Automated and semi-automated extraction methods for GC-MS determination of pesticides in environmental samples

A highly efficient extraction of analytes is crucial for the determination of pesticides in environmental samples at ultra-trace levels. In order to reduce sample handling and improve analysis productivity, extraction methods should be automated. However, fully automation is not always possible. In the present review, the use of automated and semi-automated extraction procedures coupled to gas chromatography mass spectrometry (GG-MS) for the determination of pesticides in environmental samples are revised, highlighting their advantages as well as their disadvantages. Among automated or semi-automated extraction techniques, solid phase microextraction (SPME) is the most widely used methodology for the determination of pesticides in environmental samples. In addition, analytical methods based on automated solid phase extraction (SPE) or extraction procedures requiring minimal sample handling, such as stir bar sorptive extraction (SBSE) and liquid phase microextraction (LPME) procedures, have also been coupled to GC-MS and applied for the determination of pesticides in environmental samples. Therefore, methodologies based on these extraction techniques are also considered in this paper. The combination of these procedures with GC-MS has allowed the determination of pesticides with acceptable relative recoveries (>70% in most cases) and low limits of detection (LOD), in the range of few μg L−1-ng L−1. Nevertheless, increased efforts aimed at achieving the highest possible recoveries and lowest LOD values, as well as the complete automation of the analytical techniques, are still required.