Application of sequential injection analysis to the assay of lead retention characteristics by poly(vinylpyrrolidone):: Trace analysis of lead in waters

This paper presents the use of poly(vinylpyrrolidone) (PVP), which is a low-cost polymer for lead preconcentration in natural-water samples. The weak granular structure of this polymer imposed the use of a stainless-steel filter holder for its conditioning in a thin filtering layer. This unit was inserted into a sequential injection analysis system coupled to a flame atomic absorption spectrophotometer (SIA/FAAS). The developed system allows sampling rates of 16 samples/h with a 60-fold enrichment factor and a detection limit of less than 5 mu g/l for a 13 ml sample volume. The performance of the present system was also assessed by carrying out recovery trials, which provided results of between 96% and 101%. The precision of the methodology developed has never been over 3% regarding RSD and 5% for the deviations to the conventional procedure.