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Sol-gel-based optical sensor for the detection of aqueous amines
Spela Mojca Korent1, Aleksandra Lobnik, Gerhard J Mohr
1Center of Sensor Technology, Faculty of Mechanical Engineering, University of Maribor, Smetanova 17, 2000 Maribor, Slovenia.
Analytical and Bioanalytical Chemistry
|March 23, 2007
Summary
This study developed a novel optical sensor for detecting aqueous amines using chromoionophore XV within sol-gel thin films. Base-catalyzed sensor layers demonstrated rapid, reversible detection of propylamine, achieving a 0.1 mmol L(-1) detection limit.
Area of Science:
- Chemical Sensors
- Materials Science
- Analytical Chemistry
Background:
- Developing selective and sensitive optical sensors is crucial for detecting aqueous amines.
- Sol-gel technology offers a versatile platform for creating functional thin films for sensing applications.
- Protecting sensor layers from environmental interference is essential for reliable measurements.
Purpose of the Study:
- To create and characterize an optical sensor for aqueous amine detection.
- To investigate the influence of sol-gel catalysis on sensor performance.
- To evaluate the sensor's response time, regeneration time, and detection limit.
Main Methods:
- Incorporation of chromoionophore XV into sol-gel thin films using acid- and base-catalyzed processes.
- Preparation of methyltriethoxysilane (MTriEOS) modified ormosil layers.
- Coating sensor layers with a protective polytetrafluoroethylene (PTFE) layer.
- Utilizing a flow-through cell in reflection mode for measurements.
Main Results:
- Base-catalyzed sensor layers (pH 3 and 13) exhibited significant signal changes upon exposure to amines, unlike acid-catalyzed layers.
- The optimal base-catalyzed sensor (L3, pH 13) showed a response time of 20-30 s for propylamine.
- A detection limit of 0.1 mmol L(-1) was achieved, with reproducible and reversible sensor responses.
- The sensor layers allowed for dry storage.
Conclusions:
- Base-catalyzed sol-gel films incorporating chromoionophore XV are effective for optical detection of aqueous amines.
- The developed sensor offers rapid response, reversibility, and a low detection limit.
- The protective PTFE layer enhances sensor stability by preventing ion and light interference.
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