Browsing by Author "Chang, Liang-Yu"

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One-Minute Fish Freshness Evaluation by Testing the Volatile Amine Gas with an Ultrasensitive Porous-Electrode-Capped Organic Gas Sensor System
(2017-04-01)
Chang, Liang-Yu
;
Chuang, Ming-Yen
;
Zan, Hsiao-Wen
;
Meng, Hsin-Fei
;
Lu, Chia-Jung
In this work, we successfully demonstrate a fast method to determine the fish freshness by using a sensing system containing an ultrasensitive amine gas sensor to detect the volatile amine gas from the raw fish meat. When traditional titration method takes 4 h and complicated steps to test the total volatile basic nitrogen (TVB-N) as a worldwide standard for fish freshness, our sensor takes 1 min to deliver an electrical sensing response that is highly correlated with the TVB-N value. When detecting a fresh fish with a TVB-N as 18 mg/100 g, the sensor delivers an effective ammonia concentration as 100 ppb. For TVB-N as 28-35 mg/100 g, a well-accepted freshness limit, the effective ammonia concentration is as 200-300 ppb. The ppb-regime sensitivity of the sensor and the humidity control in the sensing system are the keys to realizing fast and accurate detection. It is expected that the results in this report enable the development of on-site freshness detection and real-time monitoring in a fish factory.
Room-temperature-operated organic-based acetone gas sensor for breath analysis
(2018-05-01)
Chuang, Ming-Yen
;
Lin, Yu-Ting
;
Tung, Ting-Wei
;
Chang, Liang-Yu
;
Zan, Hsiao-Wen
The major merits of organic-based sensors include their low cost, room-temperature operation, and small size. However, their sensitivity and selectivity are concerning, especially in the application of breath analysis. In this work, organic-based sensors were developed based on cylindrical nano-pore structures, which enhanced the sensitivity down to ppb levels. The sensing performance was demonstrated both in pure nitrogen and ambient air. The sensor constructed with poly[(9,9-dioctylfluoreny1-2,7-diy1)-co-(4,41(N-(4-sec-butylphenyl)diphenylamine)] (TFB) exhibited a 5% sensing response to 300 ppb of acetone in ambient air. In addition, the sensor's response to other major breath components, including nitric oxide, ethanol, carbon dioxide, and ammonia, was also established. The results showed that the TFB sensor also exhibited a good response to ammonia. Therefore, a humidification tube was designed as an ammonia filter to improve selectivity. The concept of integrating a highly sensitive sensor with a customized sensing system shows promise for medical applications. (C) 2018 Elsevier B.V. All rights reserved.