甘蔗多酚抗氧化活性的DPPH、ABTS和FRAP法测定及测量不确定度评定OA

To determine and evaluate the antioxidant activity of sugarcane polyphenol extracts,establish a multi-index combined determination method applicable to sugarcane polyphenols,and systematically analyze and evaluate the measurement uncertainty of each determination method.Three classical in vitro antioxidant activity assays—the 2,2-diphenyl-1-picrylhydrazyl(DPPH)radical scavenging method,the 2,2ʹ-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS)radical scavenging method,and the ferric reducing antioxidant power(FRAP)method—were used to evaluate the antioxidant activity of sugarcane polyphenol extracts,with systematic validation of methodological parameters.All three methods showed excellent linearity,with correlation coefficients R2 greater than 0.999.Precision RSD was less than 2.0％,repeatability RSD was less than 3.5％,and stability was satisfactory.Spike recoveries ranged from 97.4％to 100.5％,and the limits of detection were 1.21,1.05 μg/mL,and 5.50 μmol/L,respectively.The DPPH radical scavenging rate was 78.32％±1.39％(k=2);ABTS radical scavenging rate was 85.47％±1.72％(k=2);and the FRAP value was(456.8±10.6)μmol/g(k=2),all at approximately 95％confidence level.The primary sources of measurement uncertainty were sample solution preparation,absorbance measurement,temperature control,and repeatability.The determination methods are accurate and reliable,and the measurement uncertainty evaluation provides technical support for quality control and standardized testing of sugarcane polyphenol antioxidant activity.