Browsing by Author "Jang, Hung-Der"

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A rapid and selective method for monitoring the growth of coliforms in milk using the combination of amperometric sensor and reducing of methylene blue
(2009-09-07)
Lee, Yuan-Geuy
;
Wu, Hung-Yi
;
Hsu, Chuan-Liang
;
Liang, Hong-Jen
;
Yuan, Chiun-Jye
A novel method for monitoring the growth of coliforms in milk was developed based on measuring the current change in an amperometric sensor. The sensor consists of a circuit with a homemade potentiostat and a pair of electrodes. The electrode was immersed in milk samples containing methylene blue with various concentrations of bacterial inoculums. The microbial metabolism led to the reduction of methylene blue resulting in a change of current. The time required to identify readily detectable change (detection time, DT) provided an approximate measurement of the amount of microorganisms in the initial inoculums. The sensor system used in this study has the selectivity towards coliform bacteria such as Escherichia coli and Enterobacter aerogenes. The calibration curve of DT against concentration of coliform showed a linear correlation coefficient (R(2) = 0.9192) over the range of 10(2)-10(8) CFU/mL. The sensor was able to detect the coliform bacteria at initial concentrations of 10(5) CFU/mL within 6 h, making it suitable for use in real-time monitoring of bacterial growth. This system has potential application in the detection of coliform concentration in milk at dairy farms when a proper selective media is designed. (C) 2009 Elsevier B.V. All rights reserved.
Improvement of the inter-electrode reproducibility of screen-printed carbon electrodes by oxygen plasma etching and an image color level method for quality control
(2011-10-10)
Chang, Yi-Huang
;
Hsu, Chuan-Liang
;
Yuan, Chiun-Jye
;
Tang, Shu-Fan
;
Chiang, Hui-Jean
Screen-printed carbon electrodes (SPCEs) were selectively etched by oxygen plasma. The coefficient of variance (CV) of inter-electrode reproducibility was reduced from 21.6 to 4.6. Studies of the surface by color-level-indexing histogram analysis. scanning electronic microscopy (SEM) and resistance revealed that the inter-electrode reproducibility correlated with complete etching of the resin binder from the SPCE surface. The quality of the electrode was differentiated by this color level index analysis. This technique has great potential for application in on-line quality control of the SPCE plasma-treating process when integrated with suitable image processing software. (C) 2011 Elsevier B.V. All rights reserved.