氧化锌纳米颗粒增强鲁米诺-EDTA化学发光测定咖啡酸

Determination of Caffeic Acid Based on ZnO Nanoparticles Enhanced Luminol-EDTA Chemiluminescence

在ZnO纳米颗粒（ ZnO nanoparticles, ZnO NPs）和EDTA存在的条件下,无需外加氧化剂,鲁米诺（ Luminol）即能产生很强的化学发光,由此建立了化学发光体系Luminol-EDTA-ZnO NPs。基于咖啡酸能够有效抑制Luminol-EDTA-ZnO NPs化学发光,结合流动注射技术测定了咖啡酸含量。在最佳的实验条件下,咖啡酸浓度在1.0x10-7-1.0x10-5 mol/L范围内,相对发光强度与咖啡酸浓度对数分段呈线性关系,检出限为1.8x10-8 mol/L （3δ）,对4.0x10-7 mol/L咖啡酸平行测定11次,相对标准偏差（RSD）为3.5%。利用本方法测定片剂中咖啡酸的含量,回收率为97%-101%。

In the presence of ZnO nanoparticles （ ZnO NPs ） and EDTA, luminol could produce strong chemiluminescence （ CL） without any oxidant. Therefore, a new CL system was established based on luminol-EDTA-ZnO NPs. As caffeic acid could strongly inhibit the CL, a flow injection CL method for the determination of caffeic acid was proposed. Under the optimized conditions, the relative CL intensity was linear over the logarithm of concentration of caffeic acid ranging from 1 . 0x10-7 mol/L to 1 . 0x10-5 mol/L with the detection limit of 1. 8x10-8 mol/L （3σ）. The relative standard deviation （RSD） for the determination of 4 . 0x10-7 mol/L caffeic acid was 3 . 5% （ n=11 ） . The new method was successfully applied to determine the caffeic acid content in the tablets with the recoveries in the range of 97%-101%.