Different parameters influence the extraction efficiency in an SPME experiment; thus, optimization of the parameters is an important step in each analysis. Optimization of affecting extrac- tion parameters, including temperature, salt (NaCl) percent, sonication time, adsorption time and sample volume, was performed using a simplex optimization method [18]. The simplex method can significantly decrease the number of required experi- ments for the achievement of a target maximum. In this case, six (n + 1) initial experiments were designed. The conditions corre- sponding to the worst response was then reflected and the