04885nas a2200481 a 4500 20260818090754.0 190827s2017 th uu m rtt 0| a1eng d .b12310086 AIT Thesis no.FB-17-07 Kornautchaya Veenuttranon Development of an automatic electrochemical flow system for high throughput determination of total antioxidant capacity in biological materials Pathum Thani, Thailand : Asian Institute of Technology, 2017 90 leaves : ill. + 1 online resource Thesis ; no.FB-17-07 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Food Engineering and Bioprocess Technology, School of Environment, Resources and Development Thesis (M. Sc.) - Asian Institute of Technology, 2017 The aim of this work was to develop a programmable compressed - nitrogen gas flow system combined with electrochemical based assay for assessment of total antioxidant capacity (TAC) using the 2, 2 - diphenyl - 2 - picrylhydrayl hydrate (DPPH{u2022}) solution as a redox indicator on a screen printed carbon electrode ( SPE) . Gallic acid (GA) was chosen as a standard antioxidant. Firstly , the prototype device was designed and fabricated with an internal volume of 1,500 oL . A programmable electronic controlled 3 - way solenoid valve was utilized to control the liquid flow and retention time inside the reaction chamber of the system. A suitable driven pressure for compressed nitrogen gas was 20 kPa which was used to control the volumetric dosage of samples and reagents. There were a good linear relationship between propelled time and volumetric dosage (R 2 > 0.999 ) for all injection ports in which the linear regression equations were used to determine an accurate time for liquid injection . T he electrochemical characterizations of DPPH{u2022} and GA were performed using cyclic voltammetry (CV) , as a result, a suitable applied potential (E) of - 0.05 V was select ed for amperometric determination of TAC. The calibration curve was developed by measuring the constant currents of amperometry ( I ) for different concentration of GA in fixed 0.05 mM DPPH solution, after incubating the mixture for 2 min. One pure compound of ascorbic acid and four liquid food samples (orange juice, pomegranate juice, white wine and green tea) were mixed instead of GA and respective ( I ) were measured to determine the TAC. The results of TAC was then expressed in terms of gallic acid equivalent antioxidant capacity (GEAC). All the above experiments were co - conducted with the spectrophotometric analysis and results were compared. A good linear correlation (R 2 = 0.996 ) was obtained between electrochemical test within flow mixing system and conventional method of DPPH{u2022} scavenged by ascorbic acid, and two methods could be used interch ange (slope = 0.951 ). IC 50 and TAC of four samples were investigated by dif ferentiating the concentration and there was no significant difference (p> 0. 05) between the two methods. Antioxidants Biotechnology Biomaterials Electrochemical apparatus Loc Thai Nguyen, Chairperson Anal, Anil Kumar, Examination Committee Sadiq, Muhammad Bilal, Examination committee RTG Fellowship, Scholarship donor Asian Institute of Technology. Thesis ; no. no.FB-17-07 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B02864 .b12310086 mnait m 240422 0 190827 m a m 0 000:001:PDF:b1231008:004339:0:0:0:0:0:0 Click to view Abstract n mnait mnait mnarc mnarc 40 61 20 Barcode : 30050120894406 CREATED : 2019-05-23 RECORD # : i13188598 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : - CREATED : 2019-05-23 RECORD # : i13188604 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050120955470 CREATED : 2019-08-27 RECORD # : i13213921 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050120955447 CREATED : 2019-08-27 RECORD # : i13213933 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 29100 29100 0 0 0 0 MAIN MAIN mnarc 2026-08-18 0 AIT Thesis no.FB-17-07 30050120894406 2026-08-18 09:07:54 1 2026-08-18 40 0 0 0 0 MAIN MAIN mnarc 2026-08-18 0 AIT Thesis no.FB-17-07 2026-08-18 09:07:54 2026-08-18 61 0 0 0 0 MAIN MAIN mnait 2026-08-18 50.00 0 AIT Thesis no.FB-17-07 30050120955470 2026-08-18 09:07:54 1 2026-08-18 20 0 0 0 0 MAIN MAIN mnait 2026-08-18 50.00 0 AIT Thesis no.FB-17-07 30050120955447 2026-08-18 09:07:54 2 2026-08-18 20