title: Application of a new iridium complex as a chemiluminescence reagent for the determination of tryptophan.
abstract: It was found that a novel iridium complex, [(dpci)(2)Ir(bvbbi)](PF(6)) (dpci = 3,4-diphenylcinnoline, bvbbi = N,N'-bivinyester-(1)H,(1)'H-[2,2'] bibenzimidazole), with Ce(IV) in the presence of sodium sulfite can induce a great chemiluminescence (CL) emission. More importantly, a rapid and sensitive CL method for the determination of tryptophan coupled with a flow-injection analysis (FIA) technique has been developed based on the inhibition effect of the tryptophan to the CL emission of [(dpci)(2)Ir(bvbbi)](PF(6))-Ce(IV)-SO(3)(2-) system. Under the optimum conditions, the decreased CL intensity is proportional with the concentration of tryptophan in the range of 5.0 × 10(-7) to 2.0 × 10(-5) mol L(-1), and the detection limit is 8.2 × 10(-8) mol L(-1) (3σ). The relative standard deviation (RSD) for 11 parallel measurements of 1.0 × 10(-5) mol L(-1) tryptophan is 2.7%. The proposed method has been applied successfully for the determination of tryptophan in its pharmaceutical formulations. Moreover, the possible inhibition mechanism of tryptophan on [(dpci)(2)Ir(bvbbi)](PF(6))-Ce(IV)-SO(3)(2-) CL system was briefly discussed.
authors.affiliation: School of Chemistry and Chemical Engineering, Institution of Molecular Engineering and Applied Chemistry, Anhui University of Technology, Maanshan, PR China. ahutsjz@126.com
authors.forename: Fanghui
authors.initials: F
authors.lastname: Wu
authors.forename: Bihai
authors.initials: B
authors.lastname: Tong
authors.forename: Qianfeng
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D017022:Flow Injection Analysis / Q000295:instrumentation; D005456:Fluorescent Dyes / Q000737:chemistry*; D007495:Iridium / Q000737:chemistry*; D008163:Luminescent Measurements / Q000295:instrumentation; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D014364:Tryptophan / Q000032:analysis*
chemical_list: D005456:Fluorescent Dyes; D009942:Organometallic Compounds; D007495:Iridium; D014364:Tryptophan