[Spectrophotometric determination of trace amount of lead with trimethoxyphenylfluorone in microemulsion after using sulphydryl dextran gel for preconcentration and separation].

In this paper, the color reaction of lead with trimethoxyphenylfluorone (TM-PF) in microemulsion has been studied. Lead (II) reacts with TM-PF to form a stable 1:2 complex at pH 9.1. Its apparent molar absorptivity is 5.32 x 10(4) L x mol(-1) x cm(-1) at 565 nm. Beer's law is obeyed in the range of 0-1.5 microg x mL(-1). Sulphydryl dextran gel (SDG), in which sulphydryl group has a big share, is a new type of metallic ion adsorbent. It presents the advantage of higher adsorption capacity, better reuse ability and higher mechanical stability. So the coexistent metal ions can be separated effectively and lead can be enriched by SDG, greatly improving the selectivity and sensibility of the system. The method was used to determine trace amount of lead in blood, hair and urine samples with satisfactory results.