Hemlata Rana

In vitro reactivation of organophosphorus (OP)-inhibited electric eel acetylcholinesterase by novel monoquaternary pyridinium oximes

The synthesis of a series of monoquaternary pyridinium oximes bearing either a long-chain alkyloxymethyl or benzyloxymethyl side chain and the corresponding in vitro evaluation for the reactivation of electric eel acetylcholinesterase-inhibited organophosphorus inhibitors viz. sarin, DFP, and VX is reported. The data were compared with that of 2-PAM and obidoxime. Compounds bearing a benzyloxymethyl and 4-methylbenzyloxymethyl side chain showed better reactivation compared to obidoxime. However, none of the newly synthesized oximes bearing an aliphatic side chain could surpass the reactivation potential of 2-PAM. The pKa of the new oximes were determined and correlated with the observed reactivation potential.

Selective and sensitive chromogenic and fluorogenic detection of sulfur mustard in organic, aqueous and gaseous medium

We present a highly selective and sensitive detection protocol for the chemical warfare agent sulfur mustard (SM). The chromogenic and fluorogenic system uses a squaraine dye (SQ) that not only detects SM but also discriminates it from other chemical warfare agents (CWAs) and potent electrophilic interferents. A water soluble dithiol, 2-(3,5-bis(mercaptomethyl)phenoxy)acetic acid 1, in the presence and absence of SM, behaves differently towards the squaraine dye (SQ) to give different chromogenic and fluorogenic responses. With an aim to mimic real-life scenarios for the onsite and offsite detection, the sensing protocol was further implemented in spiked water and soil samples, on surfaces, and in the gas phase. The lower detection limit (much lower than the lethal dose) of both visual inspection and the fluorescence technique will be highly useful to mankind in order to sensitively detect SM.

Chromogenic and fluorogenic multianalyte detection with a tuned receptor: refining selectivity for toxic anions and nerve agents

In the present study, a chemical probe was finely tuned for the highly selective and sensitive chromogenic and fluorogenic detection of toxic anions and a nerve agent. Studies on the binding sites, signaling units and spacers led to a receptor molecule, i.e., 2,7-bis-[3-(4-cyanophenyl)thiourea] fluorene 2, which detected multiple analytes such as fluoride, cyanide, and a tabun mimic. The optical responses obtained from all the three analytes were quite distinct from one another. More importantly, we have been successful in demonstrating the highly specific chromo-fluorogenic detection of a tabun mimic over other chemical warfare agents and reactive and non-reactive electrophilic interferents. In an attempt to mimic real-life scenarios, the applicability of our protocol was further extended to demonstrate the presence of a tabun mimic on solid surfaces, in the gas phase and in a spiked soil sample.

Rapid Analysis of Dithiaalkane Diols by HPLC

Abstract A reversed‐phase high performance liquid chromatography (HPLC) method has been developed for simultaneous detection of dithiaalkanediols, having the common formula [(HO–CH2–CH2–S)2(CH2) n ] in a homologues series where n = 1–10. Both isocratic and gradient methods were developed, and the latter was found to be suitable for both qualitative and quantitative analysis. The method is simple, specific, and requires only small quantities of chemicals and reagents.