Determination of polybrominated diphenyl ethers in milk samples. Development of green extraction coupled techniques for sample preparation

BERTON, PAULA; MAMMANA, SABRINA B.; LOCATELLI, DANIELA; LANA, NERINA B.; HAPON, MARÍA B.; CAMARGO, ALEJANDRA B.; ALTAMIRANO, JORGELINA C.

ELECTROPHORESIS

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2017

0173-0835

Ultrasound-assisted extraction (UAE), cloud point extraction (CPE) and ultrasound back-extraction (UABE) techniques have been coupled for extraction, preconcentration, and cleanup of polybrominated diphenyl ethers (PBDEs) from milk samples and further determination by gas chromatography with electron capture detector (GC-ECD). Physicochemical parameters that affect the efficiency of the extraction system were investigated considering the sample matrix by using a design of experiments based on statistical tools. Initially, factorial designs were used for selecting the variables that condition the extraction system. Those variables that showed significant effects on the analytical responses were considered within a further central composite design (CCD) study. The investigated and optimization assays lead to the following analytical methodology: UAE for lixiviation of PBDEs from milk sample was carried out using 3 mL acetone:hexane solution (30:70). After lixiviation (2 cycles of 25 min each), the solvent phase was evaporated and analytes were extracted from the remaining aqueous phase. For cloud point extraction 0.5 mL Triton X-114 1% w/v and 0.56 mL 4% w/v NaCl were added to the tube and stirred by using a vortex. The extraction system was kept at 55 °C for 10 min to induce the cloud point of the surfactant and further centrifugated for phases separation. After discarding the aqueous phase, a back-extraction assisted with ultrasound was later used to recover the analytes from coacervate phase into isooctane (90 µL) at 40°C for 3 min, which was later injected into a GC-ECD for analysis. Under optimum conditions, the proposed methodology exhibits good performance in terms of linearity and precision, with recoveries in the range of 83-94% and limits of detection (LODs) within the range 0.05 ? 0.5 ng g-1 dry weight (d.w.). The optimized methodology was used for the determination of PBDEs in powder milk samples, both types of commercial and human sources. The proposed methodology constitutes a suitable approach for the analysis of target compounds in complex biological samples and requires minimum organic solvents consumption.