中文摘要：

利用荧光素标记的可识别赭曲霉素A的核酸适配体，以及荧光猝灭基团标记的互补核酸建立了一种检测赭曲霉素A的荧光分析法。标记有荧光素的核酸适配体（FDNA）未与赭曲霉素A结合时，可与标记有猝灭基团BHQ（BlackHoleQuencher）的互补寡聚核苷酸链（QDNA）杂交，使荧光基团与猝灭基团靠近，导致荧光猝灭；而当加入赭曲霉素A之后，FDNA与赭曲霉素A高亲和力高特异性结合，FDNA将不会与QDNA杂交，FDNA的荧光信号得到保持。根据FDNA与目标物结合前后荧光强度的变化，可实现对赭曲霉素A的定量检测。当FDNA浓度为36nmol／L，QDNA浓度为126nmol／I。，结合缓冲溶液为10mmol／LTris—HCl（含120mmol／LNaCl、20mmol／I。CaCl2、0．02％Tween20，PH-8．5），室温下反应15min后，可以获得最佳检测效果。对赭曲霉素A的线性检测范围是10～100nmol／L，检出限为10nmol／L，相对标准偏差为5．8％。该方法操作简单，选择性好。

英文摘要：

By using fluorescein labeled aptamer for ochratoxin A （OTA） and quencher labeled complementary oligonucleotides,a fluorometric method for OTA detection was developed. In the absence of OTA, the fluorescein-labeled aptamer（FDNA） bound to complementary ssDNA containing a quencher moiety of BHQ（Black Hole Quencher）（QDNA）, and the fluorescein and the quencher were close, resulting in fluorescence quenching. In the presence of OTA,FDNA bound to OTA with high affinity and specificity and was separated from QDNA, so that the fluorescence signal of FDNA was recoveried. According to the changes of the fluorescence intensity,OTA could be quantitatively detected. An optimal analytical performance could be achieved by applying FDNA at 36 nmol/L, QDNA at 126 nmol/L, binding buffer solution containing 10 mmol/L Tris-HCl（pH 8.5）, 120 mmol/L NaC1,20 mmol/L CaClz and 0.02% Tween 20,and incubation of solution at room temperature for 15 min. Under the optimal conditions,the linear concentration range for the OTA detection was from 10 nmol/L to 100 nmol/L with a detection limit of 10 nmol/L. The relative standard deviation was 5.8%. This method was easy to be operated with good selectivity.