Solventless sample preparation procedure for organophosphorus pesticides analysis using solid phase microextraction and on-line supercritical fluid extraction/high performance liquid chromatography technique

Organophosphorus pesticides spiked in water sample solutions were extracted with solid phase microextraction (SPME) technique and were desorbed by supercritical fluid carbon dioxide (SFCO2) before on-line introduction into high performance liquid chromatography system (HPLC). All of the 5-µl SFCO2 injected into the HPLC system were dissolved into the methanol/water (80/20) mobile phase without affecting the baseline of the UV detector signal. Preliminary experiments were performed in order to optimize the extraction conditions of pesticides from spiked water solutions with the SPME technique. Subsequently, desorption conditions of the pesticides from the SPME fiber coating using SFCO2 as the desorption medium were optimized.