为了实现离子源和高场非对称波形离子迁移谱的其它部分的集成, 本文基于PCB工艺设计了一种新型的针-环离子源结构。该结构主要由针电极、环电极、进气底座以及针固定底座组成, 针电极采用针尖曲率半径为28 μm的不锈钢针作为放电阴极, 直径为3 mm、高度为16 mm的铜环作为放电阳极。放电特性实验结果表明: 针-环离子源在放电电压-2 kV和-2.8 kV时, 分别进入了电晕放电和辉光放电, 能够在大气压环境下实现稳定放电。在载气流速为1.5 L/min、方波射频电压幅值为300 V的条件下, 两者FAIMS谱图中补偿电压基本相同, 且采用针-环离子源和紫外灯离子源所得的FAIMS谱图的电流峰值分别为64 pA和45 pA, 由此表明集成式针-环离子源FAIMS系统能够稳定工作, 且相比紫外灯离子源集成性更好, 电流信号更强。

A needle-ring ion source structure based on printed circuit board technology was designed to integrate an ion source with a High-field Asymmetric Ion Mobility Spectrometry (FAIMS) structure, which was composed of a needle electrode, loop electrode, air inflow pedestal, and fixed needle pedestal. A stainless steel needle tip with a diameter of 28 μm was used as the cathode, and a copper loop with a diameter of 3 mm and length of 16 mm was used as the anode. A discharge property experiment shows that corona and glow discharges are realized through discharge voltages of -2 kV and -2.8 kV, respectively, proving that the stable discharge state could be obtained in ambient air. Comparing the FAIMS system using a UV-lamp ion source with the FAIMS system using a needle-ring ion source, the compensation voltages in the FAIMS spectrum are nearly the same under the conditions of a carrier gas flow rate of 1.5 L/min and a high-field rectangular radio peak-to-peak voltage of 300 V. However, the electric currents are 64 pA and 45 pA for the needle-ring and UV-lamp ion sources, respectively. Experimental results thus reveal that the integrated FAIMS using the needle-ring ion source can work stably and that it has a better integration property and stronger signal when compared to a UV-lamp ion source.