Determination of carbonyl compounds in fish species samples with solid-phase microextraction with on-fibre derivatization

Headspace solid-phase microextraction (HS-SPME) with on-fibre derivatization has been applied for determining volatile carbonyl compounds in fish muscle samples associated to different species and technological treatments. o-2,3,4,5,6-(Pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) has been used as derivatization reagent and the formed oximes were determined by gas chromatography coupled to mass spectrometry (GC–MS). The method has been optimised for improving the extraction–derivatization of analytes. Factors as the type of fibre, salting-out effect, incubation temperature and time, stirring and sample volume have been evaluated. The technique combines the typical advantages of SPME (economical, solventless, minimal sample handling or suitability for routine analysis) with a very high sensitivity using low quantities of sample (only 0.5 g of muscle). The comparison with an optimised and validated SPME method without derivatization showed excellent results in terms of sensitivity and selectivity since several compounds, as those associated to technological processes were detected in the different fish samples only after carbonyl derivatization.