Analysis of degradation products of nerve agents via post-pentafluorobenzylation liquid chromatography-tandem mass spectrometry.

In the work reported here, a screening procedure was developed for the detection and identification of RMPAs (nerve agent degradation products) after pentafluorobenzylation using liquid chromatography-tandem mass spectrometry (LC-MS/MS). With this method, all RMPAs, including highly hydrophilic types such as methylphosphonic acid (MPA) and ethyl methylphosphonic acid (EMPA), were sufficiently retained in commonly used reversed-phase columns (retention times: 15.7 and 11.0 min.), and the presence of RMPAs was determined more efficiently than with the conventional direct LC-MS/MS method. The detection limits of RMPAs using this approach (<33 ng) were mostly superior to those observed with direct LC-MS/MS (<74 ng) and gas chromatography-mass spectrometry (GC-MS) after pentafluorobenzylation (<1.1 µg). The applicability of newly developed method toward real samples was evaluated via recovery tests involving urine/serum and wipe tests on various surfaces.

Sensitive monitoring of volatile chemical warfare agents in air by atmospheric pressure chemical ionization mass spectrometry with counter-flow introduction.

A new method for sensitively and selectively detecting chemical warfare agents (CWAs) in air was developed using counter-flow introduction atmospheric pressure chemical ionization mass spectrometry (MS). Four volatile and highly toxic CWAs were examined, including the nerve gases sarin and tabun, and the blister agents mustard gas (HD) and Lewisite 1 (L1). Soft ionization was performed using corona discharge to form reactant ions, and the ions were sent in the direction opposite to the airflow by an electric field to eliminate the interfering neutral molecules such as ozone and nitrogen oxide. This resulted in efficient ionization of the target CWAs, especially in the negative ionization mode. Quadrupole MS (QMS) and ion trap tandem MS (ITMS) instruments were developed and investigated, which were movable on the building floor. For sarin, tabun, and HD, the protonated molecular ions and their fragment ions were observed in the positive ion mode. For L1, the chloride adduct ions of L1 hydrolysis products were observed in negative ion mode. The limit of detection (LOD) values in real-time or for a 1 s measurement monitoring the characteristic ions were between 1 and 8 µg/m(3) in QMS instrument. Collision-induced fragmentation patterns for the CWAs were observed in an ITMS instrument, and optimized combinations of the parent and daughter ion pairs were selected to achieve real-time detection with LOD values of around 1 µg/m(3). This is a first demonstration of sensitive and specific real-time detection of both positively and negatively ionizable CWAs by MS instruments used for field monitoring.

Confirmation of the anomeric structure of galacturonic acid in the galacturonosyl-ceramide of Sphingomonas yanoikuyae.

The anomeric structure of glycosphingolipids significantly influences their activity to stimulate natural killer T cells. In this study the chemical structure of the galacturonosyl-ceramide in Sphingomonas yanoikuyae, designated GSL-1'sy, was re-examined to prove the anomeric structure of the Dgalacturonic acid (GalA) in the lipid, which was reported as beta-configuration by Naka et al., but was suggested as alpha-configuration in our preliminary study. GSL-1'sy was purified from the bacterial cells with the same procedure as Naka et al. The 1H-NMR analysis of GSL-1'sy revealed that the coupling constant of the anomeric proton of GalA was 3.0 Hz, indicating that GalA in GSL-1'sy is alpha-anomer, the configuration active for the stimulation of natural killer T cells.

Pralidoxime iodide (2-pAM) penetrates across the blood-brain barrier.

The in vivo rat brain microdialysis technique with HPLC/UV was used to determine the blood-brain barrier (BBB) penetration of pralidoxime iodide (2-PAM), which is a component of the current nerve agent antidote therapy. After intravenous dosage of 2-PAM (10, 50, 100 mg/kg), 2-PAM appeared dose-dependently in the dialysate; the striatal extracellular/blood concentration ratio at 1 h after 50 mg/kg dosage was 0.093 +/- 0.053 (mean +/- SEM). This finding offered conclusive evidence of the BBB penetration of 2-PAM. We also examined whether the BBB penetration of 2-PAM was mediated by a certain specific transporter, such as a neutral or basic amino acid transport system. Although it was unclear, the neural uptake of 2-PAM was Na+ dependent. The mean BBB penetration by 2-PAM was approximately 10%, indicating the intravenous administration of 2-PAM might be to a degree effective to reactivation of the blocked cholinesterase in the brain.

Occurrence of an alpha-galacturonosyl-ceramide in the dioxin-degrading bacterium Sphingomonas wittichii.

The chemical structure of two glycosphingolipids (GSLs) found in the dioxin-degrading bacterium Sphingomonas wittichii strain RW1 was investigated by means of mass spectrometry and (1)H-nuclear magnetic resonance spectroscopy. One of the GSLs was alpha-D-glucuronosyl-ceramide, commonly present in Sphingomonas spp., and the other was proved to be alpha-D-galacturonosyl-ceramide, whose sugar configuration has not been reported before. In both GSLs the ceramide portion was composed of myristic acid or 2-hydroxy-myristic acid as the fatty acid, and 2-amino-1,3-octadecanediol or 2-amino-cis-13,14-methylene-1,3-eicosanediol as the dihydrosphingosine.