TITLE:
Polyvinylbenzyl Tris-Aminodicarboxylate Microspheres for the Optical Sensing of Cu2+ Ions
AUTHORS:
Ziad M. Shakhsher, Ibrahim Abu Shqair, Hanin R. Qasim, Imad Odeh
KEYWORDS:
Tris(2-aminoethyl)aminodicarboxylate-Polymer; Optical Sensing; Refractive Index; SEM; Eds
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.5 No.2,
January
27,
2014
ABSTRACT: In this work, a tris(2-aminoethyl)aminodicaboxylate
functionality was substituted for the chloride of polyvinyl-benzyl chloride (PVBC) which was
lightly cross-linked (2%)
with divinyl benzene. The resulting derivatized polymer microspheres were embedded in a hydrogel matrix
of poly vinyl alcohol cross-linked with glutaraldehyde to produce a sensing
membrane. The latter responded selectively to Cu2+ solutions of
different concentration ranges (1 × 10-4 M to 1 × 10-6 M). The response is based on the
interaction between the metal cations and the negatively charged deprotonated
dicarboxylate functional group, which led to neutralization of the charges. As
a result, an increase in the turbidity of the sensing membrane occurred which
is attributed to a change in the refractive index of the derivatized polymer microspheres
relative to that of the hydrogel. The change in the turbidity of the sensing
membrane was measured as absorbance using a conventional spectrophotometer. It
was found that Cu2+ ions bind to the aminodicarboxylated-polymer with a formation constant, Kf, of 1 ×
105 M-1. SEM, Eds and IR analyses were performed on the
aminodicarboxylated microspheres and their Cu2+ complex.