生物源揮發性有機化合物快速蒐集便攜式裝置之開發

Abstract

本研究旨在開發一套便攜式的生物源揮發性有機化合物（Biogenic Volatile Organic Compounds，BVOCs）氣體蒐集裝置，以實現野外環境下更貼近自然條件的氣體取樣。裝置採用 Push–Pull 架構，前端推氣、後端抽氣，並利用分流系統將氣流平均分配至多個通道。所有元件微型化後整合於工具箱內。供電系統支援行動電源與外接電源供應器，可供操作者自由切換，滿足室內外長時間運作之需求；機構設計上，上層為流速控制與吸附管更換區域，下層為幫浦與管路，有效降低操作時可能造成的干擾。所有機構設計皆為可拆卸式，有利於後續維護。 為減少操作者差異所致的取樣誤差，本裝置引入基於 Arduino Uno 的 PI 控制演算法，並以 Raspberry Pi 5 建置人機介面：使用者可透過螢幕設定目標流速、監測即時流速與剩餘蒐集時間；系統將 PWM（Pulse-width modulation） 控制訊號輸出至幫浦，並以經過RC濾波的流速回饋進行閉迴路調節。實驗結果顯示，在設定流速0.20-1.00 L/min 範圍內，裝置能於 7 s 內達成穩定，30分鐘內的總流量誤差小於 30 mL，長時間運作下相對標準差低於1%，成功驗證了穩定性與準確度。 綜合而言，本研究所開發之便攜式多通道氣體蒐集裝置兼具高效能、易操作與可維護性，能滿足實驗室與野外取樣需求，為後續生態化學監測提供了可靠之技術平台。

This study aims to develop a portable, dynamic sampling device for Biogenic Volatile Organic Compounds (BVOCs) to enable gas collection under natural field conditions. The device employs a Push–Pull configuration—air is pushed in at the front and drawn out at the rear—and uses a manifold system to distribute flow evenly across multiple channels. All core components have been miniaturized and integrated into a toolbox. The power system supports both portable battery and external power supply modes, which users can switch between freely to accommodate long duration operation indoors or outdoors. Structurally, the upper compartment houses the flow control module and adsorption tube exchange area, while the lower compartment contains the pump and tubing, effectively minimizing operational interference. All mechanical assemblies are designed for quick disassembly to facilitate maintenance. To reduce sampling error arising from operator variability, the device incorporates a PI control algorithm running on an Arduino Uno and provides a user interface implemented on a Raspberry Pi 5. Through the touchscreen interface, users can set the target flow rate and monitor real time flow and remaining collection time; the system outputs PWM control signals to the pump and uses flow feedback—filtered by an RC low pass circuit—for closed loop adjustment. Experimental results demonstrate that, across a setpoint range of 0.20–1.00 L/min, the device reaches stability within 7 s, maintains a total volume error under 30 mL, and exhibits a relative standard deviation below 1 % during extended operation, thereby validating its stability and accuracy. In summary, the portable, multi channel gas sampling device developed in this study combines high performance, ease of operation, and maintainability. It meets the requirements of both laboratory and field sampling and provides a reliable technical platform for future ecological chemistry monitoring.