Abstract
1,5-Di-(2-fluorophenyl)-3-mercaptoformazan (F
2H
2Dz) immobilized and plasticized with tri-n-butylphosphate (TBP) polyurethane foam (PUF) were found suitable for the detection of mercury(II) and lead(II) in extremely dilute aqueous solutions. In batch mode of extraction with immobilized F
2H
2Dz-foam as low as 0.05 and 0.15 μg ml
−1 of mercury(II) and lead(II), respectively were detected and the colored chelates were found more stable over 72 h. Lower concentrations of these metal ions (≤1 ppb) were detected by plasticized F
2H
2Dz-TBP foam packed in column extraction mode. Semiquantitative determination of these metals was also possible using a suitable standard color scale. The effect of diverse ions on the detection of 1 μg mercury(II) and lead(II) by the proposed F
2H
2Dz-foam test was critically investigated. The method was satisfactorily applied for the detection of mercury(II) or lead(II) in natural water samples.