L-半胱氨酸修饰纳米金/纸芯片体系对手性多巴的快速检测

L-cysteine modified gold nanoparticles/paper chip system for rapid detection of chiral dopa

建立了一种基于纸芯片的L-多巴(L-Dopa)检测方法。通过氨基将L-半光氨酸修饰到纳米金粒子表面,制得L-半光氨酸-纳米金粒子(L-Cys-AuNPs),并对其进行表征。以纸芯片为平台,L-Cys-AuNPs通过氢键对L-Dopa发生特异性识别而发生团聚,溶液逐渐由红色变为蓝色。采用手机拍照,Photoshop软件分析图片,得红蓝通道色度比值(ΔR/B)。结果表明,在5~80μmol/L范围内,L-Dopa浓度与ΔR/B之间呈良好线性关系(R=0.9944),检测限4μmol/L。加标回收率在98%~102%之间;日内重复性和日间重复性相对标准偏差(RSD)分别为3.3%和3.8%。对实际样品DL-多巴中L-Dopa的含量进行测定,与标注值的误差在5%范围内。该方法可用于L-Dopa的检测。

A new detection method for L-Dopa based on paper chips was established. The L-Cys-AuNPs were characterized by their size, zeta potential, and UV-visible absorption spectra. The system had the high selectivity for the colorimetric detection of L-Dopa with the color changing from red to blue. The results were recorded using a common cell phone and subsequently analyzed using Photoshop software. A ratiometric color intensity method was designed for the quantification analysis. The ratio of color intensity at red channel and blue channel(ΔR/B) increases linearly with L-Dopa concentration in the range of 5 to 80 μmol/L(R=0.9944), with the limit of detection of 4 μmol/L. The spiked recoveries of samples were 98%-102%. The RSDs of inter-day and intra-day were 3.3% and 3.8%, respectively. Real samples were detected, and the error between the determination and the labeled value was within 5%. The method can be used to detect L-Dopa in real samples.