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Present work depicted a novel electrochemical sensor fabricated with magnetic carbon dots (M-CDs) and cetyltrimethylammonium bromide (CTAB) modified glassy carbon electrode (GCE) for selective measurement of 3,3′,5,5′-tetrabromobisphenol A (TBBPA) in beverages. The M-CDs composite material revealed good electrocatalytic activity, and CTAB has strong hydrophobic interaction which enable it have good enrichment capacity of hydrophobic compounds, and combination of them further enhances the electrochemical signal. Hence CTAB decoration can markedly improve the detection performance of TBBPA. Electrochemical properties of the fabricated sensor was investigated through performing cyclic voltammetry (CV). The morphology and functional groups of the modified materials were examined with transmission electron microscope (TEM) and Fourier transform infrared spectroscopy (FTIR). The results indicated that the synthesized material had a spherical-like structure, good dispersion properties and plenty of functional groups on the surface. The effects of incubation potential, incubation time, pH of electrolyte, and scanning rate on oxidation peak current were investigated. Under optimal conditions, the designed sensor had good linear range of 1 nM–1000 nM, and the detection of limit of the constructed sensor was 0.75 nM. The constructed sensor was utilized to detect TBBPA in vitamin water, scream drink and genki forest, and satisfactory detection performance had been achieved. • Magnetic carbon dots (M-CDs) were facile prepared with simple method. • M-CDs composite material revealed good electrocatalytic activity. • Novel electrochemical sensor was developed with M-CDs and CTAB. • Developed sensor provided good sensitivity of 0.75 nM for tetrabromobisphenol A. [ABSTRACT FROM AUTHOR]

Organochlorine pesticides (OCPs) have received much attention due to their toxicity. Reliable methods to monitor their residues in the environment are needed. Here, magnetic polyamidoamine dendrimers were prepared by co-precipitation, Michael addition, and amidation. The magnetic polyamidoamine dendrimers demonstrated good adsorption ability for OCPs—this feature was utilized to construct a sensitive tool for monitoring OCPs in water samples. The proposed method provided remarkable linearity from 0.1 to 500 μg/L and satisfactory limits of detection from 0.012 to 0.029 μg/L. The spiked recoveries of the four target analytes were 91.8%−103.5% with relative standard deviations less than 4.5%. The magnetic materials had good reusability. The results indicated that the resulting method was an efficient, easy, rapid, economical, and eco-friendly tool for monitoring OCPs in aqueous samples. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• MNP@PAMAM-Gn@C 60 were firstly synthesized by simple method. • Modification with PAMAM and C 60 endow target magnetic material excellent adsorption. • MNP@PAMAM-Gn@C 60 based MSPE provided high enrichment and sensitivity for PCBs. • The proposed method was reliable and effective for measurement of PCBs in beverages. Polychlorinated biphenyls (PCBs) are persistent organic pollutants which are widely present in environment and harmful to human health. In this study, an efficient and convenient magnetic solid phase extraction method with C 60 modified magnetic polyamido-amine (PAMAM) dendrimers as sorbents was established for enriching trace amounts of PCBs in beverage samples. Gas chromatography-tandem mass spectrometry (GC–MS/MS) was utilized for analysis of PCBs. Parameters affecting extraction efficiency were optimized. Under optimal parameters, good linearity can be achieved in concentration range of 0.001–20 μg L−1 and 0.002–20 μg L−1 for nine selected PCBs. The limits of detection for PCBs were in the range of 0.1–0.2 ng L-1. The spiked recoveries were in the range of 87.0 %–115.1 % (n = 3). The results proved that this established method was reliable for monitoring trace PCBs in beverage samples. [ABSTRACT FROM AUTHOR]

