The Experts below are selected from a list of 192 Experts worldwide ranked by ideXlab platform
Raimo A Ketola - One of the best experts on this subject based on the ideXlab platform.
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analysis of nitrogen based explosives with desorption atmospheric pressure photoionization mass spectrometry
Rapid Communications in Mass Spectrometry, 2016Co-Authors: Tiina J Kauppila, Anu Flink, J Pukkila, Raimo A KetolaAbstract:Rationale Fast methods that allow the in situ analysis of explosives from a variety of surfaces are needed in crime scene investigations and home-land security. Here, the feasibility of the ambient mass spectrometry technique desorption atmospheric pressure photoionization (DAPPI) in the analysis of the most common nitrogen-based explosives is studied. Methods DAPPI and desorption electrospray ionization (DESI) were compared in the direct analysis of trinitrotoluene (TNT), trinitrophenol (picric acid), octogen (HMX), Cyclonite (RDX), pentaerythritol tetranitrate (PETN), and nitroglycerin (NG). The effect of different additives in DAPPI dopant and in DESI spray solvent on the ionization efficiency was tested, as well as the suitability of DAPPI to detect explosives from a variety of surfaces. Results The analytes showed ions only in negative ion mode. With negative DAPPI, TNT and picric acid formed deprotonated molecules with all dopant systems, while RDX, HMX, PETN and NG were ionized by adduct formation. The formation of adducts was enhanced by addition of chloroform, formic acid, acetic acid or nitric acid to the DAPPI dopant. DAPPI was more sensitive than DESI for TNT, while DESI was more sensitive for HMX and picric acid. Conclusions DAPPI could become an important method for the direct analysis of nitroaromatics from a variety of surfaces. For compounds that are thermally labile, or that have very low vapor pressure, however, DESI is better suited. Copyright © 2016 John Wiley & Sons, Ltd.
Baohong Zhang - One of the best experts on this subject based on the ideXlab platform.
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rdx induces aberrant expression of micrornas in mouse brain and liver
Environmental Health Perspectives, 2009Co-Authors: Baohong Zhang, Xiaoping PanAbstract:Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX, also known as hexogen or Cyclonite) is a common environmental pollutant resulting from military and civil activities. According to the U.S. Department of Defense, an estimated 12,000 sites across the United States have been contaminated with explosives, including RDX. Concentrations of RDX in soils exceed thousands of milligrams per kilogram (Jenkins et al. 2006). RDX and its metabolites were also identified in water sources, including groundwater (Beller and Tiemeier 2002). Environmental contamination by RDX and its N-nitroso metabolites has raised health concerns about human and environmental exposure (Zhang et al. 2008). It has long been known that RDX exposure causes neurotoxicity, immunotoxicity, and an increased likelihood of cancers. A causal relationship has been established between seizures and acute occupational RDX exposure in humans, with results confirmed in laboratory animals (Burdette et al. 1988; Pan et al. 2007; Testud et al. 1996). One early study demonstrated that RDX exposure elevated the incidence of tumors in B6C3F1 mice (Lish et al. 1984). Based on these findings, RDX has been classified as a class C potential human carcinogen by the U.S. Environmental Protection Agency (U.S. EPA 1988). Despite evidence supporting the role of RDX as a cytotoxic agent and potential chemical carcinogen, the molecular mechanism of RDX-induced neurotoxicity and potential carcinogenesis remains unknown. Recently identified microRNAs (miRNAs) may play an important role in RDX exposure and in the process of RDX-induced tumorigenesis and neurotoxicity. miRNAs are a group of small non-protein-coding endogenous RNAs that posttranscriptionally regulate the expression of > 30% of human protein-coding genes (Lewis et al. 2005). miRNAs negatively regulate gene expression through translation inhibition, mRNA cleavage, or deadenylation/decap-mediated mRNA decay (Giraldez et al. 2006; Wu et al. 2006). These mechanisms are likely governed by the degree of complementarity between mRNAs and their targeting miRNAs (Zhang et al. 2007b). In animals, most miRNAs bind to their target mRNAs imperfectly for repressing protein translation at multiple complementary sites within the 3k untranslated