Abstract：
A water-soluble colorimetric chemosensor NHOP ((E)-1-(2-(2-(2-hydroxy-5-nitrobenzylidene)hydrazineyl)-2-oxoethyl)pyridin-1-ium) chloride) was developed for the sequential probing of Cu2+ and S2-. NHOP underwent a color change from pale yellow to colorless in the presence of Cu2+ in pure water. The binding ratio between NHOP and Cu2+ was confirmed to be 1:1 by the Job plot and ESI-MS (electrospray ionization mass spectrometry). The detection limit of NHOP for Cu2+ was calculated as 0.15 μM, which was far below the EPA (Environmental Protection Agency) standard (20 μM). The NHOP-coated test strip was able to easily monitor Cu2+ in real-time. Meanwhile, the NHOP-Cu2+ complex reverted from colorless to pale yellow in the presence of S2- through the demetallation. The stoichiometric ratio between NHOP-Cu2+ and S2- was determined to be 1:1 by analyzing the Job plot and ESI-MS. The detection limit of NHOP-Cu2+ for S2- was calculated as 0.29 μM, which was very below the WHO (World Health Organization) guideline (14.7 μM). NHOP successfully achieved the quantification for Cu2+ and S2- in water samples. NHOP could work as a sequential probe for Cu2+ and S2- at the biological pH range (7.0-8.4). Moreover, NHOP could successively probe Cu2+ and S2- at least three cycles because of its reversible property. The detection mechanisms of NHOP for Cu2+ and NHOP-Cu2+ for S2- were demonstrated with Job plot, ESI-MS, and DFT (density functional theory) calculations. Therefore, NHOP could work as an efficient sequential probe for Cu2+ and S2- in environmental systems.
摘要：
开发了水溶性比色化学传感器NHOP（（E）-1-（2-（2-（2-羟基-5-硝基亚苄基）肼基）-2-氧代乙基）吡啶-1-铵）氯化物，用于顺序探测Cu2和S2-。在纯水中存在Cu2+的情况下,NHOP经历了从浅黄色到无色的颜色变化。通过Job图和ESI-MS(电喷雾电离质谱)确认NHOP和Cu2+之间的结合比为1:1。NHOP对Cu2+的检出限计算为0.15μM，远低于EPA（环境保护局）标准（20μM）。涂覆有NHOP的测试条能够容易地实时监测Cu2+。同时,在S2-存在下，NHOP-Cu2复合物通过脱金属从无色恢复为浅黄色。通过分析Job图和ESI-MS确定NHOP-Cu2和S2-之间的化学计量比为1：1。NHOP-Cu2+对S2-的检出限计算为0.29μM，这远远低于WHO（世界卫生组织）指南（14.7μM）。NHOP成功实现了对水样中Cu2+和S2-的定量。在生物pH范围（7.0-8.4）下，NHOP可以作为Cu2和S2-的顺序探针。此外，由于其可逆性，NHOP可以连续探测Cu2和S2-至少三个周期。通过Job图证明了NHOP对Cu2和NHOP-Cu2对S2的检测机制。ESI-MS,和DFT(密度泛函理论)计算。因此,NHOP可以作为环境系统中Cu2和S2-的有效序列探针。