Polychlorinated biphenyls (PCBs) are a kind of hazardous persistent organic contaminants and widely present in nature due to large consumption in the past. Although PCBs have been banned in many countries of the world, they are still present at trace level in food and water samples. It is of significant value to establish reliable enrichment and detection method. Based on the conversion of the hydrophilicity and hydrophobicity from heptanoic acid under alkali and acid, increasing the contact area between heptanoic acid and PCBs, a new switchable solvent micro-extraction method for PCBs from beverages was developed with good extraction efficiency using heptanoic acid as the extractant prior to gas chromatography-tandem mass spectrometry (GC-MS/MS). The key parameters that had impact on enrichment of PCBs were investigated in detail. Under the optimal conditions, a good linearity can be achieved in a concentration range of 0.01–20 μg L−1 with the correlation coefficients of 0.9978–0.9994. Limits of detection for PCB28, PCB53, PCB206 were 3 ng L−1 and PCB118 was 5 ng L−1 while other target PCBs were 2 ng L−1. Intra-day and inter-day precisions were in the range of 1.9–4.2% and 2.1–4.2％(relative standard deviation, RSD, n = 6), respectively. The real sample spiked recoveries of the targets were in the range of 93.2–114.3％ (n = 3). The enrichment factors were in the range of 16.2–17.9. The results proved that this method was reliable for monitoring trace PCBs in beverage samples and will help for future assessments of impacts on human and animal health. • A switchable solvent microextraction method was established for enrichment of PCBs. • Enrichment is due to conversion between hydrophobic and hydrophilic forms of heptanoic acid. • The method was reliable, sensitive, simple and effective for measurement of PCBs. [ABSTRACT FROM AUTHOR]

In this study, graphene oxide modified magnetic polyamidoamine dendrimers (MNPs@PAMAM-G2.0@GO) nanoparticles were successfully prepared by amidation method. The obtained MNPs@PAMAM-G2.0@GO nanocomposites were examined by fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), scanning electron microscope (SEM) and transmission electron microscopy (TEM), etc. MNPs@PAMAM-G2.0@GO exhibited excellent adsorption property and was investigated for magnetic solid phase extraction (MSPE) of polycyclic aromatic hydrocarbons (PAHs) from water. The detection of extracted PAHs was accomplished by high performance liquid chromatography (HPLC) and gas chromatography tandem mass spectrometry (GC-MS/MS). The target PAHs included anthracene (ANT), pyrene (PYR), fluoranthene (FLT), carbazole (CB), 7-methylquinoline (7-MQL), 9-methylcarbazole (9-MCB), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DBT). Important operation parameters for MSPE that could affect the extraction efficiencies of PAHs were investigated in detail. Under optimal parameters, the constructed method demonstrated excellent linear range with 0.001–10 μg L−1 for analytes and low limits of detection within the range of 0.11–0.9 ng L−1. The spiked average recoveries of PAHs in natural water samples ranged from 92.5% to 105.2%. The promising results indicated that MNPs@PAMAM-G2.0@GO could be employed to efficiently extract PAHs from aqueous samples. [Display omitted] • Magnetic dendrimers modified with graphene oxide exhibited good adsorption for PAHs. • An efficient magnetic solid phase extraction method was developed for PAHs. • The method provided advances of rapidity, sensitivity, easy operation and low cost. [ABSTRACT FROM AUTHOR]

4-Carboxyphenylboronic acid was used as the single precursor to facilely prepare fluorescent carbon quantum dots by one-step solvothermal method. The as-obtained carbon dots (CDs) exhibited highly selective and sensitive for benzo[a]pyrene (BaP), and may be a splendid sensor for sensing BaP. The principle was that the as-prepared CDs could form a complex with BaP through hydrophobic interaction which causes the decrease of fluorescence intensity of CDs by static quenching principle. The constructed fluorescent sensor exhibited excellent linearity ranged from 0.002 to 0.06 μg mL−1 and provided a low limit of detection of 0.16 ng mL−1. The experimental results showed that this fluorescent sensor resulted in simplicity, rapidness, low cost, short analytical time, and high sensitivity and stability. Validation with real water samples endowed the sensor high reliability and feasibility for BaP determination in practical application in various samples. • Selective carbon dots are facilely derived from 4-carboxyphenylboronic acid. • Carbon dots exhibit good selective and sensitive for BaP. • Fluorescence detection of BaP is based on static quenching mechanism. • The sensor shows high feasibility and provides good sensitivity of 0.16 ng mL−1. [ABSTRACT FROM AUTHOR]

