Tea polyphenols (TPPs), as the most important functional component in tea extract, are easily contaminated by many heavy metals during tea processing, transportation and storage. TPPs with heavy metals can cause serious health problems and economic losses. In this study, to efficiently remove heavy metals from TPPs without affecting their active compounds and antioxidant functions, we prepared the amino-functionalized modified silica gel (AFSG) to remove Pb, Cu and Cd from TPPs, and determined removal rate of heavy metals, total polyphenolic content (TPC) and antioxidant activity of TPPs before and after adsorption. The static adsorption experiments showed that the adsorption isotherms were consistent with Langmuir model, in which the maximum sorption capacities of Pb, Cu and Cd were 140.23, 100.75 and 48.03 mg/g (25 °C, pH 5.0), respectively. Compared with before adsorption, the contents of Pb, Cu and Cd in 3 TPPs samples decreased significantly after adsorption on AFSG column (p < 0.01). However, the TPC and antioxidant capacity of the 3 TPPs samples had no significant effect before and after adsorption (p > 0.05). Meanwhile, the desorption and regeneration experiment showed that after 6 times of cyclic adsorption, the removal ability of Pb, Cu and Cd in TPPs by AFSG column could still reach 98.1%, 99.59% and 99.78%, respectively. Therefore, these results suggested that AFSG column could effectively remove heavy metals from TPPs without affecting the TPC and its antioxidant activity, it has potential applications in the removal and detection of heavy metals in TPPs.

中文翻译：

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用氨基官能化硅胶有效去除茶多酚提取物中的重金属

茶多酚（TPP）作为茶提取物中最重要的功能成分，在茶的加工，运输和储存过程中很容易被许多重金属污染。具有重金属的TPP可能导致严重的健康问题和经济损失。在这项研究中，为了有效地从TPP中去除重金属而不影响其活性化合物和抗氧化功能，我们制备了氨基官能化改性硅胶（AFSG）从TPP中去除Pb，Cu和Cd，并确定了重金属的去除率， TPP吸附前后的总多酚含量（TPC）和抗氧化活性。静态吸附实验表明，吸附等温线与Langmuir模型一致，其中Pb，Cu和Cd的最大吸附容量分别为140.23、100.75和48.03 mg / g（25°C，pH 5.0）。与吸附前相比，在AFSG柱上吸附后3种TPPs中的Pb，Cu和Cd含量显着降低（p <0.01）。但是，这3种TPP样品的TPC和抗氧化能力在吸附前后均无显着影响（p> 0.05）。同时，解吸再生实验表明，经过6次循环吸附，AFSG柱对TPPs中Pb，Cu和Cd的去除能力仍分别达到98.1％，99.59％和99.78％。因此，这些结果表明AFSG色谱柱可以有效地从TPP中去除重金属而不影响TPC及其抗氧化活性，在去除和检测TPP中的重金属方面具有潜在的应用前景。在AFSG柱上吸附后，3种TPPs样品中的Cu和Cd显着降低（p <0.01）。但是，这3种TPP样品的TPC和抗氧化能力在吸附前后均无显着影响（p> 0.05）。同时，解吸再生实验表明，经过6次循环吸附，AFSG柱对TPPs中Pb，Cu和Cd的去除能力仍分别达到98.1％，99.59％和99.78％。因此，这些结果表明AFSG色谱柱可以有效地从TPP中去除重金属而不影响TPC及其抗氧化活性，它在去除和检测TPP中的重金属方面具有潜在的应用前景。在AFSG柱上吸附后，3种TPPs样品中的Cu和Cd显着降低（p <0.01）。但是，这3种TPP样品的TPC和抗氧化能力在吸附前后均无显着影响（p> 0.05）。同时，解吸再生实验表明，经过6次循环吸附，AFSG柱对TPPs中Pb，Cu和Cd的去除能力仍分别达到98.1％，99.59％和99.78％。因此，这些结果表明AFSG色谱柱可以有效地从TPP中去除重金属而不影响TPC及其抗氧化活性，它在去除和检测TPP中的重金属方面具有潜在的应用前景。同时，解吸再生实验表明，经过6次循环吸附，AFSG柱对TPPs中Pb，Cu和Cd的去除能力仍分别达到98.1％，99.59％和99.78％。因此，这些结果表明AFSG色谱柱可以有效地从TPP中去除重金属而不影响TPC及其抗氧化活性，它在去除和检测TPP中的重金属方面具有潜在的应用前景。同时，解吸再生实验表明，经过6次循环吸附，AFSG柱对TPPs中Pb，Cu和Cd的去除能力仍分别达到98.1％，99.59％和99.78％。因此，这些结果表明AFSG色谱柱可以有效地从TPP中去除重金属而不影响TPC及其抗氧化活性，在去除和检测TPP中的重金属方面具有潜在的应用前景。