Determination of benzo[b]naphtho[2,3-d]thiophene (BNT) in sediments using selective heavy atom induced room-temperature phosphorimetry

Room-temperature phosphorescence characteristics of benzo[b] naphtho[2,3-d] thiophene (BNT) were studied under several experimental conditions. Best phosphorescence was obtained using Tl(I) and Pb(II) as heavy atom enhancers, both in the presence of SDS as surface modifier. Under these two conditions of maximum phosphorescence, working curves with three orders of magnitude were achieved and absolute limits of detection and quantification of respectively 0.6 and 2.0 ng in the presence of Tl(I) and 3.2 and 10.7 ng in the presence of Pb(II). The RTP potential for selective trace-level determination was tested using a sediment sample spiked with BNT and using Pb(II) as the selective heavy atom enhancer. The recovery of BNT was very satisfactory (101.5 +/- 7.4%, n = 6) indicating that the method can be properly applied for the analysis of complex samples. The interference potential from other polycyclic aromatic hidrocarbons (pyrene, chrysene, carbazole, 7,9-dimethylbenz[c] acridine and dibenzothiophene) was evaluated and the method was considered selective in the presence of these substances.