A simple, rapid and sensitive colorimetric method has been developed for the detection of Cd²⁺ using 2,6-dimercaptopurine-modified gold nanoparticles. In the presence of Cd²⁺, gold nanoparticles functionalized with 2,6-dimercaptopurine were aggregated via chelation between the metal ion and the ligand, accompanied by a color change from red to blue observed with the naked eye. Further, the solution of 2,6-dimercaptopurine-modified gold nanoparticles was monitored using a UV-Vis spectrometer. Under optimized conditions, good linearity varying from 0.75 to 3.0 μM was obtained with a correlation coefficient (R) of 0.996 along with a limit of detection of 32.7 nM. The recoveries were 88.0–112.0% in real samples, and the results agree well with those acquired by atomic absorption spectroscopy with a graphite furnace. The new approach was successfully applied to the determination of Cd²⁺ in milk, honey, lake water, serum, and urine samples.

中文翻译：

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2,6-二巯基嘌呤功能化的金纳米颗粒，用于食品，生物和环境样品中的镉（II）的灵敏和选择性比色测定

已开发出一种简单，快速，灵敏的比色法，用于使用2，6-二巯基嘌呤修饰的金纳米粒子检测Cd ²⁺。在Cd ²⁺存在下，被2,6-二巯基嘌呤官能化的金纳米颗粒通过金属离子与配体之间的螯合而聚集，并伴随着用肉眼观察到的从红色到蓝色的颜色变化。此外，使用UV-Vis光谱仪监测2，6-二巯基嘌呤修饰的金纳米颗粒的溶液。在优化的条件下，具有0.75至3.0μM的良好线性，相关系数为（R）为0.996，检出限为32.7 nM。实际样品中的回收率为88.0–112.0％，结果与石墨炉原子吸收光谱法获得的结果吻合良好。该新方法已成功应用于牛奶，蜂蜜，湖水，血清和尿液样品中Cd ^2+的测定。