Simultaneous Determination of RDX and HMX in Rat Plasma by LC-MS/MS and its Applications

Abstract

Background: 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) can cause serious toxicity problems in humans and animals, but direct analyses of RDX and HMX in biological samples are very limited. A rapid and efficient liquid chromatography-electrospray quadrupole linear ion trap mass spectrometry (LC-MS/MS) method suitable for the simultaneous determination of RDX and HMX in rat plasma after intravenous administration of two nitramine compound mixed solutions has been developed.Methods: Plasma samples were pretreated with one-step protein precipitation, the plasma consumption is as low as 100 μl. RDX, HMX, and internal standard mycophenolic acid were eluted for 8.0 min on a reversed-phase C18 analytical column with a water/acetonitrile mixture as the mobile phase. An electrospray ionization (ESI) source was applied and operated in negative ion mode. The optimized mass transition ion pairs (m/z) monitored for RDX, HMX, and internal standard mycophenolic acid were m/z 284.1→61.7, m/z 331.0→108.8, and m/z 319.2→191.1, respectively.Results: The detection ranges of both RDX and HMX in plasma were 5.00–200.00 ng⋅ml−1 with an LOD of 1.00 ng⋅ml−1. The extraction recoveries of RDX and HMX were 60.04 ± 4.18% and 79.57 ± 3.35%, respectively. The precision and accuracy met the requirements, and the method was stable under all tested conditions.Conclusion: The present method is miniaturized, effective, portable, rapid and can be easily used for simultaneous quantification of RDX and HMX in rat plasma.

Selectivity of Explosives Analysis with Ambient Ionization Single Quadrupole Mass Spectrometry: Implications for Trace Detection

“…For paper spray, it is noted that the ion at m / z 284, which can be attributed to [M+NO 3 ] − is more abundant than the chloride adducts, which further supports the finding of Costa et al The spray solvent used for paper spray contained both ammonium nitrate and ammonium chloride, while for ESI only ammonium chloride was used. It has previously been reported that formation of nitrate adducts is possible when using ESI without the presence of additives for the analysis of RDX and may be generated due to impurities within the solvents …”

“…It has previously been reported that formation of nitrate adducts is possible when using ESI without the presence of additives for the analysis of RDX and may be generated due to impurities within the solvents. 62 For ASAP (using air as the heated gas), TDCD, and DART, the nitrite ion [M + NO 2 ] − at m/z 268 is the most abundant and could be forming due to decomposition of RDX producing an NO 2 − fragment or from the nitrite present in the atmosphere. An ion at m/z 267 is also detected by TDCD and DART, which has been assigned as [M + NO 2 − H] − by several studies.…”