Application of a new analytical method using gas chromatography and gas chromatography–mass spectrometry for the azide ion to human blood and urine samples of an actual case

We have established a practical and reliable method to identify and quantify the azide ion in human whole blood and human urine by transforming the ion into pentafluorobenzyl azide (PFBN3). PFBN3 was simply derived from a reaction of the ion with an excess amount of pentafluorobenzyl bromide (PFBBr). The excess amount of PFBBr was removed from the products by its reaction with sodium thiosulfate. PFBN3 in the sample was detected in high sensitivity by gas chromatography with nitrogen–phosphorus detector (GC–NPD) and gas chromatography–mass spectrometry (GC–MS). The lower detection limits of the ion by GC–NPD were 5 ng/ml for human whole blood sample and 0.5 ng/ml for human urine sample at S/N=3. On the other hand, they were 100 ng/ml for human whole blood sample and 10 ng/ml for human urine sample by the full-scan mode of GC–MS. The analytical method was applied to identification and quantification of the ion in the actual whole blood and urine samples of the victims in an actual criminal case.