Simple detection of trace Pb2+ by enrichment on cerium phosphate membrane filter coupled with color signaling.

A Pb(2+) selective membrane filter was fabricated from the fibrous CeO(H(2)PO(4))(2).2H(2)O (CeP) crystals by blending with cellulose fiber. Enrichment of ppb level of Pb(2+) was achieved simply by filtration of aqueous sample solution through the membrane filter. Pb(2+) was strongly retained on the membrane filter by accommodation into the interlayer gallery of a CeP crystal. Visual detection of the enriched Pb(2+) was achieved by subsequent color signaling as PbS deposit upon treatment of the membrane filter with 3% Na(2)S solution. The analytical procedure and sample treatment conditions were optimized with respect to pH of the sample solution, filtration rate and masking of interfering ions. Detection of 20 ppb of Pb(2+) was not interfered by the presence of 1000-fold of Ca(2+), Mg(2+), and up to 100-fold of Fe(3+)and Cu(2+) by masking with 1 x 10(-3) mol dm(-3) of iminodiacetic acid (IDA). Most anions including phosphate (20 000 times) did not interfere with the determination of Pb(2+). The present simple method was applied to the determination of Pb(2+) in real samples like mine valley water.