Contamination of ground water by arsenic has become a cause of global public health concern. In West Bengal, India, almost 6 million people are endemically exposed to inorganic arsenic by drinking heavily contaminated groundwater through hand-pumped tube wells. No safe, effective and specific preventive or therapeutic measures for treating arsenic poisoning are available. We recently reported that some of the herbal extracts possess properties effective in reducing arsenic concentration and in restoring some of the toxic effects of arsenic in animal models. Moringa oleifera Lamarack (English: Horseradish-tree, Drumstick-tree, Hindi: Saijan, Sanskrit: Shigru) belongs to the Moringaceae family, is generally known in the developing world as a vegetable, a medicinal plant and a source of vegetable oil. The objective of the present study was to determine whether Moringa oleifera (M. oleifera) seed powder could restore arsenic induced oxidative stress and reduce body arsenic burden. Exposure to arsenic (2.5 mg/kg, intraperitoneally for 6weeks) led to a significant increase in the levels of tissue reactive oxygen species (ROS), metallothionein (MT) and thiobarbituric acid reactive substance (TBARS) which were accompanied by a decrease in the activities in the antioxidant enzymes such as superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) in mice. Arsenic exposed mice also exhibited liver injury as reflected by reduced acid phosphatase (ACP), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) activities and altered heme synthesis pathway as shown by inhibited blood delta-aminolevulinic acid dehydratase (delta-ALAD) activity. Co-administration of M. oleifera seed powder (250 and 500 mg/kg, orally) with arsenic significantly increased the activities of SOD, catalase, GPx with elevation in reduced GSH level in tissues (liver, kidney and brain). These changes were accompanied by approximately 57%, 64% and 17% decrease in blood ROS, liver metallothionein (MT) and lipid peroxidation respectively in animal co-administered with M. oleifera and arsenic. Another interesting observation has been the reduced uptake of arsenic in soft tissues (55% in blood, 65% in liver, 54% in kidneys and 34% in brain) following administration of M. oleifera seed powder (particularly at the dose of 500 mg/kg). It can thus be concluded from the present study that concomitant administration of M. oleifera seed powder with arsenic could significantly protect animals from oxidative stress and in reducing tissue arsenic concentration. Administration of M. oleifera seed powder thus could also be beneficial during chelation therapy with a thiol chelator.

Retrospective detection and identification of chemical warfare agents (CWAs) is important from the verification point of view of the Chemical Weapons Convention. In the present work, a novel method for determination of CWAs and their markers in water has been described. It is based on a single drop micro extraction (SDME) of analytes and gas chromatography/mass spectrometric identification. Extraction conditions, such as solvent selection, agitation, extraction time, and salt content, were found to have significant influence on SDME. The conditions optimized for extraction of CWAs were 1 microL CH2Cl2/CCl4 (3:1 v/v), 30-min extraction time, 300-rpm stirring rate, and with or without NaCl addition. Under optimized conditions, comparison of SDME, solid-phase microextraction, and liquid-liquid extraction was also made. The limit of detection by SDME ranged from 75 to 10 microg L(-1) at a signal-to-noise ratio of 10:1.

No abstract

No abstract

The kinetics of nucleophilic dephosphorylation of p-nitrophenyl diphenyl phosphate by hydroxamate ions (R'(C=O)N(RO-)) have been investigated in aqueous cationic micellar media at pH 9.12 and 27 degrees C. The pseudo-first-order rate constant-surfactant profiles show micelle-assisted bimolecular reactions involving interfacial ion exchange between bulk aqueous media and micellar pseudophase. N-Substituted hydroxamate ion shows higher reactivity over the unsubstituted hydroxamate ions in cationic micellar media. The kinetic data are discussed in terms of the pseudophase ion exchange model.

This communication describes the synthesis and gas chromatography/mass spectrometric (GC/MS) analysis of N,N-dialkylphosphoramidic dihalides and alkylphosphonic difluorides, which are synthones of nerve agents. The study was undertaken with a view to developing a spectral database of these compounds for verification purposes of the Chemical Weapons Convention (CWC). The modified synthetic approach reported here has advantages over traditional syntheses in terms of time and yield. GC/MS analysis of these synthones yielded electron ionization (EI) mass spectra and, based on these spectra, generalized fragmentation routes are proposed that rationalize most of the characteristic ions.

No abstract

Off-site analysis of chemical warfare agents (CWAs) and related compounds plays a key role in the verification program of the Chemical Weapons Convention (CWC). The analysis results, aiming toward unambiguous identication of compounds, depend on the type of sample preparation method. Development of milder sample preparation methods, which offer good recoveries and do not alter the structure of analytes, is highly desirable. Organic liquid with high hydrocarbon background is a frequently encountered challenge in off-site analysis and in official proficiency tests conducted by OPCW. Sample cleanup procedures, namely, solvent exchange followed by cooling and liquid-liquid extraction were studied to eliminate the hydrocarbons from organic liquid. Acetonitrile, a polar aprotic solvent, was effectively used to remove the background in both methods, and recoveries of spiked CWAs by the two techniques were between 69 and 99%.