title: Selective recognition of D-tryptophan from d/l-tryptophan mixtures in the presence of Cu(II) by electropolymerized L-lysine film.
abstract: Selective recognition of D-tryptophan (D-Trp) in the presence of Cu(II) was investigated at poly-L-lysine (p-l-Lys) film using electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). p-l-Lys film was immobilized on a glassy carbon electrode (GCE) by cyclic voltammetry between 0.0 and 1.9 V in 20 mM phosphate buffer solution (pH 8.6). After the p-l-Lys/GCE electrode was incubated with D-Trp solution containing Cu(II) ions, obvious enhancement of electron transfer resistance and decrease of voltammetric current could be observed. If D-Trp was replaced by L-tryptophan (l-Trp), there was no apparent resistance and current changes. Moreover, no resistance and current changes could be found in the absence of Cu(II). It may be due to the formation of Cu complex with L-lysine and D-tryptophan. Finally, this method was successfully applied to monitoring enantiomeric composition of the D-Trp and l-Trp mixtures.
authors.affiliation: Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing 100190, China. Electronic address: fwang@whu.edu.cn.
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.affiliation: Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China.
authors.forename: Wencheng
authors.initials: W
authors.lastname: Gong
authors.affiliation: Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Wang
authors.affiliation: Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing 100190, China. Electronic address: chenzl@whu.edu.cn.
authors.forename: Zilin
authors.initials: Z
authors.lastname: Chen
mesh_terms: D003300:Copper / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D007477:Ions / Q000737:chemistry; D011107:Polylysine / Q000737:chemistry*; D013237:Stereoisomerism; D014364:Tryptophan / Q000032:analysis*
chemical_list: D007477:Ions; D011107:Polylysine; D003300:Copper; D014364:Tryptophan
keywords: Cu(II); Electropolymerization; Voltammetry; d-tryptophan; l-Lysine