Premium
Determination of L ‐Cystine by a New Sensitive Cucurbit[7]uril/palmatine Probe
Author(s) -
Yang Jiyuan,
Du Liming,
Wu Hao,
Chang Yinxia,
Li Changfeng
Publication year - 2011
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.201190235
Subject(s) - chemistry , cystine , palmatine , fluorescence , detection limit , aqueous solution , quenching (fluorescence) , analytical chemistry (journal) , chromatography , stereochemistry , organic chemistry , cysteine , alkaloid , enzyme , physics , quantum mechanics
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 Δ F and L ‐cystine concentration was obtained in the range of 6.0 to 1.5×10 3 ng·mL −1 , 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.