Simultaneous laser-induced fluorescence and contactless-conductivity detection for microfluidic chip

A combined detection system involving simultaneous LIF and contacfless-conductometric measurements at the same place of the microfluidic chip was described. The LIF measurement was designed according to the confocal principle and a moveable contactless-conduetivity detector was used in C^4D. Both measurements were mutually independent and advantageous in analyses of mixtures. Various experimental parameters affecting the response were examined and optimized. The performances were demonstrated by simultaneous detection of Rhodamine B. And the results showed that the combined detection system could be used sensitively and reliably.

基于多层PCB的ME-C^(4)D电极设计及其性能研究

文章针对微芯片电泳电容耦合式非接触电导检测(microchip electrophoresis-capacitively coupled contactless conductivity detection, ME-C^(4)D)电极存在检测信号信噪比低、稳定性差的问题,提出一种基于多层印制电路板(printed circuit board, PCB)的ME-C~4D电极。通过与相同结构的单层PCB电极对比实验发现,多层PCB电极的噪声最大电平降低至5.5 mV、信噪比提升1倍,且检测信号具有较好的稳定性。通过实验对多层PCB电极结构参数进行优化,使检测系统对K^(+)、Na^(+)、Li^(+)3种离子混合溶液的检测限和离子浓度分辨能力达到0.050 mmol/L,且检测结果具有较好的线性度和可重复性。实验证明,采用多层PCB电极,不仅改善了ME-C^(4)D系统的检测灵敏度和离子浓度分辨率,同时扩大了系统的最佳离子浓度检测范围。

基于SoPC的电泳芯片电导检测系统

探讨了一种基于SoPC的电泳芯片电导检测系统设计方案。采用MAX038函数发生器产生同步的正交信号源,采用双差分减法器实现阻抗到电压的变换,并利用双相锁定放大器实现电导幅值及相位检测,以FPGA内嵌NiosII软核处理器为系统控制核心,运用SoPC Builder定制高速采集控制器、FFT控制器以及运用IP核FFTV2.1.3构建实时高速长度为1 024点的FFT变换模块实现电泳芯片电容耦合非接触电导时、频域分析。文中具体阐述了系统软、硬件架构及自定制NiosII处理的FFT算法指令等。仿真结果表明:该方案能进行复杂数据处理,具有快速实时处理能力,能有效保证系统的抗干扰性和测量准确度。