Determination of L-Cystine by a New Sensitive Cucurbit[7]uril/palmatine Probe  

作　　者：Yang, Jiyuan Du, Liming Wu, Hao Chang, Yinxia Li, Changfeng 

机构地区：[1]Analytical and Testing Center, Shanxi Normal University, Linfen, Shanxi 041004, China

出　　处：《Chinese Journal of Chemistry》2011年第6期1268-1272,共5页中国化学（英文版）

摘　　要：In the presence of cucurbit[7]uril （CB[7]）, the CB[7] could react with palmatine, which served as a sensitive fluorescence probe, to form host-guest stable complexes and the fluorescence intensity of the complexes was greatly enhanced. The fluorescence intensity decreased linearly with an increasing number of L-cystine in the inclusion system. The experimental results show that there exists a competition between L-cystine and palmatine for the CB[7] hydrophobic cavity and L-cystine occupies the space of CB[7] cavity, leading palmatine molecules to be forced to reside in the aqueous environment. Based on the fluorescence quenching of the CB[7]/palmatine complexes resulting from complex formation between CB[7] and L-cystine, a spectrofluorimetric method for the determination of L-cystine in aqueous solution in the presence of CB[7] was developed. The linear relationship between the corresponding values of the fluorescence quenching AF and L-cystine concentration was obtained in the range of 6.0 to 1.5 × 10^3 ngomL l, with a correlation coefficient （r） of 0.9996. The detection limit was 2.0 ng·mL -1. The application of the present method to the determination of L-cystine in tablets gave satisfactory results. This paper also discussed the mechanism of the fluorescence indicator probe.In the presence of cucurbit[7]uril （CB[7]）, the CB[7] could react with palmatine, which served as a sensitive fluorescence probe, to form host-guest stable complexes and the fluorescence intensity of the complexes was greatly enhanced. The fluorescence intensity decreased linearly with an increasing number of L-cystine in the inclusion system. The experimental results show that there exists a competition between L-cystine and palmatine for the CB[7] hydrophobic cavity and L-cystine occupies the space of CB[7] cavity, leading palmatine molecules to be forced to reside in the aqueous environment. Based on the fluorescence quenching of the CB[7]/palmatine complexes resulting from complex formation between CB[7] and L-cystine, a spectrofluorimetric method for the determination of L-cystine in aqueous solution in the presence of CB[7] was developed. The linear relationship between the corresponding values of the fluorescence quenching AF and L-cystine concentration was obtained in the range of 6.0 to 1.5 × 10^3 ngomL l, with a correlation coefficient （r） of 0.9996. The detection limit was 2.0 ng·mL -1. The application of the present method to the determination of L-cystine in tablets gave satisfactory results. This paper also discussed the mechanism of the fluorescence indicator probe.

关 键 词：fluorescence spectroscopy host-guest systems trace analysis L-CYSTINE 

分 类 号：O657.3[理学—分析化学] S153.62[理学—化学]