In-port derivatization after sorptive extractions

Derivatization is necessary when analysis of polar compounds containing hydroxyl, carboxylic acid, amine or thiol functional groups is accomplished by gas chromatography (GC), in order to improve peak symmetry, peak separation and detector response. Derivatization can be performed off-line in a reaction vessel that is separated from the GC analysis hardware. However, on-line derivatization can eliminate time-consuming sample-processing steps, decrease the amount of valuable and/or toxic reagents and solvents that are used off-line, as well as increase the speed and efficiency of the analysis performed. The present work revises on-line in-port derivatizations where the derivatization reaction is simultaneously carried out with the analysis step by injecting the sample/reagent mixture directly into the hot GC inlet after a sorptive extraction step. Sorptive extractions revised range from the more classical solid-phase extraction (SPE) to the microextraction approaches, including solid-phase microextraction (SPME) and stir-bar sorptive extraction (SBSE) applications, as well as liquid-phase microextraction (LPME) or microextraction by packed sorbent (MEPS).