A novel porphyrin-based conjugated microporous nanomaterial for solid-phase microextraction of phthalate esters residues in children's food.

A novel porphyrin-based conjugated microporous polymer (PCMP) with microporous structure and nitrogen-rich pyrrole building blocks was synthesized. The PCMP was used as a coating material to prepare solid-phase microextraction (SPME) fibers by sol-gel technique. Due to the toxicity of the phthalate esters (PAEs) and the necessity for their sensitive determinations in some food samples, the SPME fiber was investigated for the extraction of eleven PAEs from six different children's milk beverages prior to their detection by gas chromatography-mass spectrometry. Under the optimal conditions, the linear response range for the PAEs was in the range from 0.03 to 200 µg L-1 and the limits of detection (S/N = 3) for the analytes were 0.01-3.00 µg L-1. The method recoveries for the PAEs were between 80% and 120%, with the relative standard deviations varying from 1.3% to 9.8%. The method was successfully applied for the determination of PAEs in children's milk beverages.

Efficient solid-phase microextraction of twelve halogens-containing environmental hormones from fruits and vegetables by triazine-based conjugated microporous polymer coating.

A triazine-based conjugated microporous polymer (TCMP) was generated by introduced 1, 3, 5-triazine into conjugated microporous polymer network via Friedel-Crafts reaction. Under the optimum synthesis conditions, the obtained TCMP has a loose and porous structure. It was then used as a fiber coating material for solid-phase microextraction (SPME) of halogens-containing environmental hormones. It showed a strong adsorption capability due to the halogen bond, electrostatic, π-π stacking and hydrophobicity interactions. An analytical method combining the TCMP coated fiber-based SPME with gas chromatography-electron capture detection was developed to determine twelve halogens-containing environmental hormones in vegetable and fruit samples. A wide linear range (0.07-100.0 ng g-1) with the determination coefficients in the range of 0.9907-0.9996 and low limits of detection (0.02-0.04 ng g-1, S/N = 3) were achieved under optimized experimental conditions. The applicability of the established method was evaluated by the determination of the environmental hormones from three different fruit samples (apple, nectarine and pear) and five vegetable samples (Chinese cabbage, pakchoi, baby cabbage, rape and round lettuce). The resulting relative recoveries ranged from 76.6% to 123% with the relative standard deviations less than 10%. This research demonstrates the application potential of the TCMP coated fiber in the analysis of the halogens-containing environmental hormones in real vegetable and fruit samples.

Preparation of phenylboronic acid based hypercrosslinked polymers for effective adsorption of chlorophenols.

Hypercrosslinked polymers (HCPs) have demonstrated effective adsorption capabilities because of their rich porosity and high specific surface area. However, the HCPs prepared with phenylboronic acid based compounds as monomers via Friedel-Crafts alkylation reaction have not been reported yet. Herein, four new HCPs with phenylboronic acid (PBA), 1,4-benzenediboronic acid, 4-hydroxyphenylboronic acid and 4-carboxyphenylboronic acid as the respective monomers were prepared for the first time. Their Brunner-Emmet-Teller surface areas were 909.1 m2 g-1, 71.9 m2 g-1, 39.8 m2 g-1 and 29.3 m2 g-1, respectively. The prepared HCP with PBA as the monomer (named as PBA-HCP) displayed the best adsorption capability for chlorophenols. Then, it was investigated as a SPE adsorbent for the extraction of some chlorophenols from water and honey-pomelo beverage samples prior to high performance liquid-phase chromatography with diode array detection. The established method had low limits of detection for the analytes in the range from 0.06 to 0.2 ng mL-1 for water samples and from 0.3 to 1.0 ng mL-1 for honey-pomelo beverage samples. The linear response for the analytes was in the range of 0.18-100.0 ng mL-1 for water samples and 0.9-100.0 ng mL-1 for honey-pomelo beverage samples. The method also had a good repeatability with the relative standard deviations less than 7.1% and a fairly good accuracy with the method recoveries falling between 80.0% and 120.0%. The adsorption capacities of the PBA-HCP for 2-chlorophenol, 3-chlorophenol, 2,3-dichlorophenol and 2,4-dichlorophenol were 21.7 mg g-1, 31.2 mg g-1, 77.1 mg g-1 and 82.1 mg g-1, respectively. The PBA-HCP also exhibited excellent extraction capabilities for some other compounds, especially for those that have more hydrogen bonding sites.