regions (UTRs) (Ambros 2001), with a few exemptions at the open reading frames or 5k UTRs (Lytle et al. 2007). Many miRNAs are evolutionarily conserved in animals, from worms to humans (Pasquinelli et al. 2000), suggesting that miRNA functions are conserved from species to species. miRNAs play an important role in almost all fundamental biological and metabolic processes in eukaryotic organisms (Zhang et al. 2007b). Many recent studies have demonstrated that miRNAs regulate cancer development, including cancer invasiveness and metastasis. Most commonly occurring cancers are associated with the aberrant expression of at least one miRNA (Zhang et al. 2007a). Moreover, it has been established that specific cancers have their unique miRNA expression profiles (Lu et al. 2005), suggesting that miRNAs respond to different cancers in different ways. Thus, miRNA profiles are useful for classifying and identifying cancers. Changes in miRNA expression can regulate the cancer development cascade. A recent in vitro study showed that transient overexpression of the miRNA let-7 in A549 lung adenocarcinoma cell lines inhibited lung cancer cell proliferation (Takamizawa et al. 2004). Another study found that changes in the expression levels of a single miRNA (miR-10b) could initiate tumor invasion and metastasis (Ma et al. 2007). It is well known that many chemical toxicants and biological toxins cause different types of cancers. Although various environmental carcinogens cause DNA and chromosome damage as well as the aberrant expressions of cancer-related genes and toxicant-metabolizing enzymes, the pathogenic mechanisms of toxicant/toxin-induced cancers are unclear (de Kok et al. 2005; Myllynen et al. 2007). Because miRNAs play important roles in cancer development, and the aberrant expression of miRNAs has been observed in different cancers, we hypothesized that the exposure to a specific environmental procarcinogen, such as RDX, would induce alterations in miRNA expression, and that the altered miRNA expression contributes to carcinogenesis. To test this hypothesis, we exposed B6C3F1 mice to RDX and investigated the effect of RDX exposure on the global expression profile of miRNAs, particularly on the oncogenic, tumor-suppressing, and disease-related miRNAs. We assayed RDX-induced changes in miRNAs using microarray and quantitative real-time polymerase chain reaction (qRT-PCR) technologies. Given that miRNAs are highly conserved between mice and humans, the results would help us better understand the molecular mechanisms of RDX-related diseases, including potential carcinogenic and neurologic damages.
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extraction and analysis of trace amounts of Cyclonite rdx and its nitroso metabolites in animal liver tissue using gas chromatography with electron capture detection gc ecd
Talanta, 2005Co-Authors: Baohong Zhang, George P CobbAbstract:Abstract An efficient extraction and cleanup technique, and an instrumental detection method suitable for determination of trace amounts of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and its nitroso-metabolites in animal liver tissue were developed and validated in this paper. The method includes the extraction of explosives from liver tissue samples using accelerated solvent extraction (ASE) followed by cleanup using florisil and styrene-divinyl benzene (SDB) cartridges to remove interfering naturally endogenous compounds. The instrumental analysis was conducted using a capillary column gas chromatograph coupled with an electron capture detector (GC–ECD). High recoveries (58.9–106.8%) of RDX, 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) were achieved at all concentrations studied. RDX, MNX, and TNX gave higher recoveries than DNX at all three tested concentrations (50, 250, 1250 ng/g). Overall recoveries of RDX, MNX, DNX, and TNX from 1 g beef liver samples containing 50, 250, and 1250 ng/g were 80.1, 82.8, 68.9, and 80.4%, respectively. The optimal injection port temperature range was 160–170 °C for analysis of RDX and its nitroso-metabolites. Higher or lower temperatures than 160–170 °C decreased signal amplitudes. RDX was unstable in the liver extraction matrix; as much as 50% of RDX was degraded 10 days after extraction if keeping the liver sample extracts at room temperature. Degradation of RDX to MNX, DNX, or TNX was not detected during the sample storage, extraction, or instrument analysis processes. Other optimized extraction and GC conditions are also discussed.
