[Determination of four phenolic endocrine-disrupting chemicals in water by dispersive solid-phase extraction-ultra performance liquid chromatography-tandem mass spectrometry based on metal-organic skeleton porous carbon materials].

Phenolic endocrine-disrupting chemicals (EDCs) are exogenous substances that interfere with the endocrine system and disrupt normal cell functions upon entering a living organism, leading to reproductive and developmental toxicity. Therefore, the development of a rapid and efficient analytical method for detecting phenolic EDCs in environmental waters is crucial. Owing to the low concentration of phenolic EDCs in environmental water, appropriate sample pretreatment methods are necessary to remove interferences caused by the sample matrix and enrich the target analytes before instrumental analysis. Dispersive solid-phase extraction (DSPE) has gained considerable attention as a simple and rapid sample pretreatment method for environmental-sample analysis. In this method, an adsorbent material is uniformly dispersed in a sample solution and the target analytes are extracted through processes such as vortexing. Compared with traditional solid-phase extraction (SPE), DSPE increases the contact area between the adsorbent and sample solution, reduces the required amounts of adsorbent and organic solvents, and improves the extraction efficiency. The adsorbent material plays a critical role in DSPE because it determines the extraction efficiency of the method. Metal-organic frameworks (MOFs) are porous framework materials composed of metal clusters and multifunctional organic ligands. They possess many excellent properties such as tunable pore sizes, large surface areas, and good thermal and chemical stability, rendering them ideal adsorbent materials for sample pretreatment. MOF-derived porous carbon materials obtained through high-temperature carbonization not only increase the density of MOF materials for better separation but also retain the advantages of a large surface area, highly ordered porous structure, and high porosity. In this study, a porous carbon material derived from an MOF, named as University of Oslo-66-carbon (UiO-66-C), was synthesized using a solvothermal method and applied as an adsorbent to enrich four phenolic EDCs (bisphenol A, 4-tert-octylphenol, 4-nonylphenol, and nonylphenol) in water. A method combining DSPE with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established to analyze these phenolic EDCs in water. The UiO-66-C dosage, pH of water sample, adsorption time, eluent type and volume, elution time, and ion strength were optimized. Gradient elution was performed using methanol-water as the mobile phase. The target analytes were separated on an ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 µm), and multiple reaction monitoring (MRM) was conducted in negative electrospray ionization mode. The method exhibited a linear correlation within the range of 0.5-100 µg/L for the four phenolic EDCs. The limits of detection (LODs) and quantification (LOQs) of the four phenolic EDCs were 0.01-0.13 µg/L and 0.03-0.42 µg/L, respectively. The precision of the method was evaluated through intra- and inter-day relative standard deviations (RSDs), with values ranging from 1.5% to 10.6% and from 6.1% to 13.2%, respectively. When applied to the detection of phenolic EDCs in tap and surface water, the spiked recoveries of the four phenolic EDCs were 77.1%-116.6%. Trace levels of 4-nonylphenol and nonylphenol were detected in surface water at levels of 1.38 and 0.26 µg/L, respectively. The proposed method exhibits good accuracy and precision; thus, it provides a new rapid, efficient, and sensitive approach for the detection of phenolic EDCs in environmental water.

Isolation and characterization of an abamectin-degrading Burkholderia cepacia-like GB-01 strain.

Abamectin is widely used in agriculture as an insecticide and in veterinary as an anti-parasitic agent, and has caused great environmental pollution by posing potential risk to non-target soil invertebrates and nearby aquatic systems. A bacterium designated GB-01, which was capable of degrading abamectin, was isolated from soil by enrichment culture method. On the basis of morphological, physiological and biochemical characteristics, combined with phylogenetic analysis of 16S rRNA gene, the bacterium GB-01 was identified as Burkholderia cepacia-like species. The bacterium GB-01 was able to utilize abamectin as its sole carbon source for growth, and could degrade more than 90% of abamectin at initial concentrations of 50 and 100 mg l(-1) in mineral salt medium in 30 and 36 h, respectively. The longer degradation cycle was observed with abamectin concentrations higher than 100 mg l(-1). Optimal growth temperatures and pH values with highest degradation rate were 30-35 degrees C and 7-8, respectively. Two new degradation products were identified and characterized by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) based mass spectral data and a plausible partial degradation pathway of abamectin was proposed. This is the first report in which an abamectin-degrading Burkholderia species isolated from soil was identified and characterized.

