The C12 column yielded two different methods for peanut allergen
detection. Ara h 1 and Ara h 3 were detected at 16.3 and 16.3–
17.4 min, respectively by method A, and Ara h 2 was detected at
26–32 min using method F. A major drawback of the C12 column
was that Ara h 1 and Ara h 3 could not be detected at 220 nm
due to a strong base line drift. In contrast Ara h 2 showed greater
absorbance and better resolution at 220 nm compared to 280 nm.
The C18 column was able to overcome the drawbacks of the C12 column
and the goal of developing a single method to detect all of the
three peanut allergens was achieved.
Method E was chosen as the most optimal method for allergen
analysis. The use of method E increased sensitivity (absorbance),
resolution between allergen peaks, and shortened retention time for allergens. Ara h 1 and Ara h 2 eluted as individual peaks at 18.6
and 14.4 min, respectively, and Ara h 3 elutes as a set of three
peaks ranging from 19.5 to 20.2 min. The methods were very
repeatable from sample to sample and from day to day.
Acknowledgements
We would like to thank Ms. Hsiaopo Cheng for her invaluable
technical support. Financial assistance from USDA and Southern
California Institute of Food Technologists (SCIFT) section is greatly
appreciated.