title: Determination of azide in gastric fluid and urine by flow-injection electrospray ionization tandem mass spectrometry.
abstract: A rapid method was developed to identify and quantify the azide ion (N(3)(-)) in gastric fluid and urine. N(3)(-) in diluted biological fluids was reacted with NaAuCl(4) to produce Au(N(3))(2)(-), which was extracted with octanol. Five microliters of the extract were flow-injected into an electrospray ionization tandem mass spectrometric instrument. Quantification of N(3)(-) was performed by selected reaction monitoring of the product ion Au(N)(N(3))(-) at m/z 253, which was derived from the precursor ion Au(N(3))(2)(-) at m/z 281, using 50 μL of aqueous solution within 10 min. This method was found to be linear up to 10(-5) M, to have a limit of quantification of 10(-7) M, a limit of detection of 3.0 × 10(-8) M, and a coefficient of variation of ≦10% at 10(-7) M. In the case of urine, 50 μL of urine were spiked with N(3)(-), this was diluted 10-fold and passed through 1 mL of a resin, and finally diluted to 100-fold of the original. This method was linear up to 10(-3) M, had a limit of quantification of 10(-5) M, a limit of detection of 3.0 × 10(-6) M, and coefficient of variation of ≦8.8% for an original urine concentration of 10(-5) M. The practical applicability of this method was checked by diluting 1 μL of a suspected suicide victim's gastric fluid 20,000-fold and 1 μL of the victim's urine 5,000-fold and then measuring the N(3)(-) levels. These levels were found to be (7.5 ± 1.0) × 10(-2) M and (3.2 ± 0.4) × 10(-3) M, respectively.
authors.affiliation: Department of Legal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu 431-3192, Japan. kminakat@hama-med.ac.jp
authors.forename: Kayoko
authors.initials: K
authors.lastname: Minakata
authors.forename: Hideki
authors.initials: H
authors.lastname: Nozawa
authors.forename: Itaru
authors.initials: I
authors.lastname: Yamagishi
authors.forename: Kunio
authors.initials: K
authors.lastname: Gonmori
authors.forename: Koutaro
authors.initials: K
authors.lastname: Hasegawa
authors.forename: Masako
authors.initials: M
authors.lastname: Suzuki
authors.forename: Kanako
authors.initials: K
authors.lastname: Watanabe
authors.forename: Osamu
authors.initials: O
authors.lastname: Suzuki
mesh_terms: D001386:Azides / Q000032:analysis* / Q000652:urine; D017022:Flow Injection Analysis; D005750:Gastric Juice / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D008297:Male; D008875:Middle Aged; D012015:Reference Standards; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013405:Suicide; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D001386:Azides