title: The fluorescence and resonance Rayleigh scattering spectra study on the interactions of palladium (II)-Nootropic chelate with Congo red and their analytical applications.
abstract: A highly sensitive detection approach of resonance Rayleigh scattering spectra (RRS) is firstly applied to analyzing nootropic drugs including piracetam (PIR) and oxiracetam (OXI). In HCl-NaAc buffer solution (pH=3.0), the OXI chelated with palladium (II) to form the chelate cation [Pd2·OXI]2+, and then reacted with Congo red (CGR) by virtue of electrostatic attraction and hydrophobic force to form binary complex [Pd2·OXI]. CGR2, which could result in the great enhancement of RRS. The resonance Rayleigh scattering signal was recorded at λex=λem=375nm. This mixture complex not only has higher RRS, but also makes contribution to significant increase of fluorescence, and the same phenomena also were discovered in PIR. The enhanced RRS intensity is in proportion to the PIR and OXI concentration in the range of 0.03-3.0μgmL-1, and the detection limit (DL) of RRS method for PIR and OXI is 2.3ngmL-1and 9.7ngmL-1. In addition, the DL of fluorescence method for PIR and OXI is 8.4μgmL-1and 19.5μgmL-1. Obviously, the RRS is the highly sensitive method, and the recoveries of the two kinds of nootropic drugs were range from 100.4% to 101.8.0% with RSD (n=5) from 1.1% to 3.1% by RRS method. This paper not only investigated the optimum conditions for detecting nootropics with using RRS method, but also focused on the reasons for enhancing RRS intensity and the reaction mechanism, which in order to firm and contract the resultant. Finally, The RRS method has been applied to detect nootropic drugs in human urine samples with satisfactory results.
authors.affiliation: Chemistry and Chemical Engineering, Southwest University, No. 2 Tiansheng Road, Beibei District, Chongqing 400715, PR China.
authors.forename: Fang
authors.initials: F
authors.lastname: Chen
authors.affiliation: Chemistry and Chemical Engineering, Southwest University, No. 2 Tiansheng Road, Beibei District, Chongqing 400715, PR China. Electronic address: hxpengjd@swu.edu.cn.
authors.forename: Jingdong
authors.initials: J
authors.lastname: Peng
authors.affiliation: Chemistry and Chemical Engineering, Southwest University, No. 2 Tiansheng Road, Beibei District, Chongqing 400715, PR China.
authors.forename: Shaopu
authors.initials: S
authors.lastname: Liu
authors.affiliation: Chemistry and Chemical Engineering, Southwest University, No. 2 Tiansheng Road, Beibei District, Chongqing 400715, PR China.
authors.forename: Huanjun
authors.initials: H
authors.lastname: Peng
authors.affiliation: Chemistry and Chemical Engineering, Southwest University, No. 2 Tiansheng Road, Beibei District, Chongqing 400715, PR China.
authors.forename: Ziyu
authors.initials: Z
authors.lastname: Pan
authors.affiliation: Chemistry and Chemical Engineering, Southwest University, No. 2 Tiansheng Road, Beibei District, Chongqing 400715, PR China.
authors.forename: Lingli
authors.initials: L
authors.lastname: Bu
authors.affiliation: Chemistry and Chemical Engineering, Southwest University, No. 2 Tiansheng Road, Beibei District, Chongqing 400715, PR China.
authors.forename: Huan
authors.initials: H
authors.lastname: Xiao
authors.affiliation: Chemistry and Chemical Engineering, Southwest University, No. 2 Tiansheng Road, Beibei District, Chongqing 400715, PR China.
authors.forename: Ruiwen
authors.initials: R
authors.lastname: Zhang
mesh_terms: D002614:Chelating Agents / Q000737:chemistry*; D003224:Congo Red / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D008968:Molecular Conformation; D018697:Nootropic Agents / Q000737:chemistry*; D009994:Osmolar Concentration; D010165:Palladium / Q000737:chemistry*; D010889:Piracetam / Q000737:chemistry; D011759:Pyrrolidines / Q000737:chemistry; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence
chemical_list: D002614:Chelating Agents; D018697:Nootropic Agents; D011759:Pyrrolidines; D003224:Congo Red; D010165:Palladium; C040619:oxiracetam; D010889:Piracetam
keywords: Congo red; Fluorescence; Nootropic; Palladium (II); Resonance Rayleigh scattering