Human plasma ricinine quantification by LC-HRMS after micro-solid phase elution.

A rapid, sensitive, and specific method for ricinine identification and quantification in plasma has been developed by LC-HRMS. Deuterated ricinine was used as internal standard. From 100 μL of plasma, ricinine is extracted using micro-solid phase elution, which allows a reduced extraction time, by eliminating the evaporation step. Eluate is directly injected in the LC-HRMS system. Chromatographic separation was performed using a reverse phase C18 column with a 4.5-minute gradient elution. The method was validated according to European Medicines Agency (EMA) guidelines. Linearity was verified between 0.25 and 500.0 ng/mL; the maximum precision calculated was 19.9 % for LLOQ and 9.6 % for quality control, and accuracy was within ± 5.6 % of the nominal concentrations. Selectivity, carry-over, matrix effect and stability were also verified according to EMA guidelines. The method allows the rapid and reliable identification of ricin-exposed victims in case of terrorist attacks or poisonings: 3 intoxication cases are reported.