In this work, an in situ acylation combined with solid-phase microextraction coupled to gas chromatography and mass spectrometry method has been developed for simultaneously determining haloanisoles (2,4,6-trichloranisole, 2,4,6-tribromoanisole), and their direct precursors (2,4,6-trichlorophenol, 2,4,6-tribromophenol) and indirect precursors (2-chloropenol, 2,4-dichlorophenol, 2-bromophenol, 2,4-dibromophenol) in water. The key parameters for the solid-phase microextraction were determined by using Plackett–Burman screening and optimized by central composite optimization. Under optimal conditions, the eight compounds can be analyzed in a short time (33 min) with a strong linearity ranging from 2 to 200 ng/L (correlation coefficient greater than 0.996), showing good sensitivities with the limit of detection in a range of 0.23–0.91 ng/L and a limit of quantification of 0.77–3.03 ng/L, good repeatability (2.00–9.10%) and interday precision (1.67–11.3%). When environmental water samples were treated, the recoveries of target compounds were 75.5–127.3%, suggesting that the developed method could be applied in probing the origin of haloanisoles and monitoring halophenols and haloanisoles in natural waters at concentration levels of ng/L.

•rGO/Fe3O4 was synthesized and firstly used as an adsorbent for 17α-ethinylestradiol.•The adsorption is spontaneous and endothermic with relatively high removal efficiency.•rGO/Fe3O4 could be recycled with simple magnetic separation.•The influence of a range of water chemistry parameters was investigated.A reduced graphene oxide (rGO) magnetic nanocomposite rGO/Fe3O4 was prepared and used to adsorb 17α-ethinylestradiol from aqueous solutions. The magnetic nanocomposite was characterized using X-ray powder diffraction, Raman spectroscopy, vibrating sample magnetometer measurements, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. It was shown that the Fe3O4 nanoparticles are uniformly deposited on the rGO sheets. Experiments were performed to elucidate the mechanism by which 17α-ethinylestradiol adsorbs onto rGO/Fe3O4. The kinetic adsorption data for 17α-ethinylestradiol fitted well with a pseudo-second-order model, while the equilibrium data followed Langmuir isotherms. Thermodynamic analysis indicated that the adsorption is a spontaneous and endothermic process. The effects of water chemistry (pH, coexisting ions, humic acid level, and water matrix) on 17α-ethinylestradiol adsorption were also investigated. It was found that pH and humic acid level have noticeable effects on the adsorption of 17α-ethinylestradiol, while coexisting ions and water matrix do not. Desorption experiments performed using methanol as eluent demonstrated that the adsorbent could be reused for five cycles without significant deterioration in performance. The results show that rGO/Fe3O4 exhibits high adsorption capacity and may be conveniently recovered, making it a promising adsorbent for 17α-ethinylestradiol removal from real-world water resources.Download high-res image (101KB)Download full-size image

•Research on the ozonization of IPMP and IBMP at ng L−1 level initial concentration was performed.•The intermediate by-products of IPMP and IBMP by ozonization were determined and characterized.•The possible degradation pathway of IPMP and IBMP by ozonization was for the first time proposed.2-isopropyl-3-methoxypyrazine (IPMP) and 2-isobutyl-3-methoxypyrazine (IBMP) are two of main taste and odor compounds in drinking water. The removal efficiency and possible degradation pathway of IPMP and IBMP by ozonization were studied by evaluating experimental parameters including ozonization time, initial concentration of IPMP and IBMP, and solution pH. At pH 6.8 the removal efficiency of IPMP and IBMP (100 ng L−1) were both found over 90% within 15 min ozonization, and a higher pH value (8.6) helped to accelerate the degradation in some degree. In both neutral and acidic media, the degradation followed the pseudo first order kinetics. In contrast, at lower pH range, e.g. pH 5.0, more than 10% of the title compounds were still existing even after 30 min ozonization. With increasing the initial concentration from 100 to 200 and to 400 ng L−1, the removal efficiency of the title compounds was decreased successively. The intermediate by-products of IPMP and IBMP by ozonization were mainly acid esters and carboxylic acids as identified by GC–MS, and accordingly the possible degradation pathway was proposed.

Lonicera caerulea L. fruit is an excellent source of bioactive compounds. An efficient separation method of cyanins is important for the development of many value-added products and functional food ingredients. High-speed counter-current chromatography (HSCCC) was applied to isolate cyanins from Lonicera caerulea fruits with a biphasic solvent system composed of methyl tert-butyl ether/n-butanol/acetonitrile/water/trifluoroacetic acid (2:2:1:5:0.01, volume ratio). 1.41 mg of cyanidin 3, 5-O-diglucoside, 1.08 mg of cyanidin 3-O-rutinoside and 6.38 mg of cyanidin 3-O-glucoside were obtained from 40 mg of crude extract. The purities of these compounds were 95.8%, 92.4% and 97.6%, respectively, as identified by high-performance liquid chromatography–diode array detection (HPLC-DAD) and high-performance liquid chromatography-electrospray ionization mass spectrometryn (HPLC-ESI/MSn). In addition, the dominant anthocyanin, cyanidin 3-O-glucoside was demonstrated cytotoxic response of human hepatocarcinoma SMMC-7721 cells, inducing live cancer cell apoptotic by flow cytometric analysis.

