流动注射化学发光法测定槐米中槲皮素

在碱性溶液中槲皮素对过氧化氢氧化鲁米诺而产生的化学发光(CL)具有很强的抑制作用,且其CL强度的减弱程度与槲皮素浓度之间在一定的范围内呈线性关系。据此,并结合应用流动注射(FI)技术,提出了FI-CL测定槐米中槲皮素含量的方法。反应体系中所用试剂的最佳浓度为:①cH2O2=0.2mol.L-1;②c鲁米诺=8.5×10-4mol.L-1;③cNaOH=0.01mol.L-1。对槲皮素测定的线性范围为2.65×10-6～5.31×10-4mol.L-1之间,其检出限(3s/k)为9.26×10-7mol.L-1。用4×10-4mol.L-1槲皮素标准溶液进行精密度试验,测得相对标准偏差(n=11)为3.0%。分析试样时,先从槐米在pH 8～9的碱性溶液中提取芦丁,然后在微酸性(pH 5)溶液中使芦丁水解得到槲皮素粗品。将此粗品经反复重结晶得到槲皮素纯品,溶于乙醇(40+60)溶液中制成溶液,用于FI-CL分析。

FI-CL Determination of Quercetin in Flos Sophorae Immaturus

The chemiluminescence of oxidation of luminol by hydrogen peroxide in an alkaline medium was found to be inhibited strongly by quercetin,and the magnitude of decrease of CL intensity was found to keep linear relationship with the concentration of quercetin in a definite range.Based on this fact and combining the use of flow-injection technique,a method of FI-CL determination of quercetin in flos sophorae immaturus was proposed.The optimum concentration of reagents used in the reaction system were as follows: ① cH2O2=0.2 mol·L-1;② cluminol=8.5×10-4mol·L-1;and ③ cNaOH=0.01 mol·L-1.Range of linearity of quercetin was found between 2.65×10-6~5.31×10-4mol·L-1,with value of detection limit(3s/k) of 9.26×10-7mol·L-1.Value of RSD(n=11) found with 4×10-4mol·L-1 of quercetin was 3.0%.The sample of flos sophorae immaturus was pretreated by first extraction of rutin from the sample in an alkaline solution of pH 8-9,and then the rutin was hydrolyzed in a slightly acidic solution of pH 5 to give crude quercetin,which,after purification by re-crystallization,was dissolved in C2H5OH-H2O(40+60) solution and used for FI-CL analysis.