Miniaturized extraction methods of triclosan from aqueous and fish roe samples. Bioconcentration studies in zebrafish...

Triclosan, an antibacterial and antifungal agent, is widely used in household and personal care products, processed foods and food packaging, etc., and thus also released into the environment. Triclosan is acutely and chronically toxic to aquatic organisms and bioaccumulates in fish tissue. Here, we propose a new miniaturized triclosan extraction method for aqueous and fish roe samples, based on the use of a vortex mixer and an ultrasonic probe, respectively, and useful for triclosan determination by gas chromatography coupled to a micro electron capture detector. Different solvents for extraction and sorbents for clean-up purposes were tested. Multivariate optimization of the variables affecting ultrasonic extraction (ultrasound radiation amplitude, sonication time, sample temperature, and the ratio of sample amount and extracting volume) was carried out. Solvent extraction using ethyl acetate and further clean-up with mixed bed cartridges with two layers of Florisil® and Florisil® impregnated with 10% sulfuric acid only for fish roe samples was finally selected. Extraction efficiencies of up to 95% and 90%, and detection limits of 0.165 ng ml(-1) and 2.7 ng g(-1) for aqueous and fish roe samples were obtained, respectively. The optimized method was used in bioconcentration studies with zebrafish larvae (Danio rerio), as an alternative method to the Organization for Economic Cooperation and Development technical guideline 305. Bioconcentration values, BCF = 2,630 and 2,018 at exposure concentrations of 30 and 3 μg L(-1), respectively, were assessed. These results are in agreement with those reported in the literature, showing the feasibility of the method for estimation of toxicokinetic parameters and bioconcentration factors using zebrafish larvae instead of adult fishes, reducing considerable animal testing, as suggested by the European legislation.