title: Determination of N-nitroso derivatives of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in soils by pressurized liquid extraction and liquid chromatography-electrospray ionization mass spectrometry.
abstract: To aid in the evaluation of the potential toxicity of N-nitroso derivatives of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), we describe a pressurized liquid extraction (PLE) followed by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) method for determination of RDX and its N-nitroso derivatives: hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX) in soils. Sandy loam soil was spiked with RDX and its N-nitroso derivatives (MNX, DNX, and TNX). Acetonitrile was used as the PLE extraction solvent at 100 degrees C and 1500 psi for 15 min. Florisil was used to cleanup extracts following PLE. Instrumental analysis employed LC-ESI-MS, in which 1mM acetic acid was added to the mobile phase to facilitate formation of acetate adduct ions [M+CH(3)COO](-). The method detection limits (MDLs) for RDX, MNX, DNX, and TNX were 1.46, 1.46, 1.69, and 1.93 ng/g, respectively. High recovery (91.1-108.3%), good precision (RSD: 3.2-12.4%), and reproducibility were achieved. This method proved effective and was applied to monitor the reductive biotransformation of MNX in soils with the presence of earthworms (Eisenia fetida).
authors.affiliation: The Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, TX 79409-1163, USA. xiaoping.pan@tiehh.ttu.edu
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Pan
authors.forename: Baohong
authors.initials: B
authors.lastname: Zhang
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Cox
authors.forename: Todd A
authors.initials: TA
authors.lastname: Anderson
authors.forename: George P
authors.initials: GP
authors.lastname: Cobb
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D009603:Nitroso Compounds / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012989:Soil Pollutants / Q000032:analysis*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014227:Triazines / Q000737:chemistry*
chemical_list: D009603:Nitroso Compounds; D012989:Soil Pollutants; D014227:Triazines; C009160:cyclonite