Coupling strategies for planar solid phase extraction with gas chromatography using the example of mineral oil saturated and aromatic hydrocarbons (MOSH and MOAH)

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The fundamental techniques for the coupling of planar solid phase extraction (pSPE) with gas chromatography (GC) should be developed. The basics for the pSPE-GC coupling are studied using the challenging trace analysis of saturated and aromatic mineral oil hydrocarbons (MOSH and MOAH) in packaging materials and dry, low-fat foodstuffs. Two different coupling techniques are to be developed and optimized. On the one hand, pSPE is coupled to GC by liquid injection after the elution of the target analytes from the thin-layer plate, and on the other hand, the direct, non-discriminatory and loss-free coupling by thermal desorption is to be investigated. For both strategies, the versatile and cost-effective pSPE is used for the pre-separation of the MOSH and MOAH fractions and replaces the currently used LC or SPE pre-separation. By the coupling of pSPE to GC, the accessible analyte range for pSPE which actually is limited to LC-amenable analytes, is considerably expanded. Using the developed pSPE-GC coupling techniques, the effective pSPE concept will not only be applicable for the MOSH/MOAH substance classes, but will also allow the efficient, reliable and highly selective analysis for a wide range of GC-amenable substances, with the exact quantitation down to trace levels. A further objective is to develop the pSPE, coupled to spectroscopic detection (UV/FLD), as a fast screening tool for the reliable quantitation of MOSH and MOAH in food packaging materials, cosmetics, and dry, low-fat foods for many samples in parallel directly on the thin-layer plate. Finally, the developed techniques for pSPE, UV/FLD and GC-FID are combined to offer an efficient, modular designed overall analysis strategy, which can be used for the entire field of MOSH/MOAH analysis and can easily be adapted to further GC-amenable substance classes. The developed pSPE-UV/FLD-GC-FID strategy is tested for its suitability and trueness by comparing the results with data obtained by the currently used on-line LC-GC-FID method.