Lead(II) ion selective electrodes with PVC membranes based on two bis-thioureas as ionophores: 1,3-bis(N'-benzoylthioureido)benzene and 1,3-bis(N'-furoylthioureido)benzene.
Two PVC membrane ion selective electrodes for Pb(II) ion based on two bis-thioureas: 1,3-bis(N'-benzoylthioureido)benzene and 1,3-bis(N'-furoylthioureido)benzene as ionophores, are reported. A first membrane formulated using 1,3-bis(N'-benzoylthioureido)benzene as carrier exhibited a Nernstian response to Pb(II) over a wide concentration range (4.0x10(-6) to 1.0x10(-2)M) with a slope of 31.5+/-1.6 mV/dec. It showed a fast response time (t(90%)=14 s) and could be used for 10 weeks without any divergence in potentials. The membrane formulated using 1,3-bis(N'-furoylthioureido)benzene as carrier exhibited a Nernstian response in the concentration range (5.0x10(-6) to 1.0x10(-2) M), with a slope of 30.0+/-1.3 mV/dec. Its response time was t(90%)=14 s, and it could be used for 14 weeks without any divergence in potentials. The two proposed potentiometric sensors revealed acceptable selectivities for Pb(II) over a wide variety of other metal ions and could be used in a pH range of 2.2-6.0. Both electrodes were assayed in direct potentiometric determination of lead in soils (10-30 mg/kg range) with very good performance (0.99935 correlation coefficient in the comparison against ICP-MS method).
Department of Chemistry, Universitat Autònoma de Barcelona, Bellaterra, Catalonia, Spain.
Deivy
D
Wilson
María de los Angeles
Mde L
Arada
Salvador
S
Alegret
Manel
M
del Valle
D001555:Benzene Derivatives; D017736:Ion-Selective Electrodes / Q000592:standards*; D007476:Ionophores / Q000737:chemistry*; D007854:Lead / Q000032:analysis*; D008567:Membranes, Artificial; D011143:Polyvinyl Chloride; D012989:Soil Pollutants / Q000032:analysis; D013890:Thiourea
D001555:Benzene Derivatives; D007476:Ionophores; D008567:Membranes, Artificial; D012989:Soil Pollutants; D007854:Lead; D011143:Polyvinyl Chloride; D013890:Thiourea