A simple and sensitive analytical procedure for the determination of multi-component compounds in water samples was developed and optimized using the headspace solid-phase microextraction (HSSPME) coupled with gas chromatography-maßs spectrometry (GC-MS). Ten off-flavor compounds, including geosmin (GSM), 2-methylisoborneol (2-MIB), 2-isopropyl-3-methoxypyrazine (IPMP), 2-isobutyl-3-methoxypyrazine (IBMP), β-ionone, trans-2,cis-6-nonadienal (NDE), 2,3,4-trichloroanisole (2,3,4-TCA), 2,3,6-trichroloanisole (2,3,6-TCA), 2,4,6-trichloroanisole (2,4,6-TCA), and 2,4,6-tribromoanisole (2,4,6-TBA) were used as the target analytes. The optimization of extraction parameters including fibers types, extraction time, extraction temperature, stirring rate, sample volume, and ionic strength was carried out through the univariate approach. Ten off-flavor compounds were quantified within 50 min under the optimal conditions. Calibration curves with good linearity (r2=0.990-0.998) were obtained in the range 1.0/2.0-100 ng/L, while the limits of detection for all compounds were lower than or close to the odor threshold concentration. Furthermore, the proposed method was applied to analyzing and determining the off-flavor compounds in real water samples from water-treatment plants.

Reactions of LH (L = HC[C(Me)N(2,6-Me2C6H3)]2) with MenAlCl3–n in diethyl ether afforded the adducts LH·AlMen(Cl)3–n (n = 2, 3; 1, 4; 0, 5) in good yields. Treatment of 3 at elevated temperatures in toluene resulted in LAlMeCl (2) by intramolecular elimination of methane. The controlled hydrolysis of LAlMeCl (2) with equimolar amounts of water in the presence of N-heterocyclic carbene (NHC) gave a mixture of [LAl(Me)]2(μ-O) (7) and dimeric [LAlMe(μ-OH)]2 (8). A convenient route for the preparation of [LAlMe(μ-OH)]2 (8) was the NHC-assisted controlled hydrolysis of LAlMeI (9). Stepwise hydrolysis of LAlH2 (11) gave dialuminoxane hydride [LAl(H)]2(μ-O) (12) and dialuminoxane hydroxide [LAl(OH)]2(μ-O) (13), respectively. Anhydrous treatment of LAlCl2 (1) or LAlMeCl (2) with Ag2O afforded chlorinated dialuminoxane [LAl(Cl)]2(μ-O) (14) and [LAl(Me)]2(μ-O) (7), respectively.

The chemical nature of the interaction of starch and dodecylamine (DDA), which generally act as depressant and collector, respectively, in the reverse flotation of bauxite, was investigated using starch-iodine tests. The results obtained from the blue-value measurements for starch+DDA+iodine system indicate the formation of the inclusion complex for amylose-DDA system at low DDA concentration (<2 mmol/L). However, it is less likely for amylopectin-DDA system with short helix. UV-Vis spectra of starch-iodine complexes show that each helix of amylose can accommodate two DDA molecules locating separately at its two ends, and in the helical cavity there is room available for the upcoming iodine. When concentrated DDA is tested, amylose-DDA system exhibits no characteristic starch-iodine color, owing to the presence of a compact coating of DDA molecules on starch via hydroxyl/amine hydrogen bonding. 1H NMR spectroscopy and surface tension determination help to clarify the interaction mechanism of amylose with DDA.

The effects of dispersant amount and solids loading on rheological behaviors of aqueous BeO suspensions were investigated. The relationship of viscosity and solids loading determined experimentally was compared with five various existing models. BeO aqueous suspensions exhibited a shear dependent behavior from shear thinning to shear thickening with the increasing of shear rate. The rheological behaviors of the suspensions are in reasonable accord with the model proposed by Liu, and are basically consistent with the Dabak model and Chong model, but are discrepant to other two models proposed by Krieger–Dougherty and Kitano. The maximum solids loading is estimated to be 0.577.

•The QuEChERS-based method was used to detect 4-n-OP, 4-n-NP, BPA in fish.•The Plackett-Burman factorial design for screening the main factor was timesaving.•Matrix effect was reduced by matrix-matched internal standard method.The presence of endocrine disrupting chemicals such as 4-n-octylphenol, 4-n-nonylphenol and bisphenol A in environmental samples and artificial products may cause health problems for human and organisms. This developed method was efficient for monitoring of those tracing emerging contaminates and the Plackett-Burman factorial design introduced in extraction step was timesaving. Matrix effect was also considered to ensure proper quantitation. Good linearity (r2 > 0.99), low Method Detection Limits (MDL) and Method Quantitation Limits (MQL) range from 0.18 to 0.54 ng/g and 0.60 to 1.80 ng/g were obtained. Three level spiking experiment (4, 10, 15 ng/g) showed recoveries range from 74% to 113% for 4-n-octylphenol and 4-n-nonylphenol with RSD range from 2% to 11%. The method was finally applied to the analysis of real fish samples taken from Hunan Province, China, offering a reliable and effective means for monitoring of trace emerging contaminates in fishes largely consumed by residents.