In this work, a robust method was developed for the determination of mercury in nail and hair in petrochemical workers. By experimental procedure, 100 mg of hair and nail of workers was prepared as a powder which dried in the oven for 20 min at 95oC.  20 mg of hair or nail samples added to reagents (HNO3/H2O2; 5:1) in polyethylene tube (PET) of microwave digestion and the mercury in resulting solution was removed with silver nanoparticles pasted on multi-walled carbon nanotubes (Ag-MWCNTs) which were placed in head space of separator. The mercury vapor was removed by Ag-MWCNTs as the headspace sorbent trap (HSST) under hood conditions. Finally, the mercury was online determined by cold vapor atomic absorption spectrometry after the heat process at 250oC in the presence of Ar gas. The capacity adsorptions of Ag-MWCNTs and MWCNTs for mercury removal were obtained 205.4 mg g-1 and 63.7 mg g-1, respectively.