Micellar organized medium as extraction and preconcentration technique for GC-MS: determination of brominated flame retardants in water samples

FONTANA, ARIEL R.; SILVA, MARIA F.; DE SOUZA DIAS, FABIO; WUILLOUD, RODOLFO G.; MARTINEZ, LUIS D.; ALTAMIRANO, JORGELINA C.

Florianopolis, Santa Catarina, Brasil

Congreso; CONGRESSO LATINO AMERICANO DE CROMATOGRAFIA E TECNICAS RELACIONADAS; 2008

A novel and efficient analytical methodology is proposed for extracting and preconcentrating polybrominated diphenyl ethers (PBDEs) from water samples prior gas chromatography-mass spectrometry (GC-MS) analysis. PBDEs are a group of environmental persistent pollutants, which are related to health risks such as endocrine disruption, adverse neurobehavioral effects and probable carcinogens. The proposed methodology is based on the induction of micellar organized mediums by using a non-ionic surfactant (Triton X-114) to extract the target PBDEs. Due to the high viscosity of the surfactant phase, it is not possible to inject it into the GC column; therefore an ultrasound back-extraction into an organic solvent (isooctane) was applied in order to enable the efficient coupling of the extracting technique with GC-analysis. Several factors including surfactant type and concentration, equilibration temperature and time, ionic strength, etc., were studied and optimized over the extraction efficiency of the proposed technique. Under the optimum back extraction conditions, there was no interference or blocking of the column. Under optimum experimental conditions, the target analytes were quantitatively extracted achieving an enrichment factor of 200 when 10 mL of 10 pg mL-1 PBDEs mix was extracted. Detection limits calculated as three times the signal-to-noise ratio (S/N), ranged from 0.8 to 2 pg mL-1 and the RSD were higher than 7.2 % (n = 5) when 10 pg mL-1 PBDEs water solution was analyzed. The calibration curves obtained following the proposed methodology have a linear range between 4.1 and 500 pg mL-1 for each PBDEs and the correlation coefficients were  higher than 0.9987. The proposed methodology was then applied for the analysis of PBDEs (BDE-47, -99, -100 and -153) in water samples including drinking, lake and river waters. Although significant quantities of PBDEs weren?t found in the analyzed samples, the proposed methodology was validated by performing a recovery study spiking the samples at two different concentration levels of PBDEs (10 and 50 pg mL-1). Recoveries values in the range of 96-106% were obtained showing a successful robustness of the method for analyzing PBDEs in water samples.