四磺基铝酞菁-十四烷基二甲基乙基氯化铵离子缔合物红色荧光探针用于硫酸软骨素的测定

Sensitive Determination of Chondroitin Sulfate by Fluorescence Recovery of an Anionic Aluminum Phthalocyanine-Cationic Surfactant Ion-Association Complex Used as a Fluorescent Probe Emitting at Red Region

硫酸软骨素的测定在生物医学领域有重要价值,但常规检测法在灵敏度、选择性或简易性方面尚存在不足。本文基于带正电基团的阳离子表面活性剂对具有红区发射特性的强荧光化合物—荷负电的四磺基铝酞菁具有高效荧光猝灭作用,而在生物多糖硫酸软骨素存在下,上述荧光猝灭体系荧光显著恢复的现象,提出酞菁-表面活性剂离子缔合物荧光恢复高灵敏测定硫酸软骨素的新方法,并用于实际样品分析。研究表明,中性介质中,红区荧光探针四磺基铝酞菁（Tetrasulfonated aluminium phthalocyanine,AlS4Pc）与阳离子表面活性剂十四烷基二甲基苄基氯化铵（Tetradecyldimethylbenzylammonium chloride,TDBAC）发生强烈的缔合作用,导致AlS4Pc的荧光几乎完全猝灭,从而获得暗背景的荧光体系。在加入带有阴离子基团（磺酸基）的生物多糖硫酸软骨素（Chondroitin sulfate,CS）后,由于竞争结合作用,AlS4Pc被释放而使体系的荧光大幅度恢复,且恢复程度与CS呈线性正相关。优化了反应条件,考察了共存物质的影响,结果表明本法具有较好的选择性。在最佳条件下,线性范围为0.20～10.0μg·mL^-1,检测限为0.070μg·mL^-1,工作曲线方程y=1.04x＋2.09,r=0.999 5。该法操作简便,灵敏度、稳定性与准确性好,实际样品的分析结果令人满意。酞菁荧光化合物在分析科学中的应用尚不多见,本文工作进一步开拓了酞菁红区荧光探针的新应用。

Determination of chondroitin sulfate in the biomedical field has an important value.The conventional methods for the assay of chondroitin sulfate are still unsatisfactory in sensitivity,selectivity or simplicity.This work aimed at developing a novel method for sensitive and selective determination of chondroitin sulfate by fluorimetry.We found that some kinds of cationic surfactants have the ability to quench the fluorescence of tetrasulfonated aluminum phthalocyanine（AlS4Pc）,a strongly fluorescent compound which emits at red region,with high efficiency.But,the fluorescence of the above-mentioned fluorescence quenching system recovered significantly when chondroitin sulfate（CS）exits.Tetradecyl dimethyl benzyl ammonium chloride（TDBAC）which was screened from all of the candidates of cationic surfactants was chosen as the quencher because it shows the most efficient quenching effect.It was found that the fluorescence of AlS4 Pc was extremely quenched by TDBAC because of the formation of association complex between AlS4 Pc and TDBAC.Fluorescence of the association complex recovered dramatically after the addition of chondroitin sulfate（CS）due to the ability of chondroitin sulfate to shift the association equilibrium of the association,leading to the release of AlS4 Pc,thus resulting in an increase in the fluorescence of the reaction system.Based on this phenomenon,a novel method with simplicity,accuracy and sensitivity was developed for quantitative determination of CS.Factors including the reaction time,influencing factors and the effect of coexisting substances were investigated and discussed.Under optimum conditions the linear range of the calibration curve was 0.20～10.0μg·mL^-1.The detection limit for CS was 0.070μg·mL^-1.The method has been applied to the analysis of practical samples with satisfied results.This work expands the applications of AlS4 Pc in biomedical area.