Hexavalent chromium ions (Cr(VI)) possess inherent toxicity and propensity for bioaccumulation in the environment. Herein, a Cu-curcumin nanozyme was synthesized via a one-pot solvothermal method. Based on the high peroxidase-like activity of the Cu-curcumin nanozyme, a novel and economical colorimetric platform has been developed for Cr(VI) assay. In the presence of hydrogen peroxide (H₂O₂), the Cu-curcumin nanozyme can catalyze the transformation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) into the blue product oxTMB. 8-Hydroxyquinoline (8-HQ) can inhibit the catalysis of the Cu-curcumin/TMB/H₂O₂ system, causing the blue color to fade. With the addition of Cr(VI), the peroxidase-like activity of the Cu-curcumin nanozyme is increased significantly, leading to the restoration of the Cu-curcumin/TMB/H₂O₂ system color. After optimization of the experimental parameters, a novel colorimetric sensor for Cr(VI) assay has been successfully developed with a low limit of detection (LOD) of 31.5 nM, affirming its potential for accurate Cr(VI) quantification in environmental specimens. In addition, paper strips integrated with a smartphone platform enhance the versatility and portability of the Cr(VI) assay, achieving an LOD of 0.1 μM.

中文翻译：

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铜姜黄素纳米酶，用于通过基于过氧化物酶模拟活性的关-开策略检测 Cr（VI）


六价铬离子 （Cr（VI）） 具有固有的毒性和在环境中生物积累的倾向。在此，通过一锅法溶剂热法合成了铜姜黄素纳米酶。基于铜姜黄素纳米酶的高过氧化物酶样活性，开发了一种新颖且经济的比色平台用于 Cr（VI） 测定。在过氧化氢 （H₂O₂） 存在下，铜姜黄素纳米酶可以催化无色 3,3′，5,5′-四甲基联苯胺 （TMB） 转化为蓝色产物 oxTMB。8-羟基喹啉 （8-HQ） 可抑制铜姜黄素/TMB/H₂O₂ 系统的催化作用，导致蓝色褪色。随着 Cr（VI） 的加入，Cu-姜黄素纳米酶的过氧化物酶样活性显着增加，导致 Cu-姜黄素/TMB/H₂O₂ 系统颜色的恢复。经过实验参数优化，成功开发了一种用于 Cr（VI） 测定的新型比色传感器，其检测限 （LOD） 为 31.5 nM，证实了其在环境标本中准确定量 Cr（VI） 的潜力。此外，与智能手机平台集成的纸条增强了 Cr（VI） 分析的多功能性和便携性，实现了 0.1 μM 的 LOD。