Collin William R, Bondy Amy, Paul Dibyadeep, Kurabayashi Katsuo, Zellers Edward T
Department of Chemistry, University of Michigan , Ann Arbor, Michigan 48109-1055, United States.
Anal Chem. 2015 Feb 3;87(3):1630-7. doi: 10.1021/ac5032226. Epub 2015 Jan 15.
The development and characterization of a microanalytical subsystem comprising silicon-micromachined first- and second-dimension separation columns and a silicon-micromachined thermal modulator (μTM) for comprehensive two-dimensional (i.e., μGC × μGC) separations are described. The first dimension consists of two series-coupled 3.1 cm × 3.1 cm μcolumn chips with etched channels 3 m long and 250 μm × 140 μm in cross section, wall-coated with a poly(dimethylsiloxane) (PDMS) stationary phase. The second dimension consists of a 1.2 cm × 1.2 cm μcolumn chip with an etched channel 0.5 m long and 46 μm × 150 μm in cross section wall-coated with either a trigonal tricationic room-temperature ionic liquid (RTIL) or a commercial poly(trifluoropropylmethyl siloxane) (OV-215) stationary phase. The two-stage, cryogen-free μTM consists of a Si chip containing two series-coupled, square spiral channels 4.2 cm and 2.8 cm long and 250 μm × 140 μm in cross section wall-coated with PDMS. Conventional injection methods and flame ionization detection were used. Temperature-ramped separations of a simple alkane mixture using the RTIL-coated second-dimension ((2)D) μcolumn produced reasonably good peak shapes and modulation numbers; however, strong retention of polar compounds on the RTIL-coated (2)D μcolumn led to excessively broad peaks with low (2)D resolution. Substituting OV-215 as the (2)D μcolumn stationary phase markedly improved the performance, and a structured 22 min chromatogram of a 36-component mixture spanning a vapor pressure range of 0.027 to 13 kPa was generated with modulated peak fwhm (full width at half-maximum) values ranging from 90 to 643 ms and modulation numbers of 1-6.
本文描述了一种微分析子系统的开发与特性，该子系统包括用于全二维（即μGC×μGC）分离的硅微机械加工的一维和二维分离柱以及硅微机械加工的热调制器（μTM）。一维由两个串联的3.1 cm×3.1 cm微柱芯片组成，蚀刻通道长3 m，横截面为250 μm×140 μm，壁涂有聚二甲基硅氧烷（PDMS）固定相。二维由一个1.2 cm×1.2 cm微柱芯片组成，蚀刻通道长0.5 m，横截面为46 μm×150 μm，壁涂有三角三阳离子室温离子液体（RTIL）或商用聚（三氟丙基甲基硅氧烷）（OV - 215）固定相。两级无低温致冷的μTM由一个硅芯片组成，该芯片包含两个串联的方形螺旋通道，长4.2 cm和2.8 cm，横截面为250 μm×140 μm，壁涂有PDMS。采用了传统的进样方法和火焰离子化检测。使用涂有RTIL的二维（(2)D）微柱对简单烷烃混合物进行程序升温分离，得到了相当好的峰形和调制数；然而，极性化合物在涂有RTIL的(2)D微柱上的强保留导致峰过宽，二维分辨率低。用OV - 215作为(2)D微柱固定相显著提高了性能，生成了一个36组分混合物的结构化22分钟色谱图，其蒸气压范围为0.027至13 kPa，调制峰半高宽（fwhm）值范围为90至643 ms，调制数为1 - 6。
