Medical Aspects of Chemical Warfare (2008) - The Black Vault

Medical Aspects of Chemical WarfareDrasch et al examined urine samples for unmetabolizedsulfur mustard. Following organic extraction,thin-layer chromatography, and derivativation withgold, the extracts were analyzed using electrothermalatomic absorption spectroscopy. 85More recently, additional methods have beendeveloped for trace level analysis of TDG and TDGsulfoxidein urine. 86–89 There are a number of characteristicscommon to the methods (Table 22-7). They alluse GC in association with some form of MS analysis,use a derivatizing agent to make the analyte moreamenable to GC analysis and to increase sensitivity,and incorporate an isotopically labeled form of TDGas an internal standard. Most of the methods use asolid phase extraction cartridge for sample preparation.Some of the methods incubate the urine sampleswith glucuronidase with sulfatase activity to releaseany glucuronide-bound conjugates. Some of the methodsuse titanium trichloride in hydrochloric acid toreduce TDG-sulfoxide to TDG. The strong acid alsohydrolyzes acid-labile esters of TDG and TDG-sulfoxide(Table 22-8). Ultimately, each of the methodsconverts all target analytes into the single analyte TDGfor analysis. All of the methods have similar limits ofdetection, approximately 0.5 to 1 ng/mL. Although anassay has been developed to analyze TDG-sulfoxideseparately without a conversion to TDG, the methodis complicated by the high polarity of the analyte. 90Consequently, the more common approach is to usethe reducing agent titanium trichloride.Unfortunately, regardless of the analytical methodused, background levels have consistently been foundin urine samples obtained from nonexposed individuals.In the most extensive study of background levels,urine samples from 105 individuals were examinedfor sulfur mustard metabolites using an assay thatincorporates both a deconjugation process and a reductionstep (ie, the assay measures free and boundforms of both TDG and of TDG-sulfoxide). 89 Quantifiablebackground levels were observed in 82% of thesamples. Nearly 60% of the samples had observedlevels of TDG in the 0.5- to 2.0-ng/mL range, whileapproximately 9% had levels in the 10- to 20-ng/mLrange. When urine samples with higher backgroundTable 22-7Analysis Methods for Urine Samples to Measure Thiodiglycol or Thiodiglycoland Thiodiglycol-SulfoxideGlucuronidase TiCl 3Internal DetectionInstrumentation Derivativizing Agent SPE Cartridge Incubation Reduction Standard LimitNegative ion chemical Pentafluorobenzoyl Florisil Yes no 2H 4-TDG ~ 1 ng/mL 1ionization GC-MS chlorideElectron impact GC-MS Heptafluorobutyric None Yes no 2 H 8-TDG ~ 1 ng/mL 2anhydrideNegative ion chemical Pentafluorobenzoyl Florisil No yes 2 H 4-TDG < 1 ng/mL 3ionization GC-MS-MS chloridePositive chemical ioni- Heptafluorobutyric Oasis HLB Yes yes13C 4-TDG 0.5 ng/mL 4zation GC-MS-MS anhydride13 C 4: isotopically labeled carbon2 H 4: isotopically labeled hydrogen or deuterium2 H 8: isotopically labeled hydrogen or deuteriumGC: gas chromatographyHLB: hydrophilic-lipophilic-balancedMS: mass spectrometrySPE: solid phase extractionTDG: thiodiglycolTiCl 3: titanium trichlorideData sources: (1) Black RM, Read RW. Detection of trace levels of thiodiglycol in blood, plasma and urine using gas chromatography-electroncapturenegative-ion chemical ionisation mass spectrometry. J Chromatogr. 1988;449:261–270. (2) Jakubowski EM, Woodard CL, MershonMM, Dolzine TW. Quantification of thiodiglycol in urine by electron ionization gas chromatography-mass spectrometry. J Chromatogr.1990;528:184–190. (3) Black RM, Read RW. Improved methodology for the detection and quantitation of urinary metabolites of sulphurmustard using gas chromatography-tandem mass spectrometry. J Chromatogr B Biomed Appl. 1995;665:97–105. (4) Boyer AE, Ash D, Barr DB,et al. Quantitation of the sulfur mustard metabolites 1,1’-sulfonylbis[2-(methylthio)ethane] and thiodiglycol in urine using isotope-dilutiongas chromatography-tandem mass spectrometry. J Anal Toxicol. 2004;28:327–332.710