Watson Nathanial E, Siegler W Christopher, Hoggard Jamin C, Synovec Robert E
Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195, USA.
Anal Chem. 2007 Nov 1;79(21):8270-80. doi: 10.1021/ac070829x. Epub 2007 Sep 27.
Development of a comprehensive, three-dimensional gas chromatograph (GC3) instrument is described. The instrument utilizes two six-port diaphragm valves as the interfaces between three, in-series capillary columns housed in a standard Agilent 6890 gas chromatograph fitted with a high data acquisition rate flame ionization detector. The modulation periods for sampling column one by column two and column two by column three are set so that a minimum of three slices (more commonly four or five) are acquired by the subsequent dimension resulting in both comprehensive and quantitative data. A 26-component test mixture and quantitative standards are analyzed using the GC3 instrument. A useful methodology for three-dimensional (3D) data analysis is evaluated, based on the chemometric technique parallel factor analysis (PARAFAC). Since the GC3 instrument produces trilinear data, we are able to use this powerful chemometric technique, which is better known for the analysis of two-dimensional (2D) separations with multichannel detection (e.g., GC x GC-TOFMS) or multiple samples (or replicates) of 2D data. Using PARAFAC, we mathematically separate (deconvolute) the 3D data "volume" for overlapped analytes (i.e., ellipsoids), provided there is sufficient chromatographic resolution in each of the three separation dimensions. Additionally, PARAFAC is applied to quantify analyte standards. For the quantitative analysis, it is demonstrated that PARAFAC may provide a 10-fold improvement in the signal-to-noise ratio relative to a traditional integration method applied to the raw, baseline-corrected data. The GC3 instrument obtains a 3D peak capacity of 3500 at a chromatographic resolution of one in each separation dimension. Furthermore, PARAFAC deconvolution provides a considerable enhancement in the effective 3D peak capacity.
本文描述了一种综合三维气相色谱仪（GC3）的开发。该仪器使用两个六通隔膜阀作为接口，连接安装在配备高数据采集速率火焰离子化检测器的标准安捷伦6890气相色谱仪中的三根串联毛细管柱。设置第一根柱子对第二根柱子以及第二根柱子对第三根柱子的采样调制周期，以便后续维度至少采集三个切片（通常为四个或五个），从而获得全面且定量的数据。使用GC3仪器分析了一种26组分的测试混合物和定量标准品。基于化学计量学技术平行因子分析（PARAFAC），评估了一种用于三维（3D）数据分析的有用方法。由于GC3仪器产生三线性数据，我们能够使用这种强大的化学计量学技术，该技术在分析具有多通道检测的二维（2D）分离（例如GC×GC - TOFMS）或2D数据的多个样品（或重复样品）方面更为人所知。使用PARAFAC，我们在数学上分离（去卷积）重叠分析物（即椭球体）的3D数据“体积”，前提是在三个分离维度中的每一个维度都有足够的色谱分辨率。此外，PARAFAC用于定量分析物标准品。对于定量分析，结果表明PARAFAC相对于应用于原始基线校正数据的传统积分方法，可将信噪比提高10倍。GC3仪器在每个分离维度的色谱分辨率为1时，获得了3500的3D峰容量。此外，PARAFAC去卷积在有效3D峰容量方面提供了显著增强。
