https://www.selleckchem.com/products/bi-2852.html Mercury ion (Hg2+) is one of the most toxic heavy metal ions which will cause permanent damage to the brain and kidneys. So, it is important to develop a sensitive, simple and reliable approach to detect Hg2+. In this work, we report a surface-enhanced Raman scatting (SERS) sensor by decorating the inner wall of capillary with 4,4'-dipyridyl (Dpy) functionalized silver nanoparticles (AgNPs). The main advantage of this sensor is that it can collect samples directly by capillary force and carry out on-site analysis by combining portable Raman spectrometer. In the presence of Hg2+, the Dpy molecules would be separated from the surface of AgNPs and coordinated with Hg2+, resulting in a decrease in the SERS signal. A linear correlation of Raman intensity with Hg2+ concentrations from 1 to 100 part-per-billion (ppb) was obtained for quantitative analysis and the limit of detection (LOD) was determined to be 0.1 ppb. The good reproducibility and selectivity of the sensor were also demonstrated. In addition, the sensors were successfully applied to detect Hg2+ in real environmental water samples, and the sampling process provided operation convenience compared to conventional methods. These results indicated that these capillary sensors had great potential for Hg2+ detection in practical use. V.A well-designed naphthopyran-diaminomaleonitrile dyad (sensor 1) has been synthesized successfully, its molecular structure was well characterized by NMR and mass spectrometry. Sensor 1 exhibits excellent photochromic and photochromic fluorescence switch performance with reversible color change and good fatigue resistance upon alternating ultraviolet irradiation and thermal bleaching. In addition, sensor 1 displayed excellent fluorescent and colorimetric sensing ability towards Cu2+ ions with high selectivity and sensitivity. The addition of 5.0 equiv. of Cu2+ ions into sensor 1 (1 × 10-5) in CH3CN solution significantly quenched the