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Extraction and analysis of trace amounts of Cyclonite (RDX) and its nitroso-metabolites in animal liver tissue using gas chromatography with electron capture detection (GC-ECD)
Talanta, 2005Co-Authors: Xiaoping Pan, Baohong Zhang, George P CobbAbstract:An efficient extraction and cleanup technique, and an instrumental detection method suitable for determination of trace amounts of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and its nitroso-metabolites in animal liver tissue were developed and validated in this paper. The method includes the extraction of explosives from liver tissue samples using accelerated solvent extraction (ASE) followed by cleanup using florisil and styrene-divinyl benzene (SDB) cartridges to remove interfering naturally endogenous compounds. The instrumental analysis was conducted using a capillary column gas chromatograph coupled with an electron capture detector (GC-ECD). High recoveries (58.9-106.8%) of RDX, 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) were achieved at all concentrations studied. RDX, MNX, and TNX gave higher recoveries than DNX at all three tested concentrations (50, 250, 1250 ng/g). Overall recoveries of RDX, MNX, DNX, and TNX from 1g beef liver samples containing 50, 250, and 1250 ng/g were 80.1, 82.8, 68.9, and 80.4%, respectively. The optimal injection port temperature range was 160-170 degrees C for analysis of RDX and its nitroso-metabolites. Higher or lower temperatures than 160-170 degrees C decreased signal amplitudes. RDX was unstable in the liver extraction matrix; as much as 50% of RDX was degraded 10 days after extraction if keeping the liver sample extracts at room temperature. Degradation of RDX to MNX, DNX, or TNX was not detected during the sample storage, extraction, or instrument analysis processes. Other optimized extraction and GC conditions are also discussed.
Jeongkwon Kim - One of the best experts on this subject based on the ideXlab platform.
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Characterization of RDX and HMX explosive adduct ions using ESI FT-ICR MS.
Journal of mass spectrometry : JMS, 2020Co-Authors: Jihyeon Lee, Soo Gyeong Cho, Eun Mee Goh, Min Sun Kim, Hyun Sik Kim, Yoong-kee Choe, Jeongkwon KimAbstract:Investigation of two common explosives such as Cyclonite (RDX) and cyclotetramethylenetetranitramine (HMX) using a mass spectrometer with ultrahigh resolution and accuracy has not been comprehensively performed. Here, ultrahigh mass accuracy 15-T Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) spectra were utilized to comprehensively characterize the adduct ions of RDX and HMX. Two different ionization sources such as a conventional electrospray ionization (ESI) source and a chip-based static nano-ESI source were used to investigate the adduct ions of RDX and HMX. The ESI-MS analyses of two explosives in negative ion mode provide some adduct ions of RDX and HMX even without prior addition of their corresponding anions. A total of six types of adduct ion were characterized: [M + Cl]- , [M + HCOO]- , [M + NO2 ]- , [M + CH3 COO]- , [M + NO3 ]- , and [M + C3 H5 O3 ]- , where M is either RDX or HMX. The ultrahigh accuracy of the 15-T FT-ICR MS was utilized to distinguish two closely spaced peaks representing the monoisotopic [M + NO2 ]- and second isotopic [M + HCOO]- ions, thereby enabling the discovery of a [M + NO2 ]- adduct ion in the ESI analysis of RDX or HMX. [M + NO2 ]- and [M + CH3 COO]- adduct ions were only observed when using a static nano-ESI source. It is the first report explaining the discovery of [M + NO2 ]- adduct ion in the ESI-MS analyses of RDX and HMX.
