ABSTRACT
Use of mosquito repellents is a popular way of avoiding mosquito bites. These repellents are quite effective, but can be toxic when misused. These substances are periodically involved in accidental, homicidal and suicidal poisoning cases. The study being presented deals with thin layer chromatographic (TLC) analysis of six samples of different brands of liquid mosquito repellents available in the local markets of India. The results reveal a discernible separation of the components of the selected samples. This could help forensic toxicologists in the quick and economical analysis of samples of mosquito repellents.
ABSTRACT
Rats are among the most destructive of pests, ravaging crops and prepared food material. A variety of rodenticides are available in India for killing these pests, and among them, the most common compounds include zinc phosphide and bromadiolone. While there is little doubt that they are effective rodenticides, the flip side is that they are increasingly being employed for committing suicide, and even homicide. Thin layer chromatography, an inexpensive and relatively simple method for detecting various poisons has rarely been employed in detecting bromadiolone in biological materials. An attempt has therefore been made in this study to identify bromadiolone in biological samples. This can be employed in clinical and forensic cases as a preliminary test, which if necessary can subsequently be confirmed with more sophisticated analyses.
ABSTRACT
A thermostable lipase was partially purified from the culture supernatant of a thermophilic Bacillus sp. The enzyme is optimally active at 60ºC and pH 8.0. The enzyme showed enhancement in activity in presence of benzene or hexane (30 percent v/v each). The activity (assayed by determining the release of pNP from pNP laurate) was stimulated up to 60 percent of these solvents in enzyme reaction mixture. The catalytic properties of this thermostable enzyme can be further improved via the use of different immobilization techniques and reaction conditions. Enzyme was immobilized on different solid supports and their enzyme activity and stability was compared. The enzyme was adsorbed on silica and HP-20 beads followed by cross-linking with gluteraldehyde on HP-20, which improved the thermostability of enzyme. The optimum pH (pH 8.5) was nearly same for aqueous and immobilized enzyme while optimum temperature was nearly 5ºC higher in case of immobilized enzyme. The immobilized/cross linked enzyme was more thermostable at 70 and 80ºC in comparison to aqueous and surface adsorbed lipase on silica and HP-20. The optimum temperature for esterification reactions was determined to be 60-65ºC. Half-life of immobilized lipase was nearly 2.5 x higher than the aqueous enzyme at 70ºC. Esterification of methanol and oleic acid to methyl oleate by immobilized enzyme was studied in detail.
ABSTRACT
Forensic scientists are often confronted with cases where seeds of poisonous plants are used in the commission of crime. Identification of these poisonous seeds is always a tough job because literature does not provide any significant reference work regarding this important aspect. In the present work, five seed samples of four different poisonous plant species were selected and Thin Layer Chromatography (TLC) was employed for the separation of their constituents. While advanced instrumental techniques are available, TLC is an economical and simple method that can be used in any laboratory. Various solvent systems were tried for analysis, and led to the discovery of an effective solvent system. This study is hoped to help forensic toxicologists in answering some queries related to TLC analysis of plant poisons.