Biodegradation of the sulfonylurea herbicide chlorimuron-ethyl by the strain Pseudomonas sp. LW3.

The chlorimuron-ethyl-degrading bacterium LW3 was isolated from contaminated soil and identified by 16S rRNA gene sequencing as Pseudomonas sp. When chlorimuron-ethyl was provided as the sole nitrogen source, the degradation efficiency in liquid medium was about 81.0% after 7 days of inoculation with strain LW3. The effects of chlorimuron-ethyl concentration and temperature on biodegradation were examined. Two metabolites of degradation were analyzed by LC/MS. Based on the identified products, strain LW3 seemed to be able to degrade chlorimuron-ethyl by cleavage of the sulfonylurea bridge. The inoculation of strain LW3 to chlorimuron-ethyl-treated soil resulted in a higher degradation rate than in uninoculated soil, regardless of the soil being sterilized or nonsterilized. This microbial culture has great potential for the bioremediation of soil contaminated with chlorimuron-ethyl.

[Isolation of a monocrotophos-degrading bacterial strain and characterization of enzymatic degradation].

A monocrotophos [dimethyl (E)-1-2-methylcarbamoylvinylphosphate or MCP] -degrading strain named as M-1 was isolated from sludge collected from the wastewater treatment pool of a pesticide factory and identified as Paracoccus sp. according to its morphology and biochemical properties and 16S rDNA sequence analysis. Using MCP as a sole carbon source, M-1 was able to degrade MCP(100 mg x L(-1)) by 92.47% in 24 h. The key enzyme(s) involved in the initial biodegradation of monocrotophos in M-1 was shown to be constitutively expressed cytosolic proteins and showed the greatest activity at pH 8.0 and 25 degrees C, with its Michaelis-Mentn's constant (K(m)) and maximum degradation rate (V(max)) of 0.29 micromol x mL(-1) and 682.12 micromol (min x mg)(-1) respectively. This degrading enzyme(s) was sensitive to high temperature, but kept high activity under alkaline conditions.

[Determination of alkaloids from Coptis chinensis Franch. and Phellodendron amurense Rupr. Decocted together in baitouweng decocta by high performance capillary electrophoresis].

A rapid and accurate method for determining alkaloids from Coptis chinensis Franch, and Phellodendron amurense Rupr, decocted together in Baitouweng decocta was established. Experiments were carried out on a self-assembled capillary electrophoresis system. The experimental conditions were as follows: 75 microns i.d. x 50 cm fused silica capillary, 0.05 mol/L Na2B4O7-CH3OH (85:15, V/V) as buffer, applied voltage 14 kV and detection wavelength 232 nm. In addition, the concentration of ethanol in the extraction solvent was optimized. Experimental results showed that ethanol-water (30:70, V/V) was the ideal solvent to extract the main effective ingredients from Coptis chinensis Franch. and Phellodendron amurense Rupr. decocted together in Baitouweng decocta. Berberine and palmatine had good linearities in the range of 15.0 mg/L-65.0 mg/L and 12.5 mg/L-50.0 mg/L respectively, and their average recoveries were 95.5%-104% (RSD 2.7%-6.9%) and 92.1%-103% (RSD 4.5%-6.7%) respectively.

[New technologies of solid-phase microextraction].

Solid-phase microextraction (SPME) is a technology with functions of sampling, extraction and concentration based on adsorption/absorption-desorption equilibrium between coating and sample. The recent development of SPME is reviewed. Studies on the in-tube-SPME technology, novel extraction probes and its coupling with other analytical technologies are summarized.