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Determination of endocrine disruptors in honey by CZE-MS using restricted access materials for matrix cleanup

Rodríguez-Gonzalo, Encarnación, Domínguez-Álvarez, Javier, García-Gómez, Diego, García-Jiménez, María-Guadalupe, Carabias-Martínez, Rita
Electrophoresis 2010 v.31 no.13 pp. 2279-2288
2,4,5-trichlorophenol, 2,4-dichlorophenol, ammonia, bisphenol A, drying, electrophoresis, electrospray ionization mass spectrometry, endocrine-disrupting chemicals, experimental design, honey, methanol, pentachlorophenol, solvents, temperature
An analytical method based on CZE coupled to ESI-MS is proposed for the identification and simultaneous quantification of several endocrine-disrupting chemicals in honey. The target compounds were the chlorophenols: 2,4-dichlorophenol, 2,4,5-trichlorophenol and pentachlorophenol, and bisphenol-A, 4-tert-butylphenol, and 4-tert-butylbenzoic acid. A two-step optimization of the ESI-MS detection was carried out. First, the organic solvent present in the sheath liquid was selected and its effect on the analytical signal was studied. The best results in terms of the intensity of the MS signals were obtained with methanol. Thus, an experimental design technique (Doehlert type) was used for the optimization of the other parameters: the NH₃ concentration in the sheath liquid, the flow of the sheath liquid, the nebulizer pressure in ESI, and the drying gas temperature and flow. Here, we developed a new sample treatment based on the combined use of a restricted access material and a polymeric sorbent for SPE. The LOD achieved were in the range of 5-31 ng/g. The intraday precision of the proposed method was determined from replicate analyses (n=4) at a concentration level of 50 ng/g, with RSD values in the range of 15-23%. The results revealed that the proposed method is suitable for the reliable quantification of endocrine-disrupting chemicals in honey at nanograms per gram levels.