Rapid detection of ricin in milk using immunomagnetic separation combined with surface-enhanced Raman spectroscopy.

UNLABELLED: Ricin is a potential bioterrisiom agent. There is a critical need for a method that can rapidly and simply detect ricin and other bioterrisiom agents in complex food matrices such as milk. In this study, we demonstrated a rapid method that combined immunomagnetic separation (IMS) and surface-enhanced Raman spectroscopy (SERS) to detect ricin in whole milk. IMS was used to specifically capture the ricin out of the milk. Then, SERS was applied to analyze the IMS eluate mixed with silver dendrite nanosubstrates. This approach facilitated detection and quantification down to 4 μg/mL ricin in milk within 20 min, based on the results of principal component analysis and partial least squares analysis. The feasibility of using a portable Raman instrument shows great promise for on-site detection in a processing facility. PRACTICAL APPLICATION: The method described in this manuscript that combined IMS and SERS could be used for rapid detection of ricin and other protein toxins in complex food matrices such as milk within 20 min. The use of a portable Raman could facilitate the on-site detection in a processing facility.