Analytical Sciences


Abstract − Analytical Sciences, 15(10), 991 (1999).

Application of Sequential Injection Analysis to the Assay of Lead Retention Characteristics by Poly(vinylpyrrolidone): Trace Analysis of Lead in Waters
Alberto N. ARAUJO * , Rui Cerdeira C. COSTA and JoseL. F. C. LIMA
CEQUP/Serv. Quimica-Fisica, Faculdade de Farmacia (U.P.), Rua Anibal Cunha, 164, 4050 Porto, Portugal
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 mg/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. (Keywords: Preconcentration, poly(vinylpyrrolidone), sequential injection analysis/flame atomic absorption spectrophotometry, lead)