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The evaluation of 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) as a derivatizing reagent for
fumonisin B(1) determination. A. Chawnua, R. L. Wehling, and L. B. Bullerman. University of
Nebraska, Dept. of Food Science & Technology, Lincoln, NE 68583.
Several methods are presently used to quantify Fumonisin B(1) in
foods and feeds. HPLC procedures using derivatization of FB(1) and fluorescence detection are most
commonly used. However, derivatizing reagents currently employed produce derivatives with limited
stability. Therefore, this study was conducted to find an alternative reagent that could yield a highly
sensitive and stable fluorescent derivative. 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) was
evaluated as an alternative derivatizing reagent to o-phthalaldehyde (OPA). FB(1) was measured by
precolumn derviatization, followed by isocratic HPLC separation. Studies on derivatization conditions
indicated good derivative yields with AQC over a pH range of 8.0 to 10.0. Excitation at 250 nm, and
emission at 395 nm, were suitable wavelenths to analyze AQC-derivatized FB(1). A reversed-phase C(18)
column with a mobile phase of acetonitrile/50 mM KH(2) PO(4) (35:65) adjusted to pH 4.1 gave the best
separation. Derivatives formed with the AQC reagent were stable for more than 72 hours, whereas
OPA-derivatized FB(1) was stable only 30 min after reaction. The quantitation limits were 50 ng/g for the
AQC-derivatized FB(1), and 62.5 ng/g for OPA-derivatized FB(1). The AQC method was evaluated with
extruded corn grits containing FB(1) added before extrusion. A strong anion exchange SPE cartridge was
used to clean up the extracted sample prior to derivatization. Recoveries of AQC-derivatized and
OPA-derivatized FB(1) were 88.7% and 89.7%, with CV's of 7.71% and 8.07%, respectively.
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