Comprehensive two-dimensional gas chromatography of complex samples by using a 'reversed-type' column combination: application to food analysis.

The practicability and potential of a non-orthogonal approach in comprehensive two-dimensional gas chromatography (GC x GC) were studied and compared to those of the orthogonal approach for two different complex matrices, and using conventional flame ionisation (FID) and time-of-flight mass spectrometry (ToF MS) detection. The separation of a diesel oil showed that the non-orthogonal approach also provides interesting, but completely reversed, ordered structures. For the more extensively studied flavour analysis in food samples, improved peak shapes and, also, different types of ordered structures and retention behaviour, and improved detectability for polar compounds make the two approaches complementary to each other. As a consequence, identification and/or determination of targets and/or unknowns can be performed more reliably. Analytical performance (close to three-order linearity; LODs, 2-30 pg injected in most cases; R.S.D.s, 1-6% (n = 6)) was fully satisfactory.