Selective Extraction of Trace Levels of Polychlorinated and Polybrominated Contaminants by Supercritical Fluid-Solid-Phase Microextraction and Determination by Gas Chromatography/Mass Spectrometry. Application to Aquaculture Fish Feed and Cultured Marine Species

Abstract

The persistence, ubiquity, and toxicity of polyhalogenated compounds, together with their presence in fish feed, make it necessary to monitor these organic pollutants in the routine quality assurance programs of aquaculture activities, as this food chain is a source of these toxic compounds for human consumers. A new approach based on simultaneous supercritical fluid extraction-sample cleanup, followed by solid-phase microextraction-gas chromatography/mass spectrometry (SFE-SPME-GC/MS/MS) has been developed as an advantageous analytical tool for the determination of 15 organohalogenated compounds (including pesticides, polychlorinated and polybrominated biphenyls, and polybrominated diphenyl ethers) in aquaculture feed at very low levels. The influence of several parameters in the efficiency of the SPE/SPME combination was systematically investigated by chemometric approaches. In the optimal conditions, the developed procedure provides an excellent linearity, detection, and quantification limits (below 10 pg/g) for most of the analytes investigated, being at the same time advantageous in terms of rapidity, convenience, and avoiding the need of toxic organic solvents. The procedure was applied to the analysis of aquaculture feed and cultured marine species and tested for accuracy against IAEA 406 reference material.

Supercritical fluid extraction of polyhalogenated pollutants from aquaculture and marine environmental samples: A review

“…The impact of pressure on recovery appears to be very important, with recoveries increasing as the pressure rises in a wide range of working pressures (16 -43 MPa) depending on the behaviour of different groups of pollutants [41, 48, 53 -56]. In these cases, temperature has a slight negative effect, which is not significant, so it would be advisable to set this parameter at a low level [48,53,55,57]. High temperatures (between 35 and 858C) and fluid densities were shown to benefit the extraction efficiency probably due to a simpler process of desorption of the semivolatile analytes from the active sites on the matrix and better solubilisation in the supercritical fluid [27,58].…”

“…Moreover, the static extraction time exhibits a weak negative effect, hence its value should be set at a low level (5 -10 min) [48,49,53,55,56]. In keeping with this, a short dynamic extraction time (10 -30 min) may also be selected, largely benefiting the throughput, while also avoiding analyte degradation [53 -56, 62].…”

“…A good way to establish practical compromise settings for simultaneous multiresidue extraction conditions is to implement a multicriteria decision-making procedure using desirability function optimisation [44,55,56].…”

“…Quantitative recoveries were obtained from two different certified reference materials (CRMs; RM IAEA 406 and WMF-01) with low RSD% values (less than 14% in all cases). The same authors [55] improved the analytical procedure described above by including a solid-phase microextraction (SPME) step after the supercritical extraction for the determination of the same organohalogenated pollutants from fish feed and cultured marine species. This methodology offers the efficiency, rapidness and selectivity of SFE combined with the increased sensitivity provided by the SPME.…”

“…Another approach, SPME, has been used as an additional procedure for the clean-up and concentration of organohalogenated compounds from aquaculture feed and biological solid samples, after previous extraction using SFE [55]. The combination of the clean-up processes in the SFE cell with the subsequent SPME has resulted in a high degree of sensitivity and selectivity in the identification of pesticides, polyhalogenated and PBBs and polybrominated diphenyl ethers, reaching quantification limits on the order of pg/g.…”