Evaluation of Comprehensive 2D Gas Chromatography-Time-of-Flight Mass Spectrometry for 209 Chlorinated Biphenyl Congeners in Two Chromatographic Runs
Figure 2
Use of chromatographic and mass spectrometric data in a case of isomer coelution. (a) Contour plot from above looking down on a 2D run of the coeluting 2,2′- and 2,6-dichlorobiphenyls. (b) Chromatogram of the overlapping isomers viewed from the side and showing three slices each, taken from the 2D mode of separation. (c) The mass spectra obtained from pure standards of the individual isomers, each with two ortho chlorines, but one having these chlorines on separate rings (2,2′-) and showing the mass spectrometric “ortho effect.” (d) Mass chromatograms of the isomer mixture showing m/z 222 (blue), m/z 187 (green), and m/z 152 (red) and the partial resolution and assignment of the isomers based on these relative intensities.
