基于适配体的纳米金光学探针可视化法快速测定中药材中的啶虫脒

Rapid Determination of Acetamiprid in Chinese Herbal Medicine by Visualization Method Based on Aptamer with Gold Nanoparticles as Optical Probe

以农药啶虫脒适配体作为识别元件,以纳米金作为颜色指示剂,建立了一种基于啶虫脒适配体的纳米金光学探针特异测定中药材中啶虫脒含量的方法。用甲醇超声提取样品,离心后,上清液用无水MgSO_(4)和N-丙基乙二胺净化。纳米金溶液和啶虫脒适配体溶液在室温下反应15min后,加入样品溶液,继续反应20min,最后加入200mmol·L^(-1) NaCl溶液,静置5min。在高盐环境中,啶虫脒与适配体发生特异性结合,纳米金表面会因为失去适配体保护而发生聚集,体系颜色由红色变为蓝色。采用多功能酶标仪测量上述体系在520,650nm处的吸光度。结果显示:啶虫脒的质量浓度在20~200μg·L^(-1)内与650nm处和520nm处吸光度的比值呈线性关系,检出限为1.13μg·L^(-1)。对空白中药材进行3个浓度水平的加标回收试验,所得回收率为91.1%~105%,测定值的相对标准偏差(n=5)为1.1%~4.8%。方法用于多种中药材中啶虫脒的测定,在2种中药材中检出了啶虫脒,检出质量分数为329.10,125.22μg·kg^(-1)。

Using the pesticide acetamiprid aptamer as recognition element and gold nanoparticles as color indicator,a method of gold nanoparticles as optical probe based on the acetamiprid aptamer was established to specifically determine the content of acetamiprid in Chinese herbal medicines.The target compound in the sample was ultrasonically extracted with methanol.After centrifugation,the supernatant was purified with anhydrous MgSO_(4) and N-propyl ethylenediamine.After the gold nanoparticles solution together with the acetamiprid aptamer were reacted at room temperature for 15 min,the sample solution was taken and added to react with the above solution for 20 min.200 mmol·L^(-1) NaCl solution was added,and the mixture was kept under steady condition for5 min.In a high-salt environment,acetamiprid had a specifical interaction with the aptamer,gold nanoparticles aggregated due to loss of aptamer protection,and the color of the system changed from red to blue.A multifunctional microplate reader was used to measure the absorbance of the above system at 520,650 nm.The results showed that linearity relationship was kept in the range of 20-200μg·L^(-1) between mass concentration of acetamiprid and the ratio of absorbance at 520 nm and 650 nm,with detection limit of 1.13μg·L^(-1).A spkied recovery test was made on the blank Chinese herbal medicine at 3 concentration levels,giving recoveries ranged from91.1%to 105%,and RSDs(n=5)of measured values ranged from 1.1%to 4.8%.The proposed method was used for determination of acetamiprid in a variety of Chinese herbal medicines,and acetamiprid was detected in the 2 Chinese herbal medicines,with detection mass fractions of 329.10,125.22μg·kg^(-1).