Rapid analysis of ricin using hot acid digestion and MALDI-TOF mass spectrometry.

Ricin is a protein toxin of considerable interest in forensics. A novel strategy is reported here for rapid detection of ricin based on microwave-assisted hot acid digestion and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. Ricin samples are subjected to aspartate-selective hydrolysis, and biomarker peptide products are characterized by mass spectrometry. Spectra are obtained using post source decay and searched against a protein database. Several advantages are offered by chemical hydrolysis, relative to enzymatic hydrolysis, notably speed, robustness, and the production of heavier biomarkers. Agglutinin contamination is reliably recognized, as is the disulfide bond strongly characteristic of ricin.