Application Of Fluorescence Method In Determination Of Nicotine And Lomefloxacin

The fluorescence analysis is characterized by simple instrument, rapid method and high sensitivity. The method has 2-3 orders of magnitude higher sensitivity than UV analysis. Therefore, it is widely used in analysis field. This paper has carried on the study by fluorescence analysis determination of nicotine in cigarette and lomefloxacin in drugs. This paper consists of four chapters:Chapter one:We summarized methods for extraction of Nicotine from Tobacco such as the diyestion-extraction, SFE, the liquid film extract, iron exchange and reviewed gravimetric method, titration method, photometer method, the electric potential analytical method, chromatogram method and CE analytical method of nicotine with 33 relevant literatures in recent years.Chapter two:This experiment purposed a new method for determination of nicotine in cigarettes using fluorescence with fluorescein. It was shown that in the water solution consisting of nicotine and fluorescein at pH=7.3, the fluorescent intensity of fluorescein atλex/λem=450/510 nm increased as a result of electrostatic attraction and association reaction. Based on this phenomenon, a new method for determination of nicotine was established. The concentration of nicotine and fluorescent intensity of fluorescein was linear within the range of 0.2～8.0 mg/L. The detection limit was 0.12 mg/L. This method of determination of nicotine could be implemented in various brands of cigarettes. Among six parallel determinations, the recovery was 91.1%～108.8% and the RSD was 1.8%～4.8%. Results were satisfactory.Chapter three:Nicotine in cigarettes was determined by the method of fluorescein-safran-ine T fluorescence energy transfer. The experiment showed that:efficient energy transfer happened in the mixture of fluorescein(FL) and safranine T(ST), nicotine could damage and inhibit the energy transfer reaction. As a result, the fluorescence of FL was increased. We established the new method for determination of nicotine by fluorescence. The concentration of Nicotine in 0.2～7.0 mg/L, the relation of nicotine and fluorescent intensity was linear; the detection limit was 0.18 mg/L. It can be used in the determination of nicotine in various brands of cigarettes. The recovery was 99.0%～105.0% among 6 determinations and the RSD was 1.1%～4.8%. Results were satisfactory.Chapter four:A method has been established for quantitative determination of lomefloxacin hydrochloride by fluorescence quenching of Fe (Ⅲ)-lomefloxacin-eosin. In the acid medium, the fluorescence of lomefloxacin-eosin could be quenched by the Fe(Ⅲ), which indicated the formation of a Fe(Ⅲ)-lomefloxacin-eos-in complex. Based on the linear relationship between fluorescence intensity and lomefloxacin concentration, we established a new method for the determination of lomefloxacin in the range of 77.6～970μg/L withλex/λem=348/540 nm. The detection limit of this method was 11.4μg/L. The recoveries were 85:75%～111.25% and the RSD was 1.37%～2.1%(n=6). The method could be applied in the determination of lomefloxacin in tablets produced by different companies with a satisfactory result.