Flow injection solid phase extraction with Chromosorb 102: determination of lead in soil and waters by flame atomic absorption spectrometry

A flow-injection, solid-phase extraction, preconcentration method was developed for the determination of lead in soil and water samples by flame atomic absorption spectrometry. Lead, in the form of the diethyldithiocarbamate complex, was retained on a miniature column of Chromosorb 102 from buffered sample solutions. Several parameters governing the efficiency and throughput of the method were evaluated including pH, eluent composition, volume and flow rate. The complex retained from pH 9.0 (ammonium acetate) solutions was eluted with 176 μl of ethanol, at 4.2 ml min−1 into the nebulizer–burner system of the spectrometer. The detection limit was 2 μg l−1 for preconcentration at 2.2 ml min−1 for 120 s. The relative standard deviation (R.S.D.) was less than 4% for concentrations down to 400 μg l−1. The procedure was validated by the analysis of NIST standard reference material 2711 (Montana Soil) which contains lead at a concentration of 1162 μg g−1. Recoveries of spike additions (100–400 μg l−1) to artificial sea water and tap water were quantitative.