Abstract

To enhance the performance of a conventional pulse width modulation (PWM)-based microsampling system, a novel system was developed by bifurcating a fluidic path and by reusing the conventional components. A micro-metering valve was newly equipped to control the speed of the sample introduction, and a reflective optical sensor was used to detect the arrival of a sample. In addition, an analog logic circuit was designed to minimize the response time of the control system. This approach features precise microsampling, rapid response, and stable operation. To verify the volumetric sampling performance and to understand the operational characteristics, a series of experiments were performed. The results show that the aspirated volume was maintained at about 2.8 microliters and that the aspiration requires less than 0.3 seconds. Moreover, the sample removal operation was performed identical to a conventional PWM-based microsampling system. Because our spectrophotometer is operated automatically, the reduction of the sampling time is highly advantageous to measure many samples. Therefore, the total measurement time may be reduced proportional to the number of samples to be analyzed.

摘要

为了提高基于传统脉宽调制 (PWM) 的微采样系统的性能，通过分流流体路径和重复使用传统组件开发了一种新型系统。新增微量计量阀控制进样速度，反射式光学传感器检测进样速度。此外，还设计了一个模拟逻辑电路，以最大限度地缩短控制系统的响应时间。这种方法具有精确的微量采样、快速的响应和稳定的操作。为了验证体积采样性能并了解操作特性，进行了一系列实验。结果表明，吸入的体积保持在大约 2.8 微升，并且吸入所需的时间少于 0.3 秒。而且，样本移除操作的执行与传统的基于 PWM 的微采样系统相同。由于我们的分光光度计是自动操作的，采样时间的减少对于测量大量样品非常有利。因此，总测量时间可以与要分析的样本数量成比例地减少。