Four different fatty acids (C7, C10, C14, and C18) were studied to characte
rize their abilities as lead(II) ion carrier in PVC membrane electrodes. Th
e electrode based on capric acid [CH3(CH2)(8)COOH] shows good Nernestian re
sponse for Pb2+ ions. The optimum composition of the membrane was 30 wt.% p
oly(vinyl chloride), 60 wt.% NPOE as plasticizer, 5 wt.% ionophore, and 5 w
t.% potassium tetrakis (p-chlorophenyl) berate as lipophilic salt. The elec
trode exhibits a Nernstian slope of 29.0 +/- 0.5 mV per decade for Pb2+ ove
r a wide concentration range (1.0 x 10(-5)-1.0 x 10(-2)). It can be used fo
r a period of 3 months without any considerable divergence in potentials. T
he proposed electrode revealed good selectivities for Pb2+ over a wide vari
ety of other metal ions and could be used in the pH range of 4.5-7. It show
s a good stability, good reproducibility, and fast response. The electrode
was used for the potentiometric titration of chromate ions with lead ions.
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