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Mass Spectrometric Analysis of Eight Common Chemical Explosives Using Ion Trap Mass Spectrometer
Bulletin of the Korean Chemical Society, 2013Co-Authors: Sehwan Park, Jihyeon Lee, Soo Gyeong Cho, Eun Mee Goh, Sungman Lee, Sung-suk Koh, Jeongkwon KimAbstract:Eight representative explosives (ammonium perchlorate (AP), ammonium nitrate (AN), trinitrotoluene (TNT), 2,4-dinitrotoluene (DNT), Cyclonite (RDX), cyclotetramethylenetetranitramine (HMX), pentaerythritol tetranitrate (PETN), and hexanitrostilbene (HNS)) were comprehensively analyzed with an ion trap mass spectrometer in negative ion mode using direct infusion electrospray ionization. MS/MS experiments were performed to generate fragment ions from the major parent ion of each explosive. Explosives in salt forms such as AP or AN provided cluster parent ions with their own anions. Explosives with an aromatic ring were observed as either [M–H] – for TNT and DNT or [M] – for HNS, while explosives without an aromatic ring such as RDX, HMX, and PETN were detected as an adduct ion with a formate anion, i.e., [M+HCOO] – . These findings provide a guideline for the rapid and accurate detection of explosives once portable MS instruments become more readily available.
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Analysis of explosives using corona discharge ionization combined with ion mobility spectrometry-mass spectrometry.
Talanta, 2013Co-Authors: Jihyeon Lee, Sehwan Park, Soo Gyeong Cho, Eun Mee Goh, Sungman Lee, Sung-suk Koh, Jeongkwon KimAbstract:Abstract Corona discharge ionization combined with ion mobility spectrometry–mass spectrometry (IMS–MS) was utilized to investigate five common explosives: Cyclonite (RDX), trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), cyclotetramethylenetetranitramine (HMX), and 2,4-dinitrotoluene (DNT). The MS scan and the selected ion IMS analyses confirmed the identities of the existing ion species and their drift times. The ions observed were RDX·NO3−, TNT−, PETN·NO3−, HMX·NO3−, and DNT−, with average drift times of 6.93 ms, 10.20 ms, 9.15 ms, 12.24 ms, 11.30 ms, and 8.89 ms, respectively. The reduced ion mobility values, determined from a standard curve calculated by linear regression of (normalized drift times)−1 versus literature K0 values, were 2.09, 1.38, 1.55, 1.15, 1.25, and 1.60 cm2 V−1 s−1, respectively. The detection limits were found to be 0.1 ng for RDX, 10 ng for TNT, 0.5 ng for PETN, 5.0 ng for HMX, and 10 ng for DNT. Simplified chromatograms were observed when nitrogen, as opposed to air, was used as the drift gas, but the detection limits were approximately 10 times worse (i.e., less sensitivity of detection).
Xiaoping Pan - One of the best experts on this subject based on the ideXlab platform.
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rdx induces aberrant expression of micrornas in mouse brain and liver
Environmental Health Perspectives, 2009Co-Authors: Baohong Zhang, Xiaoping PanAbstract:Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX, also known as hexogen or Cyclonite) is a common environmental pollutant resulting from military and civil activities. According to the U.S. Department of Defense, an estimated 12,000 sites across the United States have been contaminated with explosives, including RDX. Concentrations of RDX in soils exceed thousands of milligrams per kilogram (Jenkins et al. 2006). RDX and its metabolites were also identified in water sources, including groundwater (Beller and Tiemeier 2002). Environmental contamination by RDX and its N-nitroso metabolites has raised health concerns about human and environmental exposure (Zhang et al. 2008). It has long been known that RDX exposure causes neurotoxicity, immunotoxicity, and an increased likelihood of cancers. A causal relationship has been established between seizures and acute occupational RDX exposure in humans, with results confirmed in laboratory animals (Burdette et al. 1988; Pan et al. 2007; Testud et al. 1996). One early study demonstrated that RDX exposure elevated the incidence of tumors in B6C3F1 mice (Lish et al. 1984). Based on these findings, RDX has been classified as a class C potential human carcinogen by the U.S. Environmental Protection Agency (U.S. EPA 1988). Despite evidence supporting the role of RDX as a cytotoxic agent and potential chemical carcinogen, the molecular mechanism of RDX-induced neurotoxicity and potential carcinogenesis remains unknown. Recently identified microRNAs (miRNAs) may play an important role in RDX exposure and in the process of RDX-induced tumorigenesis and neurotoxicity. miRNAs are a group of small non-protein-coding endogenous RNAs that posttranscriptionally regulate the expression of > 30% of human protein-coding genes (Lewis et al. 2005). miRNAs negatively regulate gene expression through translation inhibition, mRNA cleavage, or