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Development of a Multi-Residue Method for Mycotoxin Analysis in Feeds and Grains. Midwest AOAC, St. Paul, MN, June 10, 2003. Introduction and background. Two basic methods can screen for or quantitate 5 classes of toxins Multi-residue method needed for convenience and increased sensitivity
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Development of a Multi-Residue Method for Mycotoxin Analysis in Feeds and Grains Midwest AOAC, St. Paul, MN, June 10, 2003
Introduction and background • Two basic methods can screen for or quantitate 5 classes of toxins • Multi-residue method needed for convenience and increased sensitivity • The ruggedness of separation and detection of the mycotoxins has been well-established • Easy to use with current post-column system • Uses a reliable and affordable sample cleanup for feeds, grains
Method 1: Trichothecene (DON) Aflatoxins (incl. M1 & M2) Zearalenone Ochratoxin A Method 2: Trichothecene (DON) Aflatoxins (incl. M1 & M2) Fumonisins (FB1, FB2, FB3) 2 Methods to Analyze 5 classes of Mycotoxins
Post Column Set Up • PCX 5200 with duplex pump, 2 ml reactor • Simplex pump will also be sufficient, but requires more conversion time • PCX Control software • Photochemical reactor (Needed for Aflatoxins Only) • UV detector • Fluorescence detector
Flow Paths of Post-Column Systems Method 1 Method 2
Aflatoxin, DON, Zearalenone ACN : H2O (84:16) 100 mL Add 25 g of ground sample C18 : Alumina (1:1) Fill column with 1.5g Filter 6 mL of extract Inject Note: for increased DON response, evaporate and reconstitute in MeOH Sample Preparation and Cleanup Method 1
Conclusions for Method 1 • Sample prep works well for most samples • Certain matrices have interferences with portions of the chromatogram • Good sensitivity on the detection. Can see well below recommended amounts • Method can easily match the allowed limits
Sample Preparation and Cleanup, Method 2 • DON, Aflatoxins, Fumonisins • MeOH : H2O (80:20) 100 mL • Add 50 g of ground sample • C18 only • Fill column with 1.5 g • Filter 6 mL of extract • Note: No alumina – the Fumonisins stick to the alumina
Conclusions for Method 2 • Reliable extraction for Fumonisins requires more investigation • Some interferences with Aflatoxins as with Method 1 • Can easily detect below allowed limits
Future work • Improve sample preparation and cleanup for Fumonisins • Examine interferences in some samples • Try reconstituting in MeOH • Investigate recoveries
Acknowledgements • Nancy Thiex, South Dakota State University • Beth Tacke, North Dakota State University • Maria Ofitserova, Ph.D., Pickering Laboratories, Inc. • Darsa Siantar, Ph.D., ATTB
Questions and Discussion Sareeta Nerkar & Maria Ofitserova