title: Development of antibody-mediated extraction followed by GC/MS (antibody/GC/MS) and its application to iloprost determination in plasma.
abstract: A new analytical principle has been developed combining the features of both radioimmunoassay and GC/MS. Its application in eicosanoid analysis was tested with the prostacyclin analogue, iloprost. The iloprost antibody, generally employed in RIA measurements, was coupled to Sepharose 4B and used as stationary phase for extraction of the drug. Variations in recovery were corrected by using deuterated iloprost as an internal standard. The samples were derivatized and quantitated by negative-ion chemical ionization-mass spectrometry. Reproducibility was 2.3 % at the 50 pg/ml level and the limit of detection was 5 pg for 1 ml samples. With plasma volumes of up to 20 ml, 0.25 pg/ml could be determined. Antibody/GC/MS proved superior to radioimmunoassay due to its higher specificity and sensitivity and superior to GC/MS with conventional clean-up procedures because of a higher sample capacity.
mesh_terms: D011464:Epoprostenol / Q000032:analysis* / Q000276:immunology; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007163:Immunosorbent Techniques; D011465:Prostaglandins, Synthetic / Q000032:analysis* / Q000276:immunology; D011863:Radioimmunoassay
chemical_list: D011465:Prostaglandins, Synthetic; D011464:Epoprostenol