Determination of cyanide, in urine and gastric content, by electrospray ionization tandem mass spectrometry after direct flow injection of dicyanogold.

A rapid and sensitive electrospray ionization tandem mass spectrometric (ESI-MS-MS) procedure was developed for the determination of cyanide (CN(-)). CN(-) in biological fluids was reacted with NaAuCl(4) to produce dicyanogold, Au(CN)(2)(-), which was extracted with methyl isobutyl ketone (MIBK). One microliter of the extract was injected directly into an ESI-MS-MS instrument. Quantification of CN(-) was performed by selected reaction monitoring of the product ion CN(-) at m/z 26 that derived from precursor ion Au(CN)(2)(-) at m/z 249. CN(-) could be measured in the quantification range of 10(-7) to 5x10(-5) M with the limit of detection at 4x10(-8) M using 10 microL of urine within 10 min. A victim's urine and gastric content were diluted with water to 4-fold and 500-fold and measured, respectively.