Entity

Time filter

Source Type


Zong W.,Shandong University | Zong W.,Shandong Normal University | Zong W.,America Cooperative Research Center for Environment and Health | Xu Q.,Shandong University | And 3 more authors.
Luminescence | Year: 2012

This article concerns a new and precise strategy for the determination of Cu 2+ based on a color reaction and outer filter effects (OFEs). Cu 2+ can react with sodium diethyldithiocarbamate trihydrate (DDTC) to form a DDTC-Cu 2+ complex with a significant absorption at 447 nm. Being positively correlated with Cu 2+, the absorption could be treated as the basis for the determination of Cu 2+. When cuvettes containing the complex were fixed in the light path of a fluorescence spectrophotometer, the excitation/emitted light were absorbed by the OFEs, similar to absorption mechanisms of inner filter effects. Under suitable conditions, OFEs from the complex could quantitatively reduce the fluorescence intensities of quinine sulfate and acridine yellow by absorbing the excitation or emission light. Compared with traditional absorption spectroscopy (with a detection limit at 0.9 μmol/L), indirect OEF techniques showed increased sensitivities by about 1 order of magnitude. The strategy could be extended to many different systems where components absorb the excitation wavelength and/or emission wavelength of fluorescers. Copyright © 2011 John Wiley & Sons, Ltd. Source


Yuan D.,Shandong University | Yuan D.,Shandong Normal University | Yuan D.,America Cooperative Research Center for Environment and Health | Shen Z.,Shandong Supervision and Inspection Institute for Product Quality | And 4 more authors.
Journal of Luminescence | Year: 2011

The interaction of La3 to bovine serum albumin (BSA) has been investigated mainly by fluorescence spectra, UVvis absorption spectra, and circular dichroism (CD) under simulative physiological conditions. Fluorescence data revealed that the quenching mechanism of BSA by La3 was a static quenching process and the binding constant is 1.75×104 L mol-1 and the number of binding sites is 1 at 289 K. The thermodynamic parameters (ΔH=-20.055 kJ mol-1, ΔG=-23.474 kJ mol-1, and ΔS=11.831 J mol-1 K-1) indicate that electrostatic effect between the protein and the La3 is the main binding force. In addition, UVvis, CD, and synchronous fluorescence results showed that the addition of La3 changed the conformation of BSA. © 2011 Elsevier B.V. All rights reserved. Source


Jun C.,Shandong University | Jun C.,America Cooperative Research Center for Environment and Health | Xue Y.,Shandong Jianzhu University | Liu R.,Shandong University | And 3 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

The toxic interaction of methanol, ethanol and propanol with bovine hemoglobin (BHb) at protein molecular level was studied by resonance light scattering (RLS), fluorescence, ultraviolet-visible absorption (UV-vis) and circular dichroism (CD) techniques. The experimental results showed that the three alcohols all had toxic effects on BHb and the effects increased along with the increasing alcohol dose. The results of RLS and fluorescence spectroscopy showed that alcohols can denature BHb. They changed the microenvironment of amino acid residues and led to molecular aggregation. The decreasing order of the influence is propanol, ethanol and methanol. The results of UV-vis and CD spectra revealed that alcohols led to conformational changes of BHb, including the loosening of the skeleton structure and the decreasing of α-helix in the second structure. The changes generated by propanol were much larger than those by methanol and ethanol. © 2011 Elsevier B.V. All rights reserved. Source


Qin P.,Shandong University | Qin P.,America Cooperative Research Center for Environment and Health | Liu R.,Shandong University | Liu R.,America Cooperative Research Center for Environment and Health | And 2 more authors.
Journal of Agricultural and Food Chemistry | Year: 2011

Perfluorodecanoic acid (PFDA), a representative of the perfluoroalkyl acids, poses a great threat to humans and animals via food and other potential sources. In this work, we determined the effects of PFDA binding to two hemoproteins, bovine hemoglobin (BHb) and myoglobin (Mb). Using fluorescence spectroscopy, we found that PFDA greatly enhanced the fluorescence intensity of both hemoproteins, while perfluorooctanoic acid (PFOA) and perfluoropentanoic acid (PFPA) have minimal effects on the fluorescence. UV-vis absorption (UV) spectroscopy showed that PFDA induced the unfolding of the hemoproteins accompanied by exposure of the heme pocket and facilitating the formation of hemichrome. Additionally, as shown by the circular dichroism (CD) data, PFDA altered the secondary structure of both BHb and Mb. This work elucidates the interaction mechanism of PFDA with two hemoproteins. © 2011 American Chemical Society. Source


Pan X.,Shandong University | Pan X.,America Cooperative Research Center for Environment and Health | Qin P.,Shandong University | Qin P.,America Cooperative Research Center for Environment and Health | And 4 more authors.
Journal of Agricultural and Food Chemistry | Year: 2011

Tartrazine is an artificial azo dye commonly used in food products. The present study evaluated the interaction of tartrazine with two serum albumins (SAs), human serum albumin (HSA) and bovine serum albumin (BSA), under physiological conditions by means of fluorescence, three-dimensional fluorescence, UV-vis absorption, and circular dichroism (CD) techniques. The fluorescence data showed that tartrazine could bind to the two SAs to form a complex. The binding process was a spontaneous molecular interaction procedure, in which van der Waals and hydrogen bond interactions played a major role. Additionally, as shown by the UV-vis absorption, three-dimensional fluorescence, and CD results, tartrazine could lead to conformational and some microenvironmental changes of both SAs, which may affect the physiological functions of SAs. The work provides important insight into the mechanism of toxicity of tartrazine in vivo. © 2011 American Chemical Society. Source

Discover hidden collaborations