In plasticized (2-nitro-phenyloctyl ether (o-NPOE)) and polyvinyl chloride (PVC) membrane incorporating (N,N- diethyl-5-(octadecanoylimino)-5H-benzo[a] phenolxazine-9-amine (ETH 5294) and sodium tetraphenyl borate (NaTPB), an ionophore 5-(2,4 -dimethylphenylazo)-6-hydroxy-pyrimidine-2,4-dione (DMPAHPD) form an optical chemical sensor
for zinc determination is ascribed. The sensor response is based on selective complexation
of
Zn
2+
with DMPAHPD in the designed membrane phase, resulting in an ion exchange process between H
in the membrane and Zn2+ in the sample solution. The influences of several experimental parameters, as membrane
composition, pH, and type and concentration of the regenerating reagent, were demonstrated. The sensor has a
response range of 5.0 × 10
9
to 2.5 × 10
5
M Zn
2+
with detection and quantification limits of 1.6 × 10
and
4.9 × 10
9
M, respectively. The response time of 1 min at 0.1 M phosphate buffer solution of pH 5.0 with
recording repeatability and sensor-to sensor reproducibility is reported. The proposed sensor signifies high
selectivity for Zn
2+
over various transition metal ions, alkali, and alkaline earth ions. The sensor membrane can
be simply regenerated with 0.5 M HNO
3
. The sensor has been used to assess Zn
2+
in river, waste, tap, sea, well,
and spring waters samples, serum of diabetic patients, powdered milk, hair, red meat, pharmaceutical formulations,
and
talc
powder
samples.
9
+ |
