Comprehensive investigation and optimisation of the main experimental variables in stir-bar sorptive extraction (SBSE)-thermal desorption-capillary gas chromatography (TD-CGC)

A chemometric study has been completed in order to investigate the relative contributions and interactions between the many experimental variables involved in SBSE-TD-CGC. The study was centered on data after extraction and analysis of important organophosphorous pesticides from water under different controlled conditions. An enhanced flame photometric detector was used for target compound area response. The seemingly independent operations of extraction with the stir bar followed by thermal transfer of the absorbed compounds to the chromatographic system are usually studied by independent designs for the corresponding blocks of variables. In this work all variables are treated at the same time in a single design to study the interactions and give a more robust model while requiring a lower number of experiments. The relative importance of contributing variables was clearly established and an optimum set of conditions was established for more uniform enrichment in a single analysis for a test mix of compounds with wide ranging polarities.