基于Co-MOFs衍生物用于L-Cys的比色和智能手机双模检测

Co-MOFs derivative for dual-mode detection of L-Cys based on colorimetric analysis and smartphone

采用室温合成-热解法制备了一种具有类过氧化物酶性质的金属钴有机框架衍生纤维棒状碳材料(Co-DM)。利用SEM、TEM、XRD和XPS对其形貌、结构及元素组成进行了表征。通过活性氧捕获实验研究了其催化机理,Co-DM可催化H2O2使其释放出超氧阴离子自由基(·O_(2)^(-))和羟基自由基(·OH),从而使无色的显色底物3,3’,5,5’-四甲基联苯胺(TMB)氧化成蓝色的氧化态产物(ox TMB),在652 nm处有最大的紫外吸收峰;而L-半胱氨酸(L-Cys)具有抗氧化性,能够还原ox TMB使蓝色褪色。基于此原理建立了一种检测L-Cys的比色检测方法。在pH=4.0、温度为40℃的最优条件下,L-Cys的浓度与652 nm处的吸光度在0.1~15.0μmol/L范围呈线性关系,检出限(LOD)为0.35μmol/L。此外,借助自制的智能手机光学设备和Color Garb软件,通过记录不同浓度L-Cys下溶液在白色(0,0,0)至黑色(255,255,255)范围内颜色变化的特征值R(红)、G(绿)、B(蓝)值,建立了Co-DM的相对活性与颜色特征值的定量关系,检测范围为0.1~70.0μmol/L,LOD为0.27μmol/L。该方法还成功地应用于临床人血清中L-Cys的检测,回收率在94.0%~101.5%之间。

A metal-cobalt organic framework-derived fibrous rod-like carbon material(Co-DM)with peroxidase-like properties was synthesized via room-temperature synthesis-pyrolysis method.The Co-DM obtained was characterized by SEM,TEM,XRD and XPS then for analyses on morphology,structure and elemental composition,and active oxygen capture experiment was further conducted for investigation of its catalytic mechanism.It was found that H2O2 under the catalysis of Co-DM released superoxide anion radicals(·O_(2)^(-))and hydroxyl radicals(·OH),thus oxidizing the colorless chromogenic substrate 3,3',5,5'-tetramethylbenzidine(TMB)to blue oxidation state product(oxTMB)with the largest adsorption peak at 652 nm.Since L-cysteine(L-Cys),with antioxidant properties,could reduce oxTMB thus leading the blue color product back to colorless,a colorimetric method for L-Cys detection was accordingly established.Under the optimal conditions of pH=4.0,temperature of 40℃,the concentration of L-Cys in the range of 0.1~15.0μmol/L showed a linear relationship with absorbance at 652 nm,and the limit of detection(LOD)was 0.35μmol/L.In addition,the quantitative relationship between the relative activity of Co-DM and the color characteristic values was established by recording the characteristic values R(red),G(green), and B (blue) values of color change in the range of white (0, 0, 0) to black (255, 255, 255) for solutions at different concentrations of L-Cys with the aid of a homemade smartphone optical device and Color Garb software. The detection range was 0.1~70.0 μmol/L and the LOD was 0.27 μmol/L. This method was also successfully applied in the detection of L-Cys in clinical human serum, with recovery rate between 94.0%~101.5%.