Development and application of procedures for the highly sensitive quantification of cyclosarin enantiomers in hemolysed swine blood samples

The present study was initiated to develop a sensitive method for the analysis of cyclosarin (O-cyclohexyl methylphosphonofluoridate, GF) enantiomers in biological samples utilizing classical configurations of GC–MS and automated solid phase extraction. To achieve this goal, a specific procedure had to be developed to extract cyclosarin from swine blood samples thereby stabilising and minimising the racemisation/deracemisation of its enantiomers. The chiral stationary phase was GAMMA DEX™ (gamma cyclodextrin), on which GF and deuterated GF enantiomers were baseline-resolved. The limit of detection was 1 pg for (−)-GF with GC–EI-MS and 5 pg for (+)-GF with GC–NCI-MS. The absolute recovery of the overall procedure for sample preparation was 85%. After an intravenous infusion of a supralethal dose of GF in anaesthetised swine only (−)-GF could be quantified, (+)-GF was not detected.