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A novel colorimetric assay based on the peroxidase-like properties of amino functionalized copper metal–organic framework nanoparticles for ascorbic acid sensing

Yao, Zhixia, Li, Zhen, Liu, Hanmeng, Liu, Yaosheng, Sun, Yujing, Li, Zhuang
Analytical methods 2019 v.11 no.12 pp. 1697-1706
absorbance, ascorbic acid, blood serum, color, colorimetry, coordination polymers, copper, copper nanoparticles, detection limit, humans, hydrogen peroxide, oxidation
A rapid and sensitive colorimetric strategy for the determination of ascorbic acid (AA) is presented, using amino functionalized copper metal–organic framework nanoparticles (Cu-BDC-NH₂ NPs) with effective intrinsic peroxidase-like properties. In our design, Cu-BDC-NH₂ NPs catalyze the H₂O₂ oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) generating blue-colored oxidized TMB (ox-TMB) with a significant absorbance at 655 nm in the UV-vis spectrum. AA can reduce ox-TMB, inducing a dramatic blue color fading and a decrease in absorbance. Under the optimal experimental conditions, this proposed system presents a good linear relationship (0.5–60 μM) and the detection limit is 0.15 μM. Repeatability, high selectivity and practicability are also well-studied, proving that the sensing system based on Cu-BDC-NH₂ NPs can be successfully applied for colorimetric detection of AA in human serum, food and pharmaceutical samples. The designed method can provide a highly selective and sensitive optical sensing system to detect AA and establish a new platform to develop extensive applications of metal–organic framework nanoparticles with enzyme-mimetic activity in colorimetric biosensing.