New PVC Nitrate-Selective Electrode: Application to Vegetables
and Mineral Waters
P. Kong Thoo Lin
A. N. Araujo
M. C. B. S. M. Montenegro
R. Pérez-Olmos
10.1021/jf049227u.s001
https://acs.figshare.com/articles/journal_contribution/New_PVC_Nitrate_Selective_Electrode_Application_to_Vegetables_and_Mineral_Waters/3303337
The paper refers the analytical potentialities of the oxa-azamacrocycles as potentiometric ionophores
for the construction of electrodes selective to nitrate. Afterward, the membrane selective to nitrate is
designed and optimized using a [3.3.3.3]oxazane as an ionophore. The membrane was prepared
using dibutylphthalate as a solvent mediator, tetraoctylammonium as a lipophilic membrane additive,
and poly(vinyl chloride (PVC) as a polymeric matrix, applied directly onto a conductive graphite/epoxy resin support. The electrodes presented a slope of 60 ± 0.1 mV log<sup>-1</sup>, a low limit of linear
response of 4.2 × 10<sup>-6</sup> mol L<sup>-1</sup>, a useful lifetime of 1 year, and improved selectivity characteristics
when compared with other nitrate electrodes. The good working characteristics of this electrode,
constructed without inner-reference solution, made possible its application to the determination of
nitrate in different types of vegetables and bottled mineral waters without the use of a conditioning
solution. The application of a significant <i>F</i> test proved that the results obtained were similar to those
attained by application of the brucine spectrophotometric method adopted as a reference technique.
Linear regression analysis also showed good agreement between the results obtained by the proposed
method and the reference one.
Keywords: Oxa-azamacrocycles; ionophore; nitrate-selective electrode; vegetables; water
2005-01-26 00:00:00
nitrate electrodes
selectivity characteristics
conditioning solution
method
1 year
F test
Mineral Waters
mineral waters
lipophilic membrane additive
Linear regression analysis
application
reference technique
potentiometric ionophores