Immunoassay for the detection of lead ions in environmental water samples.

A rapid, simple, and reliable competitive immunoassay was developed for
measurement of lead ions Pb(II) in environmental samples. Avian antibodies were
produced against Pb(II). Since lead ions are too small to elicit an immune
response, the metal was coupled to protein carrier Bovine serum albumin (BSA)
using a bifunctional chelator 1-(4-isothiocyanobenzyl) ethylenediamine N,N,N0,
N0-tetra acetic acid (ITCBE). Poultry birds (layers) were immunised with this
Pb(II)–ITCBE–BSA immunoconjugate and the avian antibodies (IgY) isolated
from egg yolk recognised Pb(II)-ITCBE complexes as capture reagent and a
Pb(II)–ITCBE conjugate of Alkaline phosphatase as an enzyme label. Antibody
reaction was optimised for different concentrations of antigen and antibody
dilutions. Cross reactivity with other metals were below 1% in competitive ELISA.
The IC50 value of this avian antibody was 0.19 mgmL�1. The detection range and
the detection limit were 0.02–1000 mgmL�1and 0.2 mgmL�1, respectively.