Study On The Targeted, Highly Sensitive And Rapid Detection Of Plant Polyphenols Based On Gold Nanoparticles

Plant polyphenols are phenolic secondary metabolites in plant with important medicinal values, such as antioxidant, antibacterial, antitumor and other biological activities, etc. The detection of polyphenols is important for the production and quality control of polyphenols products as well as the identification and screening of breeding varieties. Traditional methods for the determination of polyphenols content usually cost much time, reagent and labor, as well as low targeting and precision. Therefore, it is hard for them meet the demands of the rapid, low consumption and highly efficient detection in processing and utilization of plant. Gold nanoparticles (AuNPs) have high extinction coefficients and unique optical and electromagnetic properties, which has been widely used in improving the sensitivity of the biosensor. However, the application of AuNPs to polyphenols has not been reported. On the basis of these, we focus on AuNPs to develop rapid and efficient methods for the detection of polyphenols by selecting sinapic acid and sinapine as model analytes.The following summarize the conclusions of two aspects.1.An accurate and rapid method for the detection of sinapic acid and total polyphenols has been developed based on antioxidant of polyphenols and high negative charge on the surface of AuNPs. This proposed method is simple, rapid and highly sensitive as well as has good stability. The determination of sinapic acid and total polyphenols can be realized in visualization with the limit detection of 0.012?g mL-1 and the precision of 1%. Compared to the highly sensitive electrochemical and fluorescent methods, this method avoids complicated reagents preparation and label process as well as enhances the sensitivity with one magnitude. Besides, the proposed method is applied to rapeseed oil with a good recovery and the detection results have good agreement with Folin-Ciocalteu colorimetric method.2. Sinapine is phenolic secondary metabolites in plant with important biological activities. The above experiments show that sinapine is easy to make AuNPs aggregation by the interaction between SCN- and AuNPs. As a result, the bareness AuNPs has some limitation in the detection of this kind polyphenols. In order to solve this problem, a highly targeted, sensitive and rapid method for the detection of sinapine based on modified AuNPs. The limit detection and precision of this proposed method is 8 ng mL-1 and 3.4%, respectively. Compared to the highly sensitive electrochemical method, this method effectively avoids complicated reagents preparation and label process as well as saves detection time and cost, enhances the sensitivity with one magnitude. Besides, the proposed method is applied to rapeseed meal with a good recovery and the detection results have good agreement with HPLC method.