In present work, we reported a new nanomaterial nano Fe0 decorated with SiO 2 and dopamine by self-assembly method (Fe@SiO 2 @PDA). A sensitive method for determination of Sudan pollutants in aqueous samples was developed using Fe@SiO 2 @PDA as magnetic solid phase extraction adsorbents prior to high-performance liquid chromatography with variable wavelength detector. The possible parameters which would affect the enrichment have been optimized. The best parameters were as follows: elutent, 4.5 mL methanol; adsorbent dosage, 30 mg; adsorption time, 20 min; elution time, 18 min; sample pH 7; sample volume, 40 mL. The experimental results demonstrated that Fe@SiO 2 @PDA exhibited good adsorption properties to Sudan Red dyes. The established method provided excellent linear ranges over 0.01–50 μg L−1 and detection limits ranged from 2.0 to 5.1 ng L−1 for Sudan red I-IV. The developed method was also evaluated with real water samples and the results demonstrated that it was of applicative value owing to its merits including robustness, easy operation, fastness, cheapness and high enrichment efficiency, and had great prospect in environmental fields. • Fe@polydopamine was easily prepared and earned excellent enrichment capability. • Modification with dopamine endowed nanoscale zero valent iron with new applications. • Established method provided good sensitivity from 2 to 5.1 ngL−1 for Sudan I-IV. • The developed method earned merits of various merits and great prospect. [ABSTRACT FROM AUTHOR]

An ordered g–C 3 N 4 – and polyaniline-modified titanium oxide nanotube array (g–C 3 N 4 – and PANI-co-modified TiO 2 NTAs) was successfully synthesized and used as a photocatalyst. Polyaniline (PANI) was coated onto TiO 2 NTAs by electrochemical polycondensation, and g-C 3 N 4 was deposited via the soaking adsorption method. The photocatalysts were examined by several technologies. The experiments demonstrated that the amount of g-C 3 N 4 and PANI, as well as the initial pH value, had significant effects on the photocatalytic efficiency. The resulting photocatalysts exhibited high visible light photocatalytic ability for tetrabromobisphenol A (TBBPA) for two reasons. First, PANI expanded the light absorption into the visible region. Second, rapid and efficient separation of photoinduced charges from the photogenerated potential difference were produced at the contact interface of g-C 3 N 4 and PANI-co-modified TiO 2 NTAs. The •OH, • O 2 − and h+ were dominant components for the photocatalytic degradation of TBBPA. In addition, the g-C 3 N 4 and PANI-co-modified TiO 2 NTAs have excellent long-term stability. • g–C 3 N 4 – and PANI-co-modified TiO 2 NTAs was synthesized by a facile method. • g–C 3 N 4 – and PANI-co-modified TiO 2 NTAs markedly enhanced photocatalytic activity. • g-C 3 N 4 and PANI co-modification generated strongly synergistic effect. [ABSTRACT FROM AUTHOR]

2,4,6-Trinitrophenol (TNP) has absorbed much concerns because of its toxic effect and threat on the environment, which results from the fact that it is an important and universal reagent widely utilized for manufacturing many products. It is of great necessity to explore facile and efficient methods for monitoring TNP. In present study, carbon dots (CDs), a new carbonaceous nanomaterial with strong fluorescence, was applied to build a novel sensor for highly sensitive and selective detection of TNP. In the sensing procedure, the fluorescence intensity of as-prepared CDs was diminished with the presence of TNP due to inner filter effect (IFE) quenching mechanism. The sensitivity of the fluorescent sensor was very high with limit of detection down to 5.37 ng mL−1. This fluorescent sensor was evaluated and excellent spiked recoveries were gained, which demonstrated that the developed sensor would be a robust tool for environmental applications. Unlabelled Image • Fluorescent CDs were prepared by a facile and reliable method. • Sensitive sensor was developed with carbon dots based on inner filter effect. • This sensor earned high sensitivity with LOD of 5.37 ng mL−1. [ABSTRACT FROM AUTHOR]