Screening Sediment for Pyrethroid Insecticides Using GC-MS/MS

A simple screening method for pyrethroid insecticides in sediment samples is described. Electron impact ionisation (EI) with tandem MS/MS in combination with programmed
temperature vaporisation injection (PTV) were used to obtain excellent selectivity and low limits of detection (LOD). Pyrethroids are synthetic chemical insecticides whose chemical
structures were adapted from the chemical structures of the pyrethrins. Pyrethroids have been modified to increase their stability in sunlight. They are toxic to aquatic organisms at
extremely low concentrations, especially to invertebrates that are at the bottom of the food chain.
The increased use of pyrethroids in urban areas for mosquito control has led to unintended contamination of local streams and reservoirs due to urban runoff. As a result, state and
federal agencies have initiated monitoring programs to characterise the extent of contamination in water supplies and their potential impact on aquatic life. In general, there are no
set requirements for minimum detection or reporting levels. However, the lowest reporting level that can be achieved by a given technique is desired.
The SCION TQ triple quadrupole mass spectrometer in EI mode with PTV injection is ideal for screening sediment extracts at low to sub-parts-per-billion concentrations. PTV injection
combined with the sensitivity and selectivity of MS/MS result in excellent low-level screening of pyrethroids in river and lake sediments. The SCION TQ with Compound-Based
Scanning (CBS) allows easy set-up and management of the pyrethroid MRM parameters. Compound MRM information is loaded directly into the method by choosing them from the
on-board or user created library. It links the mass spectrometer acquisition table directly with data handling parameters, streamlining the data process.