Teerasong Saowapak, Jinnarak Amornrassamee, Chaneam Sumonmarn, Wilairat Prapin, Nacapricha Duangjai
Department of Chemistry and Applied Analytical Chemistry Research Unit, Faculty of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520 Thailand; Flow Innovation-Research for Science and Technology Laboratories (FIRST Labs), 10400 Thailand.
Department of Chemistry and Applied Analytical Chemistry Research Unit, Faculty of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520 Thailand.
Talanta. 2017 Aug 1;170:193-198. doi: 10.1016/j.talanta.2017.04.009. Epub 2017 Apr 5.
A simple and rapid method for measurement of total antioxidant capacity (TAC) was developed. In this work, gallic acid was used as the antioxidant standard. Poly(vinyl alcohol) embedded silver nanoparticles (PVA-AgNPs) were employed as a colorimetric sensor. The detection principle was based on the seed-mediated nanoparticle growth technique. The PVA-AgNPs act as a catalyst in the reduction of Ag by gallic acid by providing nucleation seeds. Ag was reduced to Ag° and accumulated on the PVA-AgNP surface, leading to an increase in the size of particles. The absorbance of the colloidal solution was drastically enhanced with a small red shift. Under optimal conditions, a linear response was established between the change in absorbance and the TAC value expressed in terms of gallic acid equivalents. The linear range was from 25 to 200μM with a detection limit of 22.1μM. Satisfactory precision was obtained with % relative standard deviation (RSD) of 2.17. The developed sensor was successfully applied for TAC assessment of commercial ginger products. The PVA-AgNP sensor offers rapid analysis (within 5min) compared to other nanoparticle-based antioxidant assays. Synthesis of the particles and assay involved less-toxic chemicals, and is therefore a "greener" method.
开发了一种简单快速的总抗氧化能力（TAC）测量方法。在这项工作中，没食子酸用作抗氧化剂标准品。聚乙烯醇包埋的银纳米颗粒（PVA-AgNPs）用作比色传感器。检测原理基于种子介导的纳米颗粒生长技术。PVA-AgNPs通过提供成核种子，在没食子酸将Ag还原的过程中起催化剂作用。Ag被还原为Ag°并积累在PVA-AgNP表面，导致颗粒尺寸增大。胶体溶液的吸光度急剧增强，伴有小的红移。在最佳条件下，吸光度变化与以没食子酸当量表示的TAC值之间建立了线性响应。线性范围为25至200μM，检测限为22.1μM。相对标准偏差（RSD）为2.17，获得了令人满意的精密度。所开发的传感器成功应用于商业姜产品的TAC评估。与其他基于纳米颗粒的抗氧化剂测定方法相比，PVA-AgNP传感器提供快速分析（5分钟内）。颗粒的合成和测定涉及毒性较小的化学物质，因此是一种“更绿色”的方法。
