Sample introduction assisted by compressed air in flame furnace AAS: a simple and sensitive method for the determination of traces of toxic elements

摘要

The power of detection of flame AAS for the toxic elements Cd, Hg, Pb and TI can be improved by 1-2 orders of magnitude by using flame furnace AAS. In flame-furnace AAS, liquid samples are introduced directly into a nickel tube located in the flame, in the simplest case through a ceramic thermospray capillary. Transportation of the samples is achieved by using compressed air only. Comparatively low detection limits are achieved by both beam injection flame furnace (BIFF-AAS) and thermospray flame furnace AAS (TS-FF-AAS). For TS-FF-AAS, a pressure of less than 20 kPa ( < 80 in. water) is required. The TS-FF-AAS technique is very simple, robust and cheap. The detection limits were 0.2-0.4 mu g L-1 (Cd), 40-100 mu g L-1 (Hg), 5-9 mu g L-1 (Pb) and 4-14 mu g L-1 (TI), respectively, depending on the method, flow rate and sample volume used. Pb and Cd were found at concentrations of 0.1-2 and 0.005-0.3 mu g g(-1) respectively, in samples of various spices.