[Reflections on construction of the experimental course system for environmental science in colleges and universities].

The training effects of experimental courses determine the practical abilities of undergraduate students. Therefore, it is essential to establish a comprehensive experimental course system that adapts to the undergraduate education of environmental science. Here, we introduce the "basic-specialized-comprehensive" experimental course system of Xiamen University, which is established following the principles of being systematic, comprehensive, and modular. To establish this course system, we first increased the investment of lab facilities and enhanced the management of student labs. Then, we improved the contexts of teaching and training according to the requirements of industry and society. Showing how this course system is developed stepwise and the training effects of this system, we hope to provide a reference for the experimental courses of environmental science in colleges and universities.

[Study on ratiometric determination of peroxynitrite and its scavenger based on synchronous fluorescence spectroscopy].

A ratiometric fluorimetry is proposed for the determination of peroxynitrite (ONOO-) and the evaluation of its scavenger based on synchronous fluorescence spectroscopy. L-tyrosine, an intrinsic fluorescent aminoacid, reacts with peroxynitrite and carbon dioxide, yielding a highly fluorescent dimer of tyrosine in pH 8.5 PBS buffer solution. By synchronous fluorescence scanning, both monomer and dimer emission bands of L-tyrosine appeared at 364 and 406 nm, respectively. The ratio of F406/ F364 is quantitatively related to the concentration of peroxynitrite, where F406 represents the intensity of synchronous emission band of dimer and F364 represents that of monomer. The method has been showing merit of being insensitive to the changes in experimental parameters and offers a higher sensitivity and a broader responding linear range of the analyte concentration, compared to fluorimetric method, giving a LOD of 1.84 X 10(-8) mol x L(-1) and a linear range of 1.60 X 10(-7) mol x L(-1)-6.00 X 10(-6) mol x L(-1) for ONOO-, respectively, with a deviation of 2.4% for 1.00 X 10(-6) mol x L(-1) ONOO- (n = 8). A IC50 of 0.065 microg x mL(-1) for mitoxantrone, an antioxidant and anticancer drug, was also obtained. This method has proved to be simple and speedy. It would be easily used in the determination of ONOO- and its scavenger.

Probing the hydroxyl radical-mediated reactivity of peroxynitrite by a spin-labeling fluorophore.

The decomposition of peroxynitrite at physiological pH yielded a hydroxyl radical, which reacted rapidly with dimethyl sulfoxide (DMSO) to produce a methyl radical (*CH3), which was then trapped by a spin-label fluorophore nitroxide-linked naphthalene (NTEMPO), a carbon-centered radical probe with a low fluorescence intensity, and transformed to a stable diamagnetic O-alkoxyamine, a high-fluorescence compound. The fluorescence increment was proportional to the concentration of the hydroxyl radical, and then to the concentration of peroxynitrite. NTEMPO therefore was demonstrated to be capable of detecting hydroxyl radicals generated from peroxynitrite, and the method was proved to be simple and sensitive. The hydroxyl radical-mediated reactivities of peroxynitrite to several amino acids, such as tyrosine, phenylalanine and histidine, were then evaluated by the spin-labeling fluorophore NTEMPO at pH 7.4 and, 37 degrees C. The obtained data were in good agreement with the reference values, respectively.