Fluorescence Quenching Of Ofloxacin Or Phenanthrene By Fullerene

The special molecular structure makes fullerenes having many very attractive ph ysical and chemical properties, which promoted their wide application in the field of commercial production and engineering materials.Fullerene is not soluble in water, but it usually needs to be dispersed before application, namely preparing stable fuller enes colloidal suspension (nC6o). In the process of extensive use of fullerenes, it will b e released into the environment, and affect people’s health and life. Also, in the enviro nment, besides fullerenes, there are millions of pollutants, which contains ofloxacin a nd phenanthrene these two types of pollutants. They are likely to interact with a series of fullerenes, thus have a greater harm. So, a deep understanding of the environment of fullerene behavior, and explore the interaction of fullerenes and other poisonous an d harmful substances in the environment, will be better for us to evaluate fullerenes en vironmental risk. In this paper, the method of solvent exchange combined with ultraso nic was first to used for preparing of fullerenes colloidal suspension and then by fluor escence quenching method investigates the interactions of fullerenes and ofloxacin, p henanthrene to discuss its possible mechanism. The major conclusions of the study we re as follows:(1) The fullerenes colloidal suspension (nC60)was prepared with organic solvent exchange combined with ultrasonic method, then by changing the concentration of the fullerene (0.1 mg/L-10 mg/L) and the temperature (T= 25 ℃-T= 45 ℃), the aver age particle size and Zeta potential values of fullerenes was nearly unchanged in the r ange of allowable error. This fully shows that experiment of the preparation of fullere nes colloidal suspension is stable.(2) Fullerene colloidal suspension is sensitive to pH and ionic strength. Regardless of the system decrease or increase of pH value, the average particle size of fullerenes will increase. When educed the pH, it would to form larger particle size particles due to electrostatic interactions. pH value was increasesd, the introduction of a certain intensity of cation, it would combine with negatively charged fullerenes and bacame large particle size.(3) The Zeta potential of fullerenes would reduce gradually along with the increa se of pH value, and H+ and OH- was the major reasons.For the former,the protonation activity of fullerene surface with a negative charge would reduce the Zeta potential. A nd OH- concentration increasing, marked the negative Zeta potential of fullerenes coll oidal suspension system was increased.(4) Some concentration of ofloxacin (OFL) and phenanthrene (PHE) had a strong fluorescence response in a specific wavelength range. Fullerene (nC60) was a quenche r, which could cause fluorescence intensity reduced of OFL and PHE by fluorescence quenching. Whether the OFL or PHE, at room temperature (T= 25 ℃), the Figure w as not linear made by the Stern-Volmer equation, but curved upward curve, which sho wed the fluorescence between nC6o and OFL, PHE quenching phenomenon was gener ated by the common interactions of dynamic and static quenching quenching. But the change in temperature of the system, namely when the temperature rised, FO/F value is also decreased, indicating that between nC60 and OFL, PHE mainly static quenchin g based.There were too many possible mechanisms in the fluorescence quenching of OFL, PHE by nC60, including:the hydrophobic effect, the hydrogen bond, π-π electro n donor-acceptor (EDA) interaction etc.(5) The combination curve of OFL-nC60, PHE-nC60 showed that with the incre ase of concentration nC60, the combination quantity of OFL and PHE were decreased. As the OFL or the addition of PHE, nC6o average particle size increased and made the hydrophobicity of specific surface area to reduce, leading to combined nC60 OFL or a reduction in the Whether was a possible reason was that with the increase of OFL or P HE, fullerenes colloidal suspension stability was Damaged, namely fullerenes in the c oagulation happened do not combine with OFL or PHE in the system, which caused O FL or PHE quantity decreased.(6) With the increase of temperature (T= 25℃-T= 45℃), the combination of OFL-nC60, PHE-nC60 were decreased. The fluorescence quenching type of OFL, PHE by nC60 was given priority to with static quenching, which was exothermic proce ss of energy reduction. Therefore, when the temperature rised, the reaction would lead to generate complex reverse Less, that is, The combination were decreased.