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.
Cho
Chung Y
CY
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
Keener
William K
WK
Garber
Eric A E
EA
D055664:Electrochemical Techniques / Q000379:methods*; D005453:Fluorescence; D005504:Food Analysis / Q000379:methods*; D005506:Food Contamination / Q000032:analysis*; D012276:Ricin / Q000737:chemistry*
D012276:Ricin