Quantification of Ricinine and Abrine in Human Plasma by HPLC-MS-MS: Biomarkers of Exposure to Ricin and Abrin

Ricin and abrin are toxic ribosome-inactivating proteins found in plants. Exposure to these toxins can be detected using the biomarkers ricinine and abrine, which are present in the same plant sources as the toxins. The concentration of the biomarkers in urine and blood will be dependent upon the purification of abrin or ricin, the route of exposure, and the length of time between exposure and sample collection. Here, we present the first diagnostic assay for the simultaneous quantification of both ricinine and abrine in blood matrices. Furthermore, this is the first-ever method for the detection of abrine in blood products. Samples were processed by isotope-dilution, solid-phase extraction, protein precipitation and quantification by HPLC-MS-MS. This analytical method detects abrine from 5.00 to 500 ng/mL and ricinine from 0.300 to 300 ng/mL with coefficients of determination of 0.996 ± 0.003 and 0.998 ± 0.002 (n = 22), respectively. Quality control material accuracy was determined to have