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Updated: May 31, 2026
07:58
A Polyaniline-based Sensor of Nucleic Acids
Published on: November 1, 2016
Anion recognition through amide-based dendritic molecule: a poly(vinyl chloride) based sensor for nitrate ion
Vinod Kumar Gupta1, Lok Pratap Singh, Sudeshna Chandra
1Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee, India. vinodfcy@iitr.ernet.in
Talanta
|July 6, 2011
Summary
This study developed a novel nitrate ion-selective electrode using poly(vinyl chloride) membranes. The optimized electrode demonstrates high selectivity and a low detection limit for nitrate determination in wastewater.
Area of Science:
- Electrochemistry
- Analytical Chemistry
- Materials Science
Background:
- Nitrate contamination in water poses environmental and health risks.
- Development of selective and sensitive sensors for nitrate detection is crucial for water quality monitoring.
- Ion-selective electrodes (ISEs) offer a promising platform for electrochemical sensing.
Purpose of the Study:
- To develop and characterize a novel nitrate ion-selective electrode.
- To optimize the membrane composition for enhanced performance.
- To evaluate the electrode's applicability in real-world water samples.
Main Methods:
- Preparation of poly(vinyl chloride) (PVC)-based membranes incorporating N,N-bis-succinamide dendritic molecules, tetrabutyl ammonium bromide (TBAB), and plasticizers (DBP, DOP, DBBP, CN).
- Optimization of membrane composition (PVC-TBAB-DBP ratio 1:33:1:65 w/w).
- Electrochemical characterization including response linearity, detection limit, Nernstian compliance, pH range, response time, and selectivity studies.
Main Results:
- The optimized electrode exhibited a linear response to nitrate ions with a detection limit of 3.9 × 10⁻⁵ M.
- Nernstian behavior (57.0 mV/decade) was observed over a wide pH range (2.8–9.6) with a rapid response time (~20s).
- High selectivity for nitrate over various interfering anions (selectivity coefficient ~0.001) was achieved.
Conclusions:
- The developed N,N-bis-succinamide-based dendritic molecule electrode offers a cost-effective and easy-to-prepare solution for nitrate sensing.
- The electrode demonstrates excellent performance characteristics, including sensitivity, selectivity, and stability over 45 days.
- The proposed electrode is analytically useful for determining nitrate levels in wastewater samples.
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Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.
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Nitrous acid and nitric acids are two types of acids containing nitrogen, among which nitrous acid is weaker than nitric acid. Nitrous acid with a pKa value of 3.37 ionizes in water to give a nitrite ion and the hydronium ion.
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...
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