deadenylation/decap-mediated mRNA decay (Giraldez et al. 2006; Wu et al. 2006). These mechanisms are likely governed by the degree of complementarity between mRNAs and their targeting miRNAs (Zhang et al. 2007b). In animals, most miRNAs bind to their target mRNAs imperfectly for repressing protein translation at multiple complementary sites within the 3k untranslated regions (UTRs) (Ambros 2001), with a few exemptions at the open reading frames or 5k UTRs (Lytle et al. 2007). Many miRNAs are evolutionarily conserved in animals, from worms to humans (Pasquinelli et al. 2000), suggesting that miRNA functions are conserved from species to species. miRNAs play an important role in almost all fundamental biological and metabolic processes in eukaryotic organisms (Zhang et al. 2007b). Many recent studies have demonstrated that miRNAs regulate cancer development, including cancer invasiveness and metastasis. Most commonly occurring cancers are associated with the aberrant expression of at least one miRNA (Zhang et al. 2007a). Moreover, it has been established that specific cancers have their unique miRNA expression profiles (Lu et al. 2005), suggesting that miRNAs respond to different cancers in different ways. Thus, miRNA profiles are useful for classifying and identifying cancers. Changes in miRNA expression can regulate the cancer development cascade. A recent in vitro study showed that transient overexpression of the miRNA let-7 in A549 lung adenocarcinoma cell lines inhibited lung cancer cell proliferation (Takamizawa et al. 2004). Another study found that changes in the expression levels of a single miRNA (miR-10b) could initiate tumor invasion and metastasis (Ma et al. 2007). It is well known that many chemical toxicants and biological toxins cause different types of cancers. Although various environmental carcinogens cause DNA and chromosome damage as well as the aberrant expressions of cancer-related genes and toxicant-metabolizing enzymes, the pathogenic mechanisms of toxicant/toxin-induced cancers are unclear (de Kok et al. 2005; Myllynen et al. 2007). Because miRNAs play important roles in cancer development, and the aberrant expression of miRNAs has been observed in different cancers, we hypothesized that the exposure to a specific environmental procarcinogen, such as RDX, would induce alterations in miRNA expression, and that the altered miRNA expression contributes to carcinogenesis. To test this hypothesis, we exposed B6C3F1 mice to RDX and investigated the effect of RDX exposure on the global expression profile of miRNAs, particularly on the oncogenic, tumor-suppressing, and disease-related miRNAs. We assayed RDX-induced changes in miRNAs using microarray and quantitative real-time polymerase chain reaction (qRT-PCR) technologies. Given that miRNAs are highly conserved between mice and humans, the results would help us better understand the molecular mechanisms of RDX-related diseases, including potential carcinogenic and neurologic damages.
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Extraction and analysis of trace amounts of Cyclonite (RDX) and its nitroso-metabolites in animal liver tissue using gas chromatography with electron capture detection (GC-ECD)
Talanta, 2005Co-Authors: Xiaoping Pan, Baohong Zhang, George P CobbAbstract:An efficient extraction and cleanup technique, and an instrumental detection method suitable for determination of trace amounts of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and its nitroso-metabolites in animal liver tissue were developed and validated in this paper. The method includes the extraction of explosives from liver tissue samples using accelerated solvent extraction (ASE) followed by cleanup using florisil and styrene-divinyl benzene (SDB) cartridges to remove interfering naturally endogenous compounds. The instrumental analysis was conducted using a capillary column gas chromatograph coupled with an electron capture detector (GC-ECD). High recoveries (58.9-106.8%) of RDX, 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) were achieved at all concentrations studied. RDX, MNX, and TNX gave higher recoveries than DNX at all three tested concentrations (50, 250, 1250 ng/g). Overall recoveries of RDX, MNX, DNX, and TNX from 1g beef liver samples containing 50, 250, and 1250 ng/g were 80.1, 82.8, 68.9, and 80.4%, respectively. The optimal injection port temperature range was 160-170 degrees C for analysis of RDX and its nitroso-metabolites. Higher or lower temperatures than 160-170 degrees C decreased signal amplitudes. RDX was unstable in the liver extraction matrix; as much as 50% of RDX was degraded 10 days after extraction if keeping the liver sample extracts at room temperature. Degradation of RDX to MNX, DNX, or TNX was not detected during the sample storage, extraction, or instrument analysis processes. Other optimized extraction and GC conditions are also discussed.
