An electrospray ionization tandem mass spectrometric (ESI-MS-MS) method has been developed for the determination of cyanide (CN(-)) in blood. Five microliters of blood was hemolyzed with 50 ìL of water, then 5 ìL 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 NaAuCl(4) to produce dicyanogold, Au(CN)(2)(-), that was extracted with 75 ìL of methyl isobutyl ketone. Ten microliters of the extract was injected directly into an ESI-MS-MS instrument and quantification of CN(-) was performed by selected reaction monitoring of the product ion CN(-) at m/z 26, derived from the precursor ion Au(CN)(2)(-) at m/z 249. CN(-) could be measured in the quantification range of 2.60 to 260 ìg/L with the limit of detection at 0.56 ìg/L in blood. This method was applied to the analysis of clinical samples and the concentrations of CN(-) in the blood were as follows: 7.13 ± 2.41 ìg/L for six healthy non-smokers, 3.08 ± 1.12 ìg/L for six CO gas victims, 730 ± 867 ìg for 21 house fire victims, and 3,030 ± 97 ìg/L for a victim who ingested NaCN. The increase of CN(-) in the blood of a victim who ingested NaN(3) was confirmed using MS-MS for the first time, and the concentrations of CN(-) in the blood, gastric content and urine were 78.5 ± 5.5, 11.8 ± 0.5, and 11.4 ± 0.8 ìg/L, respectively.
Carbon Monoxide Poisoning Case-Control Studies