Determination of mercury species by capillary column GC-QTAAS with purge and trap preconcentration technique

A GC-QTAAS procedure was developed for the determination of methylmercury a nd inorganic mercury(II) in biological samples. A capillary column DB-1 (J& W Scientific) was used for the separation of ethylated mercury species. Sod ium tetraethylborate was used as derivatization reagent. When direct sample introduction did not provide low enough detection limits, a purge and trap preconcentration technique was developed, where the evolved mercury specie s were concentrated on Tenax-ta adsorbent. With this system the measuring r ange was between 0-5 ng (as Hg) for the different species (dimethylmercury, methylmercury and inorganic mercury(II)) in a 100 mul sample. The detectio n limits obtained for a 250 mg sample with the standard addition method wer e 72 mug/kg, 136 mug/kg and 224 mug/kg for dimethylmercury, monomethylmercu ry and inorganic mercury(II), respectively. The method was successfully app lied to the determination of mercury species in the dogfish certified stand ard reference material (DOLT-2).