Determination of silver in environmental samples by tungsten wire preconcentration method-electrothermal atomic absorption spectrometry

A preconcentration method for silver in environmental waters involving adsorption on a tungsten wire, followed by electrothermal atomic absorption spectrometry with a tungsten tube atomizer is described. The optimal immersing time was 90 s. The best pH for the adsorption of silver was 3. Under the optimal conditions, the detection limit for silver by the tungsten wire preconcentration method was 5.0 ng l⁻¹ (3S/N) and the relative standard deviation was 8.2%. The effects of large amounts of concomitants on the preconcentration of silver were evaluated. Even though 10³- to 10⁴-fold excess of matrix elements existed in water, the silver response was not significantly affected by the matrix elements. The method with preconcentration on a tungsten wire was applied to the determination of silver in waters and proved to be sensitive, simple, and convenient. This adsorption method can be utilized in in situ sampling of ultra-trace silver in environmental samples (waters). Furthermore, after sampling it is easy to carry and store the tungsten wire without contamination for a long time.