Cationic gemini surfactant-resorcinol-aldehyde resin and its application in the extraction of endocrine disrupting compounds from food contacting materials.

A new cationic gemini surfactant-resorcinol/formaldehyde resin was designed and synthesized. Cationic gemini surfactant was introduced into the resorcinol/formaldehyde resin for the first time and led to the retention of negatively charged endocrine disrupting compounds (EDCs) through electrostatic interactions, hydrogen bonding and π-π interactions. The synthesized material showed good performance in the dispersive micro-solid phase extraction (D-µ-SPE) of EDCs such as alkylphenol and phenoxy acid herbicides from food packaging migrants. Extraction parameters such as pH, adsorbent dose, extraction time and salting out effect were optimized. The limits of detections were in the range of 0.5-0.8 ng/mL, and the recoveries were in the range of 90-100%. The developed method was applied to the analysis of EDCs from food contacting materials migrants with pentachlorophenol, 2,4-dichlorophenoxyacetic acid and bisphenol A detected in the concentration range of 0.2-1.2 mg/kg. It also showed great potential in the D-µ-SPE of other compounds with negative charge or high hydrophobicity.

Quaternary ammonium-functionalized MCM-48 mesoporous silica as a sorbent for the dispersive solid-phase extraction of endocrine disrupting compounds in water.

MCM-48 mesoporous silica was functionalized with dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride, a quaternary ammonium salt with a long hydrophobic chain, to prepare a new sorbent for the dispersive solid-phase extraction (DSPE) of seven endocrine disrupting compounds (EDCs) including 4-hexylphenol, 4-octylphenol, 4-nonylphenol, bisphenol A, estrone, 17ß-estradiol and estriol in water. A series of differently functionalized MCM-48 materials were also synthesized, and they served as reference materials to study the mechanism. The developed DSPE method was combined with HPLC with fluorescence detection to evaluate the adsorption performance. The results indicated that the quaternary ammonium-functionalized MCM-48 mesoporous silica can be used as ideal sorbent for EDCs in water with recoveries of higher than 95% due to the electrostatic interactions and hydrophobic effect. Hydrogen bonding and π-π interactions in other synthesized materials could lead to about 25-30% increase in recoveries, but the results for polyhydroxy compounds were still not satisfying. The quaternary ammonium-functionalized MCM-48 mesoporous silica was successfully applied to the DSPE of EDCs in real water samples. The optimum extraction conditions were sorbent amount, 15 mg; desorption time; 5 min; elution volume, 0.8 mL; sample pH 3.0; and salt addition, 5 g/L. The limits of detection were in the range of 1.2-2.6 ng/L, while the limits of quantitation were in the range of 4.3-8.3 ng/L.