Silicon microfabricated column with microfabricated differential mobility spectrometer for GC analysis of volatile organic compounds
Silicon microfabricated column with microfabricated differential mobility spectrometer for GC analysis of volatile organic compounds
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DOI：
10.1021/ac051216s
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发表时间：
2005-12-01
影响因子：
7.4
通讯作者：
Sacks, R
中科院分区：
文献类型：
--
作者：
Lambertus, GR;Fix, CS;Sacks, R
一条长3.0米、宽150微米、深240微米的通道被刻蚀在3.2厘米见方的硅片上，上面覆盖着一片吡喃硅片，再涂上一层二甲基聚硅氧烷固定相，用于挥发性有机化合物的GC分离。该塔产生类似于5500个理论板，在传统的对流烤箱中进行温度编程。该色谱柱通过加热传输线连接到微细加工的差动迁移率光谱仪。该光谱仪配备了一个镍-63源，用于分析物的常压化学电离。氮气或空气输送气体(流量300厘米(3)/分钟)驱动分析物离子通过细胞。该光谱仪在探测器单元中的一对电极之间利用不对称的射频(RF)电场工作。在每个射频周期中，离子迁移率在高场和低场之间交替(差动迁移率)。离子在电极之间振荡，只有具有适当差异迁移率的离子才能到达电池下游端的一对偏置收集器。扫描施加到RF电极之一的补偿电压，以允许具有不同微分迁移率的离子通过电池而不会在RF电极上被湮灭。该装置的一个独特特点是，在一次实验中既可以检测到正离子，也可以检测到负离子。对组合的微制色谱柱和检测器进行了评估，以分析具有各种功能的挥发性有机化合物。
A 3.0-m-long, 150-mu m-wide, 240-mu m-deep channel etched in a 3.2-cm-square silicon chip, covered with a Pyrex wafer, and coated with a dimethyl polysiloxane stationary phase is used for the GC separation of volatile organic compounds. The column, which generates similar to 5500 theoretical plates, is temperature-programmed in a conventional convection oven. The column is connected through a heated transfer line to a microfabricated differential mobility spectrometer. The spectrometer incorporates a Ni-63 source for atmospheric-pressure chemical ionization of the analytes. Nitrogen or air transport gas (flow 300 cm(3)/min) drives the analyte ions through the cell. The spectrometer operates with an asymmetric radio frequency (RF) electric field between a pair of electrodes in the detector cell. During each radio frequency cycle, the ion mobility alternates between a high-field and a low-field value (differential mobility). Ions oscillate between the electrodes, and only ions with an appropriate differential mobility reach a pair of biased collectors at the downstream end of the cell. A compensation voltage applied to one of the RF electrodes is scanned to allow ions with different differential mobilities to pass through the cell without being annihilated at the RF electrodes. A unique feature of the device is that both positive and negative ions are detected from a single experiment. The combined microfabricated column and detector is evaluated for the analysis of volatile organic compounds with a variety of functionalities.