• KSBB Journal
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• v.16 no.5
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• pp.459-465
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• 2001

The on-line monitoring technique for the concentrations fo glucose and starch by FIA(Flow Injection Analysis)system was studied. Glucose oxidase(GOD) and amyloglucosidase(AMG) were immboilized on VA-Fpoxy carrier and integrated into the FLA system. The pH, buffer flow rate and temperature were optimized and the effects of salts and metabolites dissolved in the sample on the activity of immobilized enzyme were investigated. GOD-FIA and AMG/GOD-FIA were applied for the on-line monitoring of the glucose and starch in a simulated bioprocess. The on-line measurements of glucose concentrations by GOD-FIA agreed with off-line data well and the AMG/GOD-FIA with single cartidge system took and advantage over the FIA system with two separated cartridges for the on-line monitoring of starch concentrations.

• KSBB Journal
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• v.13 no.3
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• pp.244-250
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• 1998

Flow-injection analysis (FIA) for on-line monitoring of glucose and acetate are described and employed in E.coli fermentation process. Glucose oxidase (GOD) for the detection of glucose is immobilized on epoxy polymer support, which is packed in a small cartirdge, and applied to a GOD-FIA system. The detection of acetate is based on the inhibition of acetate to the oxidation of sarcosine by sarcosine oxidase (SOD). SOD is also immobilized on epoxy polymer support and used for a SOD-FIA system. GOD-FIA system is characterized as well as SOD-FIA system by the investigation of the effects of pH, temperature and metabolites in samples on the peak height. GOD-FIA and SOD-FIA systems were also applied for on-line On-line measurements buy FIA measurements by FIA were in god agreement with off-line measurements.

• Preventive Nutrition and Food Science
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• v.4 no.1
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• pp.79-83
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• 1999

A potentiometric biosensor employing a CO3-2 ion-selective electrode(ISE) and malic enzyme immobilization in al flow injection analysis (FIA) system was constructed. Analytical parameters were optimized for L-malate determination . The CO3-2 -ISE-FIA system was composed of a pump, an injector, a malic enzyme (EC1.1.1.40) reactor, a CO3-2 ion-selective electrode, a pH/mV meter and a recorder. Cofactor NADP was also injected with substrate for theenzyme reaction into the system. Optimized analytical parameters for L-malate determination in the CO3-2 ISE-FIA system were as follows ; flow rate, 14.5ml/hr ; sample injection volume, 100ul; enzyme loading in the reactor, 20 units ; length of the enzyme reactor , 7 cm ; tubing length form the enzyme reactor to the detector as a geometric factor in FIA, 15 cm . The response time for measuring the entire L-malate concentration range (10-2 ~10-5 mol/L ; 4 injections )was <15minutes . In this CO3-2 -ISE-FIA system, the potential differences due to th eformation of CO3-2 by the reaction of malic enzyme on L-malate were correlated to L-malate concentration in the range of 10-2 ~10-5mol/L ; the detection limit was 10-5 mol/L. This potentionmetric CO3-2 ISE--FIA system was found to be useful for L-malate measurement.

• KSBB Journal
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• v.18 no.5
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• pp.377-384
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• 2003

On-line monitoring techniques for fumaric acid and succinic acid were developed by flow injection analysis (FIA). For the determination of fumaric acid, two enzymes, fumarase and malic dehydrogenase were immobilized on VA-epoxy Biosynth E3-carrier and integrated into a FIA-system with a fluorescence detector. For the analysis of succinic acid, isocitrate lyase and isocitrate dehydrogenase were also immobilized on VA-epoxy polymer support and used in a FIA system. The immobilized enzymes in two FIA systems were characterized systematically, e.g. optimum pH and temperature, inhibitory effects etc. Two FIA systems were also used to on-line monitor the concentrations of fumaric acid and succinic acid in biotechnological processes. Good agreement between on-line monitored data and off-line data measured by HPLC showed extensive application of the FIA systems in bioprocesses.

