Determination of cyanide in blood by electrospray ionization tandem mass spectrometry after direct injection of dicyanogold

摘要

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 μL of water, then 5 μL 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 μL 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 μg/L with the limit of detection at 0.56 μg/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 μg/L for six healthy non-smokers, 3.08∈±∈1.12 μg/L for six CO gas victims, 730∈±∈867 μg for 21 house fire victims, and 3,030∈±∈97 μg/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 μg/L, respectively.