| As a typical heavy metal, Mercury has been known as a toxic metal since antiquity.Once introduced into the marine environment, bacteria convert inorganic mercury into methylmercury, which enters the food chain and accumulates in higher organisms, especially in large edible fish. Methylmercury is neurotoxic and has been implicated as a cause of prenatal brain damage, various cognitive and motion disorders, and Minamata disease.To monitor and prevent mercury pollution, efforts are being made worldwide to develop new mercury detecting strategies for monitoring mercuric ion from the environment and biological samples,now several techniques are available.As a link of material science and analysis chemistry, the study in fluorescent sensor and novel sensor material has received a growing attention with the rapid development of cross subject. They provide accurate, on-line, and low-cost detection of toxic heavy metal ions with high selectivity and sensitivity and have been used in a variety of fields such as environmental chemistry, analytic chemistry, and bio-medicinal science.The fluorescence intensities of common probes (both fluorescence quenching and fluorescence enhancement) are influenced by experimental factors such as photobleaching ,excitation intensity, the micro-environment around the dye, and the concentration of the dye. The ratiometric probes can normalize the variation of these effects and provide more robust and precise measurement results.Aminonaphthalimide derivatives are attractive fluoroionophore owing to their good photophysical properties with strong fluorescence, large Stokes shifts and relatively steady emission wavelengths. We design and synthesis a novel chemosensor(4-aminonaphthalimide - 8-hydroxyquinoline) based on Hg2+-induced fluorescence resonance energy transfer (FRET) and photoinduced electron transfer (PET). Hg2+ can be detected and quantitated by measuring the fluorescent intensity change. Addition of Hg2+ to a ethanol solution of fluoroionophore gave a significant enhanced fluorescence at about 520 nm of 4-Aminonaphthalimide and quenched fluorescence at about 360 nm of quinoline. It exhibits a linear response toward Hg2+ in the concentration range 2.0×10-7-6.6×10-5 mol L-1 with a high selectivity.To minimize the effects of the background fluorescence, We successfully design and synthesis another fluoroionophore(4-aminonaphthalimide - porphyrin). Compared with former fluoroionophore of chapter one, this chemosensor have relatively longer excitation(416nm) and emission(525nm of aminonaphthalimide and 650 of porphyrin ) wavelengths. It also exhibits a wider linear response toward Hg2+ in the concentration range 7.8×10-7 to 1.2×10-4 mol L-1, and lower detection limit about 8.0×10-8 mol L-1.The fluorescence can't be influenced by pH at a working range from 4.0 to 8.0.We also dabbled ion-selective electrodes and successfully designed a new compound -amide-linked manganese diporphyrin xanthene(Mn2Cl2ADPX)- as electro active materials of electrode to detect the thiocyanate. The electrode exhibited linear response within the concentration range of 2.4×10-6 to 1.0×10-1 mol L-1 SCN-, with a working pH range from 3.0 to 8.0 and a fast response time of less than 60s. The electrode exhibits anti-Hofmeister selectivity toward SCN- with respect to common co-existing anions. The electrode was applied to the determination of SCN- in body urine with satisfactory results.
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