• KSBB Journal
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• v.8 no.4
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• pp.328-335
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• 1993

A flow injection analysis(FIA) system was developed for the determination of cholesterol using immobilized cholesterol oxidase and cholesterol ester hydrolase. The enzymes were immobilized on controlled pore galas(CPG) by the glutaraldehyde method. The glass colunms packed with immobilized enzymes were found to contain 3-5 I.U. for each enzyme. A hydrogen peroxide sensitive electrode was contructed and applied to the FIA system. The operational conditions for FIA response were investigated and optimized with variation of sampling volume, flow rate and composition of carrier solution. The FIA response were linear upto 60 and 400mg/m1 for free cholesterol and cholesterol ester, respectively. All samples were analyzed with a good precision (<2.5% CV) and accuracy. 23 samples were mea sured succesively within about an hour. Intermittent assays of more than 500 times caused 50% decrease in response sensitivity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.5
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• pp.965-967
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• 2000

An on-line FIA system in place of traditional Conway method was used for quicker and simpler analysis of volatile basic nitrogen of pork. The on-line system was developed by connecting an FIA apparatus with an ammonia electrode as a detector to a personal computer. The data from Conway method and from the on-line FIA system were in good agreement and the correlation coefficient was 0.981. One sample could be analyzed in about 4 min.

• Journal of Electrochemical Science and Technology
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• v.11 no.3
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• pp.248-256
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• 2020

In this study, pyrocatechol violet (Pcv) is proposed for the first time as an efficient electrocatalyst for oxidation of sulfide and flow injection analysis (FIA) of sulfide. A graphite pencil electrode (GPE) was modified with Pcv via immersion of the GPE into 0.01 M Pcv solution for 15 min. Cyclic voltammograms (CVs) demonstrated that Pcv/GPE exhibits a good electrocatalytic performance due to shift in the potential from +400 at bare GPE to +70 mV at Pcv/GPE and obtaining an enhancement in the peak current compared with the bare GPE. A linear range between 0.25 and 250 μM sulfide with a detection limit of 0.07 μM was obtained from the recorded current-time curves in Flow Injection Analysis (FIA) of sulfide. Sulfide in water samples was also successfully determined using the proposed FI amperometric methods.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.3
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• pp.156-165
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• 2004

Concentrations of substrates, glucose, and ammionia in biological processes have been on-line monitored by using glucose-flow injection (FIA) and ammonia-FIA systems. Based on the on-line monitored data the concentrations of substrates have been controlled by an on-off controller, a PID controller, and a neural network (NN) based controller. A simulation program has been developed to test the control quality of each controller and to estimate the control parameters. The on-off controller often produced high oscillations at the set point due to its low robustness. The control quality of a PID controller could have been improved by a high analysis frequency and by a short residence time of sample in a FIA system. A NN-based controller with 3 layers has been developed, and a 3(input)-2(hidden)-1(output) network structure has been found to be optimal for the NN-based controller. The performance of the three controllers has been tested in a simulated process as well as in a cultivation process of Saccharomyces cerevisiae, and the performance has also been compared to simulation results. The NN-based controller with the 3-2-1 network structure was robust and stable against some disturbances, such as a sudden injection of distilled water into a biological process.

• KSBB Journal
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• v.17 no.4
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• pp.339-344
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• 2002

Flow injection analysis technique for monitoring of xylitol concentrations in biological processes has been developed using xylitol oxidase (XYO) immobilized on VA-Epoxy Biosynth carrier. The immobilized XYO cartridge has been integrated into a FIA system with an oxygen electrode and systematically investigated with regards to the factors which can affect the activity of the immobilized XYO, such as pH, temperature, salt concentration etc. The activity of the immobilized XYO increased with the temperature ($19.0 - 29.0^{circ}C$) and sample injection volume ($75-250\muL$) and molarity of potassium phosphate buffer (0.1-1 M), but it reached the highest value at pH 8.5. The XYO-FIA system has been also applied for on-line monitoring of xylitol concentrations in a reactor and showed good operational stability and agreement with off-line data measured with HPLC.

• KSBB Journal
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• v.15 no.4
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• pp.388-392
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• 2000

An on-line glucose flow injection analysis system was developed and used for the automatic analysis and addition of glucose in the cultivationof a Saccharomyces cerevisiae in a korean paper digestion wastewater in order to increase the cell concentration. The system was composed of a ceramic sampler a sampling valve an injection valve an immobilized glucose oxidase column a debbble a flow cell with platinum electrodes a potentiostat a computer and interface system and tubing pumps. The glucose concentration of the wastewater medium was mainitained at the low concentration of $176{\pm}31 mg/L$ with the on-line FIA system and by adding glucose and $>(NH_4)_2S0_4$ the cell concentration as total cell count can be increased by 3.1times.