a novel, simple, sensitive and effective method has been developed for preconcentration of hg(ii) on nano-fe3o4-dop-ed solid-phase extraction adsorbent. in this paper, dioctyl phthalate (dop) was used to encapsulate nano-fe3o4 and produce a nano-fe3o4-dop sorbent based new sorbent was prepared. this was treated with ethylenediamine (ed) in another solvent-free procedure for the formation of a n...