George P Cobb - One of the best experts on this subject based on the ideXlab platform.
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extraction and analysis of trace amounts of Cyclonite rdx and its nitroso metabolites in animal liver tissue using gas chromatography with electron capture detection gc ecd
Talanta, 2005Co-Authors: Baohong Zhang, George P CobbAbstract:Abstract An efficient extraction and cleanup technique, and an instrumental detection method suitable for determination of trace amounts of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and its nitroso-metabolites in animal liver tissue were developed and validated in this paper. The method includes the extraction of explosives from liver tissue samples using accelerated solvent extraction (ASE) followed by cleanup using florisil and styrene-divinyl benzene (SDB) cartridges to remove interfering naturally endogenous compounds. The instrumental analysis was conducted using a capillary column gas chromatograph coupled with an electron capture detector (GC–ECD). High recoveries (58.9–106.8%) of RDX, 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) were achieved at all concentrations studied. RDX, MNX, and TNX gave higher recoveries than DNX at all three tested concentrations (50, 250, 1250 ng/g). Overall recoveries of RDX, MNX, DNX, and TNX from 1 g beef liver samples containing 50, 250, and 1250 ng/g were 80.1, 82.8, 68.9, and 80.4%, respectively. The optimal injection port temperature range was 160–170 °C for analysis of RDX and its nitroso-metabolites. Higher or lower temperatures than 160–170 °C decreased signal amplitudes. RDX was unstable in the liver extraction matrix; as much as 50% of RDX was degraded 10 days after extraction if keeping the liver sample extracts at room temperature. Degradation of RDX to MNX, DNX, or TNX was not detected during the sample storage, extraction, or instrument analysis processes. Other optimized extraction and GC conditions are also discussed.
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Extraction and analysis of trace amounts of Cyclonite (RDX) and its nitroso-metabolites in animal liver tissue using gas chromatography with electron capture detection (GC-ECD)
Talanta, 2005Co-Authors: Xiaoping Pan, Baohong Zhang, George P CobbAbstract:An efficient extraction and cleanup technique, and an instrumental detection method suitable for determination of trace amounts of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and its nitroso-metabolites in animal liver tissue were developed and validated in this paper. The method includes the extraction of explosives from liver tissue samples using accelerated solvent extraction (ASE) followed by cleanup using florisil and styrene-divinyl benzene (SDB) cartridges to remove interfering naturally endogenous compounds. The instrumental analysis was conducted using a capillary column gas chromatograph coupled with an electron capture detector (GC-ECD). High recoveries (58.9-106.8%) of RDX, 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) were achieved at all concentrations studied. RDX, MNX, and TNX gave higher recoveries than DNX at all three tested concentrations (50, 250, 1250 ng/g). Overall recoveries of RDX, MNX, DNX, and TNX from 1g beef liver samples containing 50, 250, and 1250 ng/g were 80.1, 82.8, 68.9, and 80.4%, respectively. The optimal injection port temperature range was 160-170 degrees C for analysis of RDX and its nitroso-metabolites. Higher or lower temperatures than 160-170 degrees C decreased signal amplitudes. RDX was unstable in the liver extraction matrix; as much as 50% of RDX was degraded 10 days after extraction if keeping the liver sample extracts at room temperature. Degradation of RDX to MNX, DNX, or TNX was not detected during the sample storage, extraction, or instrument analysis processes. Other optimized extraction and GC conditions are also discussed.
