Central Forensic Science Laboratory, Ramanthapur, Hyderabad-500013
Hypnotic/sedative use in drug related offences is on the rise, as evidenced from the trend of cases encountered in forensic laboratories. The benzodiazepine group of drugs is most commonly encountered in such forensic cases. The onset of action of these drugs is immediate, and is therefore favoured by the culprits to commit crimes such as theft, robbery of passengers in public transport, and sexual offences. Of these drugs, lorazepam and diazepam possess properties that can lead to their rapid deterioration. Successful detection depends on the dose and time of administration, as well on age, sex, and other aspects of the person concerned. The chance of detection in such a situation increases with the type of instrument and technique adopted to identify the drug from the complex matrix. The detection of lorazepam by TLC, HPLC, and GC is reported in this study.
A dead body was found with a syringe nearby. The doctor who was called to the scene reported the person dead, and preserved relevant viscera for chemical analysis. The autopsy could not confirm the injection of any drug. After routine chemical analysis, the presence of a basic drug was deduced. Modified TLC system was done - Chloroform: Methanol: ammonia:: 90:10:1, Sprayed with Dragon-droff reagent and confirmed by FTIR, KBR spectra and library match. GC-MS was done with Column 5% phenyl methyl silicone, injector port 200, interface 200 degree, EI mode, 70 eV, Mass range 40- 630 amu. Oven temperature 70°C for 1min, @ 5°C to 200°C hold 1min, @ 10°C up to 250°C, carrier gas helium 1ml/min, ionization voltage: 70 eV, EI mode.
The analytical methodology followed could conclusively identify the presence of lorazepam in the biological samples, and the recovered syringe at the scene of crime.
