Preparation Of Novel Fluorescent Molecular Probes And Their Applications For Ion Recognition

In recent years, the recognition and detection of significant species in biology and environment has owned more and more attention as an important goal in the field of chemical sensors. Some analytical techniques, such as high-performance liquid chromatography, mass spectrometry, electrochemical sensing, atomic absorption spectroscopy and inductively coupled plasma atomic emission spectrometry have been employed for analyte sensing. But those methods are time-consuming and involve the use of sophisticated equipment, so fluorescence method capable of advantages of non-destructive and high sensitivity with simple instruments has emerged. To date, fluorescent sensors have been widely investigated for the selective detection of trace analytes. In this paper, we have applied novel organic fluorescence probes to detect copper (II) ion and fluoride ion respectively. These fast and high sensitive fluorescent sensors can be further used for biological/chemical and environmental systems.Chapter one is mainly about the fundamental principles of fluorescence, types of fluorescent materials, and the detection methods of analytes, such as reactive oxygen species, cations and anions. We have introduced some organic dyes, nanometer fluorescent material and biological fluorescent molecules in types of fluorescent materials. It is mainly introduced the fluorescent analytical methods of hypochlorous acid and nitrogen oxides in reactive oxygen species part, zinc and iron ions in cations part, cyanide and fluoride ion in anions part, respectively.In chapter two, we have prepared and obtained a novel dansyl-based green fluorescent probe with high photostability, pH insensitivity properties, and specific response to copper (II) ion. It shows high selectivity and sensitivity towards Cu2+ion and other metal ions have no effect on the fluorescence of the probe. The detection limit of the probe is2ppb, which is much lower than the recommended standard value for Cu2+in drinking water. The experiment has proved that copper (II) ion quenched the fluorescence of the probe by charge transfer. Spike recovery test also confirms its practical application in tap water samples. Due to its good biocompatibility and high photostability, the probe can be applied to biological and chemical systems. In chapter three, we have synthesized a novel "turn-on" organic molecular probe for fluoride ion based on the high reactivity of the silyl group toward fluoride ion. The probe reported here is photostable and simple to obtain. The nucleophilic substitution reaction between the Si and F triggers the cleavage of the Si-O bond, releases a strong fluorescent product and shows a turn-on response. The probe is specifically responsive and highly sensitive for the fluoride ion over other anions and cations. The detection limit was measured to be low as66.5ppb. This probe can be further employed in many aspects for the detection of fluoride ion.