**3. Conclusions**

Two mAbs that recognize CTV were developed and applied in CI-ELISAs to the detection of CTV and iso-CTV. With CTV in bu ffer, the assays were of good sensitivity, with IC50s of 11 ng/mL (mAb 2-2) and 18 ng/mL (mAb 2-4). Assays based upon both mAbs were relatively tolerant to methanol and acetonitrile. For best results, it is recommended to keep the methanol concentration at or below 20% and the acetonitrile concentration at or below 10%. One of the mAbs (2-4) was applied to the detection of CTV and iso-CTV in spiked rice. Using matrix-matched calibration and a mixed CTV/iso-CTV standard, the dynamic range was equivalent to 0.23 to 2.22 mg/kg in rice. Recoveries were excellent, averaging 97 ± 10% over the range of 0.36 to 7.23 mg/kg. The developed mAbs and CI-ELISAs will be useful for the screening of CTV and iso-CTV in white rice. In addition, it was observed that both mAbs significantly enhanced the fluorescence of CTV, a phenomenon that may be useful in future e fforts to determine the a ffinity of the antibodies for the toxin.

#### **4. Materials and Methods**
