基于Os-Ir纳米复合材料的过氧化物酶模拟活性快速灵敏比色检测抗坏血酸

Rapid and Sensitive Colorimetric Detection of Ascorbic Acid Based on Os-Ir Nanocomposite with Peroxidase-Mimicking Activity

摘要:

抗坏血酸在维护人体健康、预防疾病等方面扮演着不可或缺的角色，准确测定食品、保健品等中抗坏血酸含量至关重要。近年来，研究者们致力于开发基于纳米酶的简单、快速、高灵敏度的抗坏血酸检测方法。然而，目前还未有关于Os-Ir纳米酶及其应用于抗坏血酸检测的研究报道。因此，为丰富纳米酶种类，采用还原法合成了粒径约为34 nm且形态均一的球状Os-Ir纳米复合物，并将其用于抗坏血酸检测，开发出一种新的、简单、有效、准确、快速检测抗坏血酸的方法。结果表明，Os-Ir纳米复合物具有优异的过氧化物酶模拟活性，其米氏常数（K_m）为2.98 mmol?L^-1、最大反应速率（V_max）为5.62 mmol?L^-1min^-1。在此基础上，通过实验确定了Os-Ir纳米酶用于抗坏血酸检测的最佳传感条件，如反应体系pH值5.5、反应温度40 ℃、Os-Ir纳米酶的原液稀释倍数256倍、反应时间5 min。在最优检测条件下，所开发的基于Os-Ir纳米酶的抗坏血酸检测方法获得了较宽的检测范围（0—147.06 μmol?L^-1）和较高的检测灵敏度（检测限为0.31 μmol?L^-1、定量限为1.03 μmol?L^-1）。通过在3款不同饮料中进行加标回收实验验证了所开发方法在实际样品检测中具有相当的可靠性和可行性，其中回收率为95.15%—103.22％、相对标准偏差为1.92%—8.60%，均在可接受标准范围内。研究开发的基于Os-Ir纳米酶的比色检测方法对抗坏血酸实现了简单、便捷、快速、灵敏的检测，在食品监制、生物医药等领域中具有较高的潜在应用价值。

Abstract:

Ascorbic acid plays an indispensable role in the maintenance of human health and prevention of diseases. The accurate determination of ascorbic acid in food， health products， etc. is crucial. In recent years， researchers have been working on the development of simple， rapid， and highly sensitive nanozyme-based assays for ascorbic acid. However， there is currently no research report on Os-Ir nanozyme and its use for ascorbic acid detection. Therefore， to enrich the variety of nanozymes and develop a new， simple， effective， accurate and rapid method for the detection of ascorbic acid， a uniform spherical shaped Os-Ir nanocomposite with a particle size of about 34 nm was synthesized by reduction method in this work. The nanocomposite was experimentally demonstrated to possess excellent peroxidase-mimicking activity with the Michaelis constant （K_m） of 2.98 mmol?L^-1 and the maximum reaction rate （V_max） of 5.62 mmol?L^-1?min^-1. On this basis， the optimal sensing conditions of Os-Ir nanozyme for ascorbic acid detection were determined， including pH 5.5 of reaction system， reaction temperature of 40 ℃， 256-fold dilution of Os-Ir nanozyme stock solution， and reaction time of 5 min. Under these conditions， the developed Os-Ir nanozyme-based ascorbic acid assay obtained wide detection range （0—147.06 μmol?L^-1） and high detection sensitivity， with the limit of detection of 0.31 μmol?L^-1 and the limit of quantification of 1.03 μmol?L^-1. Finally， the spiked recovery experiments in three different beverages verified that the developed method possessed reliability and feasibility in actual sample detection. The measured recovery rate range was 95.15% to 103.22% and the relative standard deviation was 1.92% to 8.60%. In conclusion， the colorimetric method based on Os-Ir nanozyme achieved simple， convenient， rapid and sensitive detection of ascorbic acid， and possessed potential applications in the fields of food supervision and biomedicine.