Evaluation of polychlorotrifluoroethylene as sorbent material for on-line solid phase extraction systems: determination of copper and lead by flame atomic absorption spectrometry in water samples.

Polychlorotrifluoroethylene (PCTFE) in the form of beads was applied, as packing material for flow injection on-line column preconcentration and separation systems coupled with flame atomic absorption spectrometry (FAAS). Its performance characteristics were evaluated for trace copper determination in environmental samples. The on-line formed complex of metal with diethyldithiophosphate (DDPA) was sorbed on the PCTFE surface. Isobutyl methyl ketone (IBMK) at a flow rate of 2.8 mL min(-1) was used to elute the analyte complex directly into the nebulizer-burner system of spectrophotometer. The proposed sorbent material reveal, excellent chemical and mechanical resistance, fast adsorption kinetics permitting the use of high sample flow rates up to 15 mL min(-1) without loss of retention efficiency. For copper determination, with 90 s preconcentration time the sample frequency was 30 h(-1), the enhancement factor was 250, which could be further improved by increasing the loading (preconcentration) time. The detection limit (3s) was c(L)=0.07 microg L(-1), and the precision (R.S.D.) was 1.8%, at the 2.0 microg L(-1) Cu(II) level. For lead determination, the detection limit was c(L)=2.7 microg L(-1), and the precision (R.S.D.) 2.2%, at the 40.0 microg L(-1) Pb(II) level. The accuracy of the developed method was evaluated by analyzing certified reference materials and by recovery measurements on spiked natural water samples.