Determination of selected volatile terpenes in fish samples via solid phase microextraction arrow coupled with GC-MS.

ABSTRACT

A high-efficiency enrichment method is required for determination of trace-level volatile terpenes in fish tissue, since the presence of such compounds in fish at elevated levels may induce bad sensory acceptance of fish meat, thus degrading its customer acceptance and consequently, its market value. In this study, a solid-phase microextraction (SPME) arrow configuration using a thick sorbent coating (120 µm, PDMS/CWR) was applied to enrich selected terpenes, namely α-pinene, limonene, linalool, and citronellol, in fish tissue (Oreochromis niloticus). Due to the thicker coating of the SPME arrow, a longer extraction time of 60 min was required to reach equilibrium extraction in comparison to the traditional fiber configuration. SPME conditions such as extraction temperature (60 °C), desorption temperature (250 °C), and salt effect (10% NaCl) were optimized for the developed application using the arrow configuration. The developed method exhibited good linearity at a concentration range of 5.0-500.0 µg L-1 for α-pinene and limonene, and 50.0-500.0 µg L-1 for linalool and citronellol. In addition, the coefficients of determination (R2) for all terpenes ranged from 0.9990 to 0.9999. The developed method was shown to be robust with good inter-day reproducibility in the range of 3.6-8.3%. Method sensitivity was assessed in terms of limits of detection (LODs) and limits of quantification (LOQs), with higher sensitivity achieved for α-pinene and limonene (LODs of 1.7 µg L-1) in comparison to linalool (LOD, 5.0 µg L-1) and citronellol (LOD, 17.0 µg L-1). Theoretical calculations verified that the increased coating thickness afforded by the arrow configuration can enable higher method sensitivity and widen the range of detected compounds for the headspace SPME.