基于荧光探针对食物中半胱氨酸的检测方法建立

为建立食品中半胱氨酸简便、灵敏的测定方法，利用荧光光度法建立了基于Rosamine荧光探针的半胱氨酸检测体系。该探针以Rosamine为信号报告单元、以苯乙炔基为反应位点，可通过迈克尔（Michael）加成反应和分子内环化反应实现对半胱氨酸选择性检测。结果表明，在磷酸缓冲液浓度为10 mmol/L，pH9.5，甲醇/水体积比为1:9，室温反应35 min条件下，探针选择性识别半胱氨酸，其相对荧光强度随半胱氨酸浓度增大而增强。半胱氨酸在18.0~70.0 μmol/L浓度范围内与该探针响应呈现较好的线性关系（R2=0.992），检出限为0.18 μmol/L （S/N=3）。将该方法用于水、牛奶、奶粉、白菜、苹果、梨及萝卜中检测半胱氨酸，加标回收率为96.4%~102.97%，相对标准偏差为0.1%~2%。该方法简便、灵敏度高、选择好，可用于实际样品中半胱氨酸的测定，具有较好应用前景。

Establishment of Cysteine Detection Method in Food Based on Fluorescent Probe

A novel,simple and sensitive fluorescenct method for determination of cysteine in water,milk,milk powder,cabbage,apple,pear and radish was established based on rosamine fluorescent probe.The probe was constructed by rosamine as the signal reporter and phenylalkynyl as the reaction site.Through Michael addition and intramolecular reaction,the probe could detect cysteine with high selectivity and sensitivity.Results indicated that under the optimized conditions of phosphoric acid buffer concentration of 10 mmol/L,pH9.5,methanol/water volume ratio of 1:9 and room temperature reaction for 35 min,the probe selectively recognized cysteine,and its relative fluorescence intensity increased with the increasing of cysteine concentration.Furthermore,the fluorescence signal of the probe had a good linear relationship with cysteine in the concentration range from 18.0 to 70.0μmol/L(R²=0.992)with detection limit of 0.18μmol/L.Furthermore,the method was used to determinate cysteine in water,milk,milk powder,cabbage,apple,pear and radish with good recoveries(96.4%~102.97%)and RSD(0.1%~2%).This suggested that the approach would have high selectivity,sensitivity and the feasibility of cysteine detection in practical sample,as well as a good application prospect.