13.2: Advances in GC
- Page ID
- 220491
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Multidimensional Gas Chromatography (GC-GC, 2D-GC)
Recently the idea of multidimensional gas chromatography separations has be proven to be very useful for closely eluting solutes in experiments with a single column. (see Liu and Phillips, Journal of Chromatographic Science. 29 (6), 227–231, 1991). Multidimensional GC is based upon sending groups of closely eluting solutes (on a long column of one selectivity onto a second shorter column of a different selectivity). As shown in Figure\(\PageIndex{1}\) a fast value is used to the red and blue co-eluting in Column 1 solutes onto Column 2 where are being further separated they are better separated.
Figure\(\PageIndex{1}\) : A schematic diagram of a two dimension GC instrument. Image source currently unknow.
An example of the utility of multidimensional GC is shown in Figure\(\PageIndex{2}\) - Figure\(\PageIndex{4}\). Figure\(\PageIndex{2}\) depicts a typical one dimensional GC separation of a large number of polycyclic aromatic compounds on an appropriate coluum. Despite the 40 m length of the capillary column, there are numerous examples of co-eluting solutes presented in the focus boxes.
Figure\(\PageIndex{2}\) : The gas chromatograph for a large series of polycyclic aromoatic solutes on a 40 M RXi-PAH column. Imge source currently unknown
Figure\(\PageIndex{3}\) reveals the 2D chromatogram when the solutes eluting through the RXi-PAH column arriving between approximately 15 and 24 min in Figure\(\PageIndex{1}\) are directed onto a short, 1 M, RXi-1HT column for separation on a column with a different selectivity. (Note an even longer RXi-PAH column, 60 M, was used in the the 2D GC instrument)
Figure\(\PageIndex{3}\): A focused region in the 2D - GC experiment of the solutes eluting from approximately 15 min to 24 min in Figure 12.2.2. Image source currently unknown.
Figure\(\PageIndex{4}\) is a zoom of the region in Figure 12.2.3 corresponding to the box centered at 16 min in Figure\(\PageIndex{2}\) and containing the signals for benz[a]anthracene, chrysene, triphenylene and cyclopenta[cd]pyrene revealing the full resolution for the separation of these solutes.
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Figure\(\PageIndex{4}\) : A focused region in the 2D - GC experiment revealing the full resolution of the following solutes: benz[a]anthracene, chrysene, triphenylene and cyclopenta[cd]pyrene. Image source currently unknown.