摘要：

Novel fluorescent probes and methods for the determination of lactate and hydrogen peroxide (HP) are presented.The first part describes the design and preparation of two fluorescent probes for HP. The naphthalimide fluorophores 5 (which is referred to as HP Green) and 8 have either a p-anisidine (HP Green) or N,N-dimethyl-p-phenylene diamine (8) group attached as a redox active moiety. Both probes display absorption around 450 nm and emission at 534 nm. HP Green is more suitable for experiments under physiological conditions. Photoinduced electron transfer from the redox moiety to the fluorophore is suppressed after oxidation with HP. This effect is further increased in presence of horseradish peroxidase (HRP), and fluorescence rises up to 11-fold. The dynamic range of HP Green for HP is from 100 nM to 5 M with a limit of detection (LOD) of 64 nM. L-Lactate detection affords lactate oxidase in combination with HP Green and HRP to yield a fast enzymatic assay (6 min). The dynamic range is from 0.5 to 10 M of L-lactate with a LOD of 162 nM, which is 6-fold lower than methods that apply Amplex Red (LOD 1 M). Furthermore, a D-glucose assay with glucose oxidase was established, which has a dynamic range from 2 to 30 M. The LOD of 0.64 M is 3-fold lower than that of the respective Amplex Red system (2 M). HP Green also was applied as an in-vitro probe for imaging of HP in NRK cells. Finally, the feasibility of a reusable chemosensor for HP is shown.The second part aims at the development of probes that directly bind lactate upon covalent interactions. Phenylboronic acids are connected to either a hemicyanine fluorophore (10) or ruthenium(II)-complexes (12a/b). Upon excitation at 460 nm, all fluorophores emit red light around 610 nm and differ in their response to both lactate enantiomers. The experiments hint at boronic acids being suitable to the detection of lactate and to differentiate between the two enantiomers. However the presence of saccharides must be avoided.In the last part, the blue cyanine dyes 13 and 14 were shown to change their colour to purple in acidic aqueous solutions. Changes occur faster for derivative 14, hence, the purple decomposition product of 14 was isolated with preparative HPLC and its molecular weight was determined to be 754.3 g/mol. The dye displays absorption at 534 nm and two emission maxima at 547 and 588 nm. Finally, a colorimetric sensor for acidic gases was developed exploiting the chameleon properties of 14 in presence of gaseous hydrochloric acid. The sensor changes its colour from blue to purple upon exposition to low amounts of gaseous HCl (0.1 bar), and high partial pressures of HCl can accelerate the response to less than 30 min.

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