[The medium effects of fluorescence of eosin-5-isothiocyanate as a luminescent marker].

In this paper, the medium (pH, organic solvent and surfactant) effects on fluorescence of eosin-5-isothiocyanate (eosin-ITC) have been studied in detail. The results show that the pH and polarity of system studied are two great important influence factors on fluorescence of eosin-ITC. The fluorescence intensity of eosin-ITC in weak acidic medium is higher obviously than that of in weak basic medium, but it is sensitive to change of pH, be careful to use. The reaction between surfactant and eosin-ITC shows a good electric selectivity, and the effect of CTMAB on fluorescence of eosin-ITC can be classified as two stages: monomer quenching (below cmc) and micelle sensibilization (above cmc). In the presence of micelle of CTMAB, the fluorescence intensity of eosin-ITC in weak basic medium is even higher than that of in weak acidic medium. In the presence of high organic solvent content, the fluorescence intensity of eosin-ITC is also increased obviously. These properties are available for use.