1Central Forensic Science Laboratory, Ramanthapur, Hyderabad, Andhra Pradesh, 500013
2Director, Institute of Science and Technology, JNTU, Hyderabad, Andhra Pradesh
Pesticides help to augment agricultural productivity by reducing crop loss. Organophosphate pesticides are commonly used to control many biting or sucking insect pests of agricultural crops, primarily cotton, vegetables, and food grains. Because of easy availability, they are widely used by farmers in South India to commit suicide. They are soluble in most organic solvents like n-Hexane, dichloromethane, 2-propanol, and toluene. They act by inhibiting the enzyme acetylcholinesterase resulting in the stimulation of central nervous system, parasympathetic nervous system, and the motor nerves.
The new method of isolation from a different matrix was compared with the existing method by separation, cleanup, and identification using modified GCMS. Different organic solvents (hexane, dichloromethane, and toluene) were tried for the isolation and extraction of organophosphorous compounds such as methyl parathion, chlorpyriphos, and malathion from biological matrices. TLC with different solvents were tried and visualized with chromogenic reagents for semi qualitative analysis. The samples were qualitatively analyzed and the identity of the sample was confirmed by the mass fragmentation pattern of the samples compared with the standard Mass Spectrum (NIST) from the library. The multiresidue method of organophosphorous detection was modified, and the samples were analysed using GC-MS. The standards and the recovery studies of the samples were carried out for dichlorvos, phosheptanex, phosdrin, phorate, disystox, phosmadion, methyl parathion, malathion, chlorpyriphos, and quinalphos.
The retention times for the above pesticides were standardized and the sample extracts from biological matrices were compared and spectrum identified.
