Comparison of Solid-Phase Extraction and Solid-Phase Microextraction Using Octadecylsilane Phase for the Determination of Pesticides in Water Samples

Sample treatment/preparation procedures using octadecylsilane as common phase for solid-phase extraction (SPE) and solid-phase microextraction (SPME) were compared for the analysis of the pesticides pyrimethanil, kresoximmethyl and tebufenpyrad in water samples. SPE and SPME were followed by gas chromatography-mass spectrometry (GC-MS). SPE require 500 mL of sample and leads to a limit of detection in the range 0.005-0.02 ng/mL. SPME requires only 4.0 mL of sample and provides a limit of detection in the range 0.004-0.03 ng/mL. No significant difference between pesticides found in spiked samples using SPE and SPME were obtained. The main advantages of SPE were better precision and ruggedness. The main advantage of SPME method is that the cost of octadecylsilane fiber is negligible compared to octadecylsilane 500 mg cartridges or SPME commercial fibers.