title: Ultra-high performance liquid chromatographic determination of antioxidants in teas using inkjet-printed graphene-polyaniline electrode.
abstract: A development of ultra-high performance liquid chromatographic coupled with a novel inkjet-printed conductive ink-modified electrode for a fast and simultaneous determination of polyphenolic antioxidants was achieved. Two printing techniques were selected for fabrication and modification including (i) an in-house screen-printing method and (ii) an inkjet-printing method, respectively. A conductive ink containing graphene and polyaniline nanocomposite (G-PANI) was precisely casted onto the surface of screen-printed carbon electrode (SPCE) using a dimatix inkjet material printer. Compared to a bare SPCE, the G-PANI-modified screen-printed carbon electrode (G-PANI/SPCE) exhibited higher electrochemical sensitivity with increase (2-4 times) of peak current of each antioxidant. Moreover, four antioxidants were successfully separated and determined within 3 min using a reverse phase ultra-high performance liquid chromatography (UHPLC) with a mobile phase containing phosphate buffer and acetonitrile (90:10 v/v). Under an optimal detection potential at +1.2V vs. Ag/AgCl, linear calibrations and limits of detection (S/N=3) for antioxidants were found to be 0.01-10 µg mL(-1) and 1.38-1.94 ng mL(-1), respectively. Finally, this proposed method has been successfully used for the determination of antioxidants in tea samples, the results obtained from our presented method were within a highly good agreement those obtained from a standard UHPLC-UV method.
authors.affiliation: Electrochemistry and Optical Spectroscopy Research Unit (EOSRU), Department of Chemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand; Center of Excellence on Petrochemical and Materials Technology, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand.
authors.forename: Chayanee
authors.initials: C
authors.lastname: Bardpho
authors.affiliation: Electrochemistry and Optical Spectroscopy Research Unit (EOSRU), Department of Chemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand.
authors.forename: Poomrat
authors.initials: P
authors.lastname: Rattanarat
authors.affiliation: Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit, Bangkok 10110, Thailand.
authors.forename: Weena
authors.initials: W
authors.lastname: Siangproh
authors.affiliation: Electrochemistry and Optical Spectroscopy Research Unit (EOSRU), Department of Chemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand; Center of Excellence on Petrochemical and Materials Technology, Chulalongkorn University, Patumwan, Bangkok 10330, Thailand. Electronic address: corawon@chula.ac.th.
authors.forename: Orawon
authors.initials: O
authors.lastname: Chailapakul
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D000975:Antioxidants / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D055664:Electrochemical Techniques / Q000379:methods*; D006108:Graphite / Q000737:chemistry*; D011327:Printing / Q000295:instrumentation / Q000379:methods*; D013662:Tea / Q000737:chemistry*
chemical_list: D000814:Aniline Compounds; D000975:Antioxidants; D013662:Tea; C416807:polyaniline; D006108:Graphite
keywords: Antioxidants; Electrochemical detection; Graphene; Inkjet-printing; Polyaniline; Polyphenolic; UHPLC