中文摘要：

利用G四聚体可以熄灭荧光的特性以及T—Hg^2＋-T的特殊结构，发展了一种简便的“Tumon”型碘离子检测新方法．设计了一条5′端标有荧光基团的富T序列，3′端采用能形成G四聚体的富G序列代替传统的熄灭基团．加入汞离子后，富T序列形成T—H^2＋-T机构发生折叠，G四聚体靠近荧光基团，发生光诱导电子转移，使荧光被熄灭．若加入碘离子，碘离子会与汞离子形成较稳定的配合物，汞离子从DNA上被竞争下来，探针的荧光得以恢复，且荧光强度与50～500nmol／L的碘离子呈良好线性关系，检出限为30nmol／L．本方法选择性好，10倍于碘离子浓度的其它常见阴离子干扰较小．检测自来水样中碘离子的回收率为92％～109％，相对标准偏差RSD〈4％（n=4）．

英文摘要：

A simple and ＂Turn on＂ type iodide anion assay method was developed, based on the inherent quenching ability of G-quadruplex and fidelity of the ＂thymine-Hg^2＋-thymine＂ binding motif. A T-rich sequence was labeled with 6-carboxyfluorescein （FAM） at its 5′-end, nearby the 3′-end was a G-rich sequence which could form G-quadruplex structure instead of traditional quenchers. Upon addition of Hg^2＋ , T-rich sequence folded into a hairpin structure which led the G-quadruplex near to the FAM, and the FAM was quenched by the G-quadruplex owning to photoinduced electron transfer between the dye and the G-quadruplex. After the addition of iodide, the fluorescence of FAM recovered considering that iodide could bind with Hg^2＋. The novel method for the determination of iodide was developed in linear range of 50-500 nmol/L, with the detection limit（3σ） of 30 nmol/L. This proposed method was highly selective and other anions have no interfering effects on the determination, which was successfully applied for analysis of real samples with the recovery from 92%-109% and the RSD〈4% （n=4）.