自製微電漿氣相層析儀偵測器在不同載流氣體下對無機分子之感應特性探討

Abstract

本研究製作一微電漿氣體偵測器，應用於氣相層析儀進行無機氣體之檢測，偵測器主要是由石英管及兩個不鏽鋼針頭製作而成，將高壓產生器連接至兩電極，以氬氣、氮氣及空氣作為載流氣體，施加4.23-5.28 kV與22.7 kHz之高壓交流電源，激發背景氣體以產生電漿。當待測物通過電漿放電區域時，以紫外光/可見光光譜儀分析放射光譜之特定波長範圍產生之光強度變化，再進一步最佳化光譜儀積分時間、載流氣體流速及電場梯度等實驗參數。於此最佳化條件下，以氬氣為載流氣體時可定量分析氫氣、一氧化碳、二氧化碳、硫化氫及二氧化硫；以氮氣為載流氣體時可定量分析氫氣、一氧化碳及二氧化碳；以空氣為載流氣體時可定量分析一氧化碳及二氧化碳。以上用不同載流氣體進行不同待測物之量測，均具有良好的線性關係，R²＞0.993。本研究製作之微電漿氣體偵測器具有裝置微小、構造簡單及高靈敏度等優點。當以價格相對低廉之氮氣為載流氣體時，氫氣之偵測下限可達到43 pg，勝於以氬氣為載流氣體時之98 pg。期許未來此微電漿偵測器能夠與微型氣相層析儀結合，並進行更多面向的應用。

In this study, a microplasma gas detector was developed and applied to the detection of inorganic gases via gas chromatography. The detector was constructed using a quartz tube and two stainless steel needle electrodes. A high-voltage AC power source (4.23–5.28 kV, 22.7 kHz) was applied to the electrodes to generate plasma by exciting the background gases—argon, nitrogen, or air—as the carrier gas. As target analytes passed through the plasma discharge region, the emission spectra were monitored using a UV-Vis spectrometer. The detection was based on variations in light intensity at specific wavelengths, and experimental parameters—including spectrometer integration time, carrier gas flow rate, and electric field gradient—were optimized accordingly. Under the optimized conditions, quantitative analysis of various gases was successfully performed. Using argon as the carrier gas, hydrogen, carbon monoxide, carbon dioxide, hydrogen sulfide, and sulfur dioxide could be detected. With nitrogen, hydrogen, carbon monoxide, and carbon dioxide were quantified. With air, detection was limited to carbon monoxide and carbon dioxide. In all cases, excellent linearity was achieved (R²> 0.993). The proposed microplasma gas detector offers advantages such as compact size, simple design, and high sensitivity. Notably, when nitrogen—a more cost-effective carrier gas—was used, the detection limit for hydrogen reached as low as 43 pg, outperforming the 98 pg limit achieved with argon. This demonstrates the detector’s potential for integration with miniature gas chromatography systems and for broader analytical applications in the future.