Application of deadenylase electrochemiluminescence assay for ricin to foods in a plate format.
A recently developed bead-based deadenylase electrochemiluminescence assay for ricin is simple and sensitive in its ability to detect ricin, based on the catalytic activity of the toxin subunit, ricin A chain. The assay was modified to work in a 96-well plate format and evaluated by using juice samples. The plate-based assay, unlike the bead-based assay, includes wash steps that enable the removal of food particles. These steps minimize matrix effects and improve the signal-to-noise ratios and limits of detection (LOD). The LOD values for ricin in apple juice, vegetable juice, and citrate buffer by using the bead-based assay were 0.4, 1, and 0.1 microg/ml, respectively. In contrast, the LOD values for ricin by using the plate-based assay were 0.04, 0.1, and 0.04 microg/ml in apple juice, vegetable juice, and citrate buffer, respectively. The plate-based assay displayed three- to 10-fold lower LOD values than did the bead-based assay. Signal-to-noise ratios for the plate-based assay were comparable to those for the bead-based assay for ricin in citrate buffer, but 2- to 4.5-fold higher when the plate-based assay was used for analysis of juice samples.
Office of Regulatory Science, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, 5100 Paint Branch Parkway, College Park, Maryland 20740, USA. Chung.Cho@fda.hhs.gov
Chung Y
CY
Cho
William K
WK
Keener
Eric A E
EA
Garber
D055664:Electrochemical Techniques / Q000379:methods*; D005453:Fluorescence; D005504:Food Analysis / Q000379:methods*; D005506:Food Contamination / Q000032:analysis*; D012276:Ricin / Q000737:chemistry*
D012276:Ricin