title: Polymer modified glassy carbon electrode for the electrochemical determination of caffeine in coffee.
abstract: 4-Amino-3-hydroxynaphthalene sulfonic acid (AHNSA) was electropolymerized on a glassy carbon electrode. The deposited film showed electrocatalytic activity towards the oxidation of caffeine. The polymer-modified electrode showed high sensitivity, selectivity and stability in the determination of caffeine in coffee. The peak current increased linearly with the concentration of caffeine in the range of 6 × 10(-8) to 4 × 10(-5) mol L(-1), with a detection limit of 1.37 × 10(-7) mol L(-1) (LoD = 3δ/slope). Analysis of caffeine in coffee was affected neither by sample matrices nor by structurally similar compounds. Recoveries ranging between 93.75 ± 2.32 and 100.75 ± 3.32 were achieved from coffee extracts indicating the applicability of the developed method for real sample analyses.
authors.affiliation: Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia. maerega@yahoo.com
authors.forename: Meareg
authors.initials: M
authors.lastname: Amare
authors.forename: Shimelis
authors.initials: S
authors.lastname: Admassie
mesh_terms: D002110:Caffeine / Q000032:analysis* / Q000737:chemistry; D002138:Calibration; D002244:Carbon / Q000737:chemistry*; D003069:Coffee / Q000737:chemistry*; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D005504:Food Analysis / Q000295:instrumentation / Q000379:methods*; D005898:Glass / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D009282:Naphthalenesulfonates / Q000737:chemistry*; D058105:Polymerization; D011108:Polymers / Q000737:chemistry*; D013997:Time Factors
chemical_list: D003069:Coffee; D009282:Naphthalenesulfonates; D011108:Polymers; D002110:Caffeine; D002244:Carbon