In situ preconcentration of trace metals in high purity water onto graphite tube by multiple injections followed by graphite furnace atomic absorption spectrometry

Direct determination of trace metals at extremely low levels in high purity water is described. The method incorporates an in situ preconcentration technique in the graphite furnace of the atomic absorption spectrometer. The in situ preconcentration process involves multiple injections and evaporation in apyrocoated graphite tube. The feasibility of the proposed method of multiple injections (up to 9×90 μl) prior to analysis has been investigated. A SLRS-2 certified water sample has been used for quality control, and the results are in good agreement with the certified value and with determination by standard addition method. Typically, up to 0.8 ml of sample could be analyzed. Due to the relatively large sample volume, the detection limits for the elements of interest are in the range of 3-9 ng/l.