalenol (lambda 238 = 24 963 +/- 747); deoxynivalenol (lambda 219 = 6395 +/- 349, lot 1), (6020 +/- 228, lot 2); and T-2 toxin (lambda 202 = 3681 +/- 255). UV maxima and coefficients of extinction are also reported for HT-2 toxin (lambda 202 = 1959), diacetoxyscirpenol (lambda 203 = 2487), neosolaniol (lambda 203 = 2644), nivalenol (lambda 220 = 5142), and fusarenon-X (lambda 217 = 5997).