酪蛋白对双羧基1,8-萘酰亚胺荧光探针聚集诱导发光效应的光谱研究及分析应用  

Study on Aggregation Induced Emission of Casein for 1,8-Naphthalimide Bearing Two Acetic Carboxylic Groups by Spectroscopic Method and Analytical Application

作　　者：刘振[1] 孙洋[1] 

机构地区：[1]西安文理学院化学与化学工程学院,西安710065

出　　处：《分析化学》2014年第1期41-46,共6页Chinese Journal of Analytical Chemistry

基　　金：陕西教育厅项目(No.2013JK0687);西安文理专项(No.CX12189WL04)资助

摘　　要：建立高效快速、操作简便、价格低廉的乳品真蛋白检测方法具有重要意义。本实验合成了具有双羧基官能团的水溶性1，8-萘酰亚胺荧光探针2，探针2对酪蛋白具有特异性发光效应，其机理是双羧基为前导嵌入基团插入酪蛋白胶团子域的疏水腔中，与色氨酸、酪氨酸等氨基酸残基以氢键及疏水作用相结合后使酪蛋白胶团结构收缩，萘酰亚胺荧光基元吸附于酪蛋白胶团表面呈现聚集诱导发光效应（Aggregationinducedemission，AIE）。以300nm为激发波长，一定范围内探针2在480nm附近处发光强度与酪蛋白浓度成正比，在pH5．5条件下建立了酪蛋白AIE定量分析方法；线性范围为0．1—9．5mg／L，检出限（3σ）为2．9mg／L，对不同浓度酪蛋白平行测定9次，相对标准偏差〈3％；三聚氰胺、铵肥、尿素、乳清蛋白、血清蛋白、I型胶原蛋白及粗卵清蛋白等对于测定结果无显著影响（±5％），用于奶粉中总酪蛋白含量的测定结果与双缩脲法相一致。A water-soluble 1,8-naphthalimide-based fluorescent probe 2, bearing two acetic carboxylic groups, exhibited specificity emission enhancement for casein. The mechanism is the acetic carboxylic groups of 2 docks into the hydrophobic sub-domains of casein and binds with the Trp and Tyr residues through hydrophobic interaction and hydrogen effect. The un-bound Trp and Tyr residues are buried in hydrophobic cave, which makes casein be more compact. The chromophore of naphthalimide adsorbs on the surface of casein micelle, and the aggregation induced emission enhancement （AlE） occurs. When the excitation wavelength is set at 300 nm, the fluorescence intensity around 480 nm of probe 2 is proportional to the concentration of casein, based on which, an AIE quantitative assay of casein is presented at pH 5.5. The hnear range was 0.1-9.5 mg/L and the detection limit was 2.9 μg/L. Relative standard deviation was less than 3% with different concentration of casein parallel determination for nine times. The melamine, urea, whey, serum album, collagen I and crude ovalbumin did not interfere or only interfered slightly under the permission of ± 5.0% relative error. The results of detecting casein in milk powder by this method were in good agreement with those of Biuret method.

关 键 词：1 8-萘酰亚胺 双羧基 酪蛋白 聚集诱导发光 

分 类 号：O657.3[理学—分析化学]