Preconcentration And Determination Of Metal Pollutants In Water By Cloud Point Extraction And GFAAS

Cloud point extraction (CPE), a newly burgeoning separation technology, is now drawing more and more interest with the characteristic of environmental friendliness, easy manipulation and high extraction efficiency.Unfortunately, Cloud point extraction was limited to extract metal ions from environmental water after the formation of metal chelates, which was technically unruly and unfeasible for certain metals. In this work, a new CPE method in absence of chelate formation was developed for the determination of some metals. T1, Pb and Mn were directly extracted into micellar phase under certain pH. the proposed CPE was applied to the determination of T1, Pb and Mn by GFAAS successfully. The detection limit of T1, Pb and Mn was 0.018μg/L, 0.49μg/L, and 0.55μg/L for real samples respectively. The relative standard deviations for 7 replicates were less than 5% and the recoveries were in the range of 98.0%～101%.The mechanism of the CPE in absence of chelate formation was also discussed using Pb as model metal.Experimental results and theorical calculation showed it was possible that metal ions were extracted into surfactant micellar phase in form of hydrated metal oxide. And it was anticipated that all metal ions which could formed hydrated metal oxide under high pH condition could be extracted by the proposed CPE in absence of chelate formation.Finally, a simultaneous preconcentration of Ag and Cr was established by CPE in present of chelate and quantitated by GFAAS,with paticular effort on the extraction conditions and chromium speciation.In conclusion,a new CPE method in absence of chelate was successfully developed for the determination of T1, Pb, Mn in tap water and surface water and with appropriate chemical treatment, speciation of metals proved feasible by CPE.