Korkut, Şeyda | Kılıç, Muhammet Samet | Uzunçar, Sinan | Hazer, Baki

Article | 2016 | Analytical Letters49 ( 14 ) , pp.2322 - 2336

A carboxylated poly(styrene-b-isoprene-b-styrene) triblock copolymer was synthesized for the construction of an enzymatic fuel cell. Glucose oxidase and bilirubin oxidase were chemically immobilized via the carboxylated functional groups of the polymer. The enzymatic fuel cell working electrodes were modified with graphene to accelerate the electron transfer rate of the system. Essential design and operational parameters were carefully optimized for improving the power of the enzymatic fuel cell. A power density of 20 µW cm-2 with only 4 µg of immobilized bilirubin oxidase was generated from 30 mM glucose at 0.72 V. The improved enz . . .ymatic fuel cell was tested in a plant leaf. A power density of 14 nW cm-2 was generated with glucose produced by photosynthesis reactions conducted during 30 min in the leaf. © 2016, Taylor & Francis Group, LLC Daha fazlası Daha az

Ünsal, Yunus Emre | Soylak, Mustafa | Tüzen, Mustafa | Hazer, Baki

Article | 2015 | Analytical Letters48 ( 7 ) , pp.1163 - 1179

A separation and preconcentration method has been established based on solid phase extraction of Fe(III), Cu(II) and Pb(II) as their 2-(5-Bromo-2-pyridylazo)-5-diethylamino-phenol (5-Br-PADAP) chelates adsorbed on polyhydroxybutyrate-b-polydimethyl siloxane. Several analytical conditions including pH, amount of (5-Br-PADAP), eluent type and volume, sample volume, and flow rates were investigated. The effects of foreign ions on the recovery of the analytes were also studied. The detection limits for Cu(II), Fe(III), and Pb(II) were 1.9, 2.2, and 2.5 µg per liter, respectively. Enrichment factors for Cu(II), Fe(III), and Pb(II) were 1 . . .50, 200, and 80, respectively. The adsorption capacity of the polymer for Cu(II) and Pb(II) studied was 10.2 and 17.2 milligrams per gram respectively. Relative standard deviation was 4%. Standard Reference Material (SRM 1577B Bovine liver), International Atomic Energy Agency (IAEA 336 Lichen), and Certified Reference Waters for Trace Elements (TMDA 51.3 Fortified lake water) were used for the validation of the method. Optimized procedure was applied for the determination of analyte elements in various cosmetic products, hair brilliantine and gel, water, soil, and food samples from Turkey. © 2015, Copyright © Taylor & Francis Group, LLC Daha fazlası Daha az

Kılıç, Muhammet Samet | Korkut, Şeyda | Hazer, Baki

Article | 2014 | Analytical Letters47 ( 6 ) , pp.983 - 995

A recently synthesized polypropylene-g-polyethylene glycol polymer was used for the first time as the working electrode of a fuel cell. Electrodes were prepared for unmediated and mediated enzymatic reactions including ferrocene as the mediator. Glucose oxidase and bilirubin oxidase was used as the anodic and cathodic enzymes for the working electrodes, respectively. The biofuel cell was operated using glucose as the fuel in a single-compartment and membrane-less cell. Electrochemical results demonstrated that the catalytic efficiency of the ferrocene based cathode was approximately 100-fold higher than that of an unmediated cathode . . .. The mediated fuel cell electrodes yielded a power density of 65 nW/cm2 at a cell potential of +560 mV. © 2014 Copyright Taylor & Francis Group, LLC Daha fazlası Daha az