Significant signal enhancement of dielectric barrier discharge plasma induced vapor generation by using non-ionic surfactants for determination of mercury and cadmium by atomic fluorescence spectrometry

Non-ionic surfactants (NISs) were used to improve the performance of dielectric barrier discharge plasma induced vapor generation (DBD plasma-CVG). The addition of Triton X-114 leads to 5.4 and 5.1 times improvement in the fluorescence signals of DBD plasma-CVG for cadmium and mercury, respectively. The enhancement mechanism was investigated and it was presumed that the presence of NISs increased the reaction kinetics and improved the transport efficiency of volatile species from solutions. Influencing parameters were evaluated in detail, including the concentrations of NISs and flow rates of carrier gas and samples, as well as interferences. The detection limits were 2.4 ng L-1 for Cd and 4.5 ng L-1 for Hg and the relative standard deviations were 3.4% for Cd (1 mu g L-1, n = 5) and 2.6% for Hg (1 mu g L-1, n = 5), respectively. The accuracy of the proposed method was validated by the analysis of simulated natural water samples, GBW08603, GBW(E)080401 and GBW(E)080402.