Showing papers by "Yongnian Ni published in 2009"
TL;DR: The results suggest that at low concentrations, warfarin binds at the high-affinity sites (HAS), while low-Affinity binding sites (LAS) are occupied at higher concentrations.
112 citations
TL;DR: It was demonstrated with the use of principal component analysis (PCA), that multi-wavelength fingerprints provided a much improved representation of the differences in the samples, and appeared to be best suited for quality assurance purposes for these and similar types of sample.
77 citations
TL;DR: The proposed method was applied for the simultaneous determination of the five colorants in foodstuff samples, and the results were comparable with those from a reference HPLC method.
75 citations
TL;DR: In this paper, a method for simultaneous enzymatic kinetic determination of the pesticides, oxamyl, aldicarb and aminocarb in fruit, vegetables and water samples, was developed.
Abstract: A method for the simultaneous enzymatic kinetic determination of the pesticides, oxamyl, aldicarb and aminocarb in fruit, vegetables and water samples, has been researched and developed. It was based on enzymatic reaction kinetics and spectrophotometric measurements, and results were interpreted with the aid of chemometrics. The analytical method relies on the inhibitory effect of the pesticides on acetylcholinesterase (AChE), and the use of 5,5′-dithiobis (2-nitrobenzoic) acid (DTNB) as a chromogenic reagent for the thiocholine iodide (TChI) released from the acetylthiocholine iodide (ATChI) substrate. The complex rate equation for the formation of the chromogenic product, P, was solved under certain experimental conditions, and this enabled the absorbance (A p, at λ max = 412 nm) from the mixtures of the three pesticide inhibitors to be directly related to their concentrations. The detection limits of the enzymatic kinetic spectrophotometric procedures for the determination of the oxamyl, aldicarb and a...
12 citations
TL;DR: In this article, the competitive interaction of terazosin hydrochloride and prazosin hydchloride with BSA was studied by three-way excitation-emission fluorescence with the aid of parallel factor analysis.
Abstract: The binding interaction of the terazosin hydrochloride and prazosin hydrochloride with bovine serum albumin (BSA) was studied by spectrofluorimetry. Both of these two compounds quenched the fluorescence of BSA. The thermodynamic parameters (ΔH 0, ΔS 0 and ΔG 0) obtained from the fluorescence data measured at two different temperatures showed that the binding of terazosin hydrochloride to BSA involved hydrogen bonds and that of prazosin hydrochloride to BSA involved hydrophobic and electrostatic interactions. In this work, the competitive interaction of the terazosin hydrochloride and prazosin hydrochloride with BSA was studied by three-way excitation-emission fluorescence with the aid of parallel factor analysis (PARAFAC).
4 citations