基于液芯波导原理的微流控芯片长光程光度检测系统

提出了一种基于液芯波导(Liquidcorewaveguide,LCW)原理的微流控芯片吸收光度检测系统.通过芯片与外界接口技术实现液芯波导管与芯片的耦合,建立了芯片上长光程(毫米至厘米级)吸收光度检测池.采用邻菲啉-铁(Ⅱ)显色体系验证系统分析性能,以5.5cm外覆TeflonAF液芯波导管作为检测池(检测池体积240nL)时,芯片系统的检测线性范围为0.03～50μmol/L,对邻菲啉-铁(Ⅱ)配合物的检出限为8nmol/L,检测池有效光程达1.7cm,分析精度RSD(n=5)为0.8%.

A Microfluidic Chip for Absorbance Measurements with Long Optical Path-length Based on a Liquid-core Waveguide Technique

In this work, a system for high sensitivity absorbance measurements on microfluidic chips was developed with a detection volume of 240 nL. Long optical path-length(1.7 cm effective path length) was achieved on the chip by using an integrated liquid core waveguide(LCW) silica capillary coated with Teflon AF. The performance of the system was tested by using o-phenanthroline-Fe(Ⅱ) complex as a model sample with spectrophotometric detection, achieving a detection limit of 8 nmol/L for the complex. The absorbance of samples ranging from 0.03—50 μmol/L is linear(R 2=0.999 4) and showed good repeatability with a RSD of 0.8%(n=5). The sensitivity of the chip-LCW system was a factor of 1.7 higher than conventional spectrophotometry using a 1 cm cell. The present system can be applied in continous flow or flow injection analysis systems.