School of Agriculture and Biology, Key Laboratory of Urban Agriculture, Ministry of Agriculture, Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China.
Meteorological Bureau of Liupanshui, Liupanshui, 553000, People's Republic of China.
Mikrochim Acta. 2019 Sep 5;186(10):668. doi: 10.1007/s00604-019-3788-8.
A fluorometric method is described for the determination of ofloxacin (OFL). It is based on the use of the fluorescent intercalator SYBR Green I (SG-I). The OFL-aptamer has G-quadruplex structures and can be recognized by SG-I. It results in strong fluorescence of SG-I. If OFL is present, OFL will bind to its aptamer to form stable complexes. This induces the despiralization of partial dsDNA regions, leads to changes in the structure of the aptamer. Thus, SG-I is released from the OFL-aptamer into solution. Hence, the fluorescence of SG-I drops. Fluorescence decreases linearly in the 1.1 to 200 nM OFL concentration range, and the limit of detection is 0.34 nM. The method shows good selectivity to much interference including analogues, hormones, pesticides. It is also effortless and fast with the times of measurement of <40 min. In addition, good recoveries of 91.3-119.0% were found for tap water, river water and artificial urine spiked with OFL with relative standard deviation (RSD) of ≤11.6%. Graphical abstract A sensitive fluorometric method is developed for ofloxacin (OFL) detection in aqueous samples based on the fluorescence intensity change of SYBR Green I (SG-I) with or without OFL.
一种荧光法测定氧氟沙星（OFL）的方法。它基于使用荧光嵌入剂 SYBR Green I（SG-I）。OFL-适体具有 G-四链体结构，可以被 SG-I 识别。这导致 SG-I 的强荧光。如果存在 OFL，OFL 将与其适体结合形成稳定的复合物。这诱导部分 dsDNA 区域的去螺旋化，导致适体结构的变化。因此，SG-I 从 OFL-适体中释放到溶液中。因此，SG-I 的荧光减弱。荧光在 1.1 到 200 nM OFL 浓度范围内呈线性下降，检测限为 0.34 nM。该方法对包括类似物、激素、农药在内的多种干扰具有良好的选择性。此外，该方法还具有测量时间短（<40 分钟）、操作简便快速的优点。对于自来水、河水和人工尿液中添加的 OFL，回收率为 91.3-119.0%，相对标准偏差（RSD）≤11.6%。
