title: Highly selective electrochemical biosensor for the determination of folic acid based on DNA modified-pencil graphite electrode using response surface methodology.
abstract: An electrochemical DNA biosensor was proposed as a screening device for the rapid analysis of folic acid using a pencil graphite electrode modified with salmon sperm ds-DNA. At first, immobilization of the ds-DNA on pencil graphite electrode was optimized using response surface methodology. Solution pH, DNA concentration, time of DNA deposition and potential of deposition was optimized each at three levels. The optimum combinations for the reaction were pH 4.8, DNA concentration of 24 μg mL(-1), deposition time of 304 s, and deposition potential of 0.60 V, by which the adenine signal was recorded as 3.04 μA. Secondly the binding of folic acid to DNA immobilized on a pencil graphite electrode was measured through the variation of the electrochemical signal of adenine. Folic acid could be measure in the range of 0.1-10.0 μmol L(-1) with a detection limit of 1.06×10(-8) μmol L(-1). The relative standard deviations for ten replicate differential pulse voltammetric measurements of 2.0 and 5.0 μmol L(-1) folic acid were 4.6% and 4.3%, respectively. The biosensor was successfully used to measure folic acid in different real samples.
authors.affiliation: Department of Food Science and Technology, College of agriculture, Isfahan University of Technology, Isfahan 84156-83111, Iran.
authors.forename: Leila
authors.initials: L
authors.lastname: Mirmoghtadaie
authors.forename: Ali A
authors.initials: AA
authors.lastname: Ensafi
authors.forename: Mahdi
authors.initials: M
authors.lastname: Kadivar
authors.forename: Parviz
authors.initials: P
authors.lastname: Norouzi
mesh_terms: D000225:Adenine / Q000032:analysis; D000704:Analysis of Variance; D015374:Biosensing Techniques / Q000295:instrumentation*; D002138:Calibration; D004247:DNA / Q000737:chemistry*; D004563:Electrochemistry / Q000295:instrumentation*; D004566:Electrodes; D005433:Flour / Q000032:analysis; D005492:Folic Acid / Q000032:analysis*; D006108:Graphite / Q000737:chemistry*; D006147:Guanine / Q000032:analysis; D010084:Oxidation-Reduction; D013056:Spectrophotometry, Ultraviolet; D013223:Statistics as Topic; D014908:Triticum / Q000737:chemistry
chemical_list: D006147:Guanine; D006108:Graphite; D004247:DNA; D005492:Folic Acid; D000225:Adenine
keywords: Electrochemical DNA biosensor; Folic acid; RSM optimization; Voltammetry