Determination of Pyrethroid Residues in Tobacco by Means of Solid Phase Microextraction and GC/MS with the Aid of Ultrasonic Assisted Extraction Using Water as Extracting Solvent

A rapid and simple sampling approach using solid phase microextraction (SPME) for pyrethroid residues analysis in flue- cured tobacco was studied. The fibers coated with poly-dimethylsiloxane (PDMS) at 100 gm thickness were chosen. Extraction time of 180 s, desorption time of 120 s and desorption temperature of 280°C were selected. The whole sampling process, only including an ultrasonic assisted extraction step and a solid phase microextraction step, can be completed within 15 min. The associated SPME and ultrasonic assisted extraction using water as extracting solvent shows good results for tobacco pyrethroid residues determination. Results indicated that four pyrethroids can be determined simultaneously, and the limits of detection are below 35 ng g-1 using GC/MS in selected ion monitoring (SIM) mode. The reproducibility of the technique is found to be better than 11.8% RSD.