Separation and determination of mercury from nail and hair in petrochemical workers based on silver carbon nanotubes by microwave-assisted headspace sorbent trap

In this work, the occupational analytical chemistry was developed for determination of chronic exposure of mercury in nail and hair in petrochemical workers (Age: 30-50, Men). By experimental procedure, 100 mg of hair and nail of workers was prepared by washing / grinding and then the powder was dried in 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. After microwave digestion for 25 min, the mercury vapor was removed by Ag-MWCNTs as the headspace sorbent trap (HSST) under hood conditions. Finally, the mercury in sorbent was online determined by cold vapor atomic absorption spectrometry (CV-AAS) after heat process at 250oC in presence of Ar gas. The capacity adsorptions of Ag-MWCNTs and MWCNTs for mercury removal from air were obtained 205.4 mg g-1 and 63.7 mg g-1, respectively. The mean of mercury in nail and hair in workers and healthy peoples was achieved (15.2±3.7 μg g-1; 11.6± 2.6 μg g-1) and (0.16±0.05 μg g-1; 0.24± 0.03 μg g-1), respectively (RSD<5%). The validation of method was done by certified reference material (CRM).