title: A novel cysteine sensor based on modification of carbon paste electrode by Fe(II)-exchanged zeolite X nanoparticles.
abstract: An electrochemical sensor based on carbon paste electrode (CPE) modified with iron(II) doped into a synthesized nano-particles of zeolite X (Fe(II)-NX/ZCME) was constructed, which is highly sensitive for detection of cysteine (Cys). The modified electrode showed an excellent electro-activity for oxidation of Cys in phosphate buffer at pH7.4. It has been found that anodic peak potential of Cys oxidation, compared with the unmodified CPE (UCPE), was shifted towards negative values at the surface of the modified electrode under the optimum condition. The peak current increased linearly with the Cys concentration in the wide range of 5.0 × 10(-9)-3.0 × 10(-3) mol L(-1). The very low detection limit was obtained to be 1.5 × 10(-10) mol L(-1). Finally, the modified electrode was used as a selective, simple and precise new electrochemical sensor for the determination of Cys in the real samples, such as pharmaceutical and biological fluids.
authors.affiliation: Department of Chemistry, Shahreza Branch, Islamic Azad University, P.O. Box 311-86145, Shahreza, Isfahan, Iran; Young Researchers and Elite Club, Shahreza Branch, Islamic Azad university, P.O. Box 311-86145, Shahreza, Isfahan, Iran.
authors.forename: Habibeh-Sadat
authors.initials: HS
authors.lastname: Hashemi
authors.affiliation: Department of Chemistry, Shahreza Branch, Islamic Azad University, P.O. Box 311-86145, Shahreza, Isfahan, Iran; Razi Chemistry Research Center (RCRC), Shahreza Branch, Islamic Azad University, Isfahan, Iran. Electronic address: arnezamzadeh@iaush.ac.ir.
authors.forename: Alireza
authors.initials: A
authors.lastname: Nezamzadeh-Ejhieh
authors.affiliation: Department of Chemistry, Shahreza Branch, Islamic Azad University, P.O. Box 311-86145, Shahreza, Isfahan, Iran; Young Researchers and Elite Club, Shahreza Branch, Islamic Azad university, P.O. Box 311-86145, Shahreza, Isfahan, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Karimi-Shamsabadi
mesh_terms: D002244:Carbon / Q000737:chemistry*; D003545:Cysteine / Q000032:analysis* / Q000652:urine; D055664:Electrochemical Techniques; D004566:Electrodes; D005296:Ferrous Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009824:Ointments / Q000737:chemistry; D010084:Oxidation-Reduction; D017641:Zeolites / Q000737:chemistry*
chemical_list: D005296:Ferrous Compounds; D009824:Ointments; D017641:Zeolites; D002244:Carbon; D003545:Cysteine
keywords: Carbon paste; Cysteine; Nanoparticles; Voltammetry; Zeolite X; Zeolite modified electrode