determination of cyanide in blood by electrospray ionization tandem mass spectrometry after direct injection of dicyanogold an electrospray ionization tandem mass spectrometric esimsms method has been developed for the determination of cyanide cn in blood five microliters of blood was hemolyzed with 50 l of water then 5 l of 1 m tetramethylammonium hydroxide solution was added to raise the ph of the hemolysate and to liberate cn from methemoglobin cn was then reacted with naaucl4 to produce dicyanogold aucn2 that was extracted with 75 l of methyl isobutyl ketone ten microliters of the extract was injected directly into an esimsms instrument and quantification of cn was performed by selected reaction monitoring of the product ion cn at mz 26 derived from the precursor ion aucn2 at mz 249 cn could be measured in the quantification range of 260 to 260 gl with the limit of detection at 056 gl in blood this method was applied to the analysis of clinical samples and the concentrations of cn in the blood were as follows 713241 gl for six healthy nonsmokers 308112 gl for six co gas victims 730867 g for 21 house fire victims and 303097 gl for a victim who ingested nacn the increase of cn in the blood of a victim who ingested nan3 was confirmed using msms for the first time and the concentrations of cn in the blood gastric content and urine were 78555 11805 and 11408 gl respectively