title: Polyaniline/graphene quantum dot-modified screen-printed carbon electrode for the rapid determination of Cr(VI) using stopped-flow analysis coupled with voltammetric technique.
abstract: Polyaniline/graphene quantum dots (PANI/GQDs) were used to modify a screen-printed carbon electrode (SPCE) in a flow-based system. A method for rapidly determining the Cr(VI) concentrations by using stopped-flow analysis has been developed using an Auto-Pret system coupled with linear-sweep voltammetry using the PANI/GQD-modified SPCE. The GQDs, synthesized in a botton-up manner from citric acid, were mixed with aniline monomer in an optimized ratio. The mixture was injected into an electrochemical flow cell in which electro-polymerization of the aniline monomer occurred. Under conditions optimized for determining Cr(VI), wide linearity was obtained in the range of 0.1-10 mg L(-1), with a detection limit of 0.097 mg L(-1). For a sample volume of 0.5 m L, the modified SPCE can be used continuously with a sample-throughput of more than 90 samples per hour. In addition, this proposed method was successfully applied to mineral water samples with acceptable accuracy, and the quantitative agreement was accomplished in deteriorated Cr-plating solutions with a standard traditional method for Cr(VI) detection.
authors.affiliation: Electrochemistry and Optical Spectroscopy Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok 10330, Thailand.
authors.forename: Eakkasit
authors.initials: E
authors.lastname: Punrat
authors.affiliation: Electrochemistry and Optical Spectroscopy Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok 10330, Thailand; Program in Biotechnology, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok 10330, Thailand.
authors.forename: Chakkarin
authors.initials: C
authors.lastname: Maksuk
authors.affiliation: Electrochemistry and Optical Spectroscopy Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok 10330, Thailand.
authors.forename: Suchada
authors.initials: S
authors.lastname: Chuanuwatanakul
authors.affiliation: Department of Chemistry, Faculty of Science and Technology, Suan Sunandha Rajabhat University, U-Thong Nok Road, Dusit, Bangkok 10300, Thailand. Electronic address: Wanida.Wo@ssru.ac.th.
authors.forename: Wanida
authors.initials: W
authors.lastname: Wonsawat
authors.affiliation: Electrochemistry and Optical Spectroscopy Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok 10330, Thailand. Electronic address: corawan@chula.ac.th.
authors.forename: Orawon
authors.initials: O
authors.lastname: Chailapakul
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D002857:Chromium / Q000032:analysis* / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004785:Environmental Pollutants / Q000032:analysis* / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D007700:Kinetics; D057230:Limit of Detection; D008900:Mineral Waters / Q000032:analysis; D058105:Polymerization; D011327:Printing; D045663:Quantum Dots / Q000737:chemistry*
chemical_list: D000814:Aniline Compounds; D004785:Environmental Pollutants; D008900:Mineral Waters; C416807:polyaniline; D002857:Chromium; C074702:chromium hexavalent ion; D006108:Graphite
keywords: Chromium(VI); Graphene quantum dot; Polyaniline; Stopped-flow analysis; Voltammetry