Extraction and determination of trace amounts of energetic compounds in blood by gas chromatography with electron capture detection (GC/ECD)

This paper describes an efficient and sensitive method for determining five energetic compounds at trace levels (ng/mL) in blood by gas chromatography with electron capture detection (GC/ECD). For seven test concentrations (1-1250 ng/mL), the average recoveries (%) were 104 ± 16, 108 ± 22, 105 ± 14, 100 ± 22 and 108 ± 16 for hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX), hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), hexahydro-1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and 2,4,6-trinitrotoluene (TNT) (n = 84), respectively. Analysis of DNX and RDX produced lower precision than other energetic compounds. Acetonitrile extracts of blood samples should be analyzed immediately as the test compounds can transform into unknown compounds, which lowered the recovery by 0-45% within 10 days at room temperature (∼20 °C). Maintaining sample extracts at 4 °C decreased loss of test compounds. The method described herein was validated by different analysis teams on different days. Two-way ANOVA indicated that there was no significant difference between analysis teams or days of analysis. The method was successfully employed in the analysis of blood samples from a mouse dosing study involving TNX and RDX.