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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]

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]

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]

Polyamidoamine dendrimer decorated Fe 3 O 4 magnetic nanoparticles was synthesized and grafted with 4-mercaptobenzoic acid (4-MBA). The resulting material was utilized to develop an effective magnetic solid phase extraction method in combination with high performance liquid chromatography for trace determination of polycyclic aromatic hydrocarbons including phenanthrene (PHE), anthracene (ANT), fluoranthene (FLT), pyrene (PYR) and benzo(a)pyrene (BaP). The MNPs@G3.0@4-MBA exhibited to be an efficient extracting medium due to the existence of terminal benzene ring groups, the internal pores, and strong hydrophobic interactions and π-π interactions. The experiments demonstrated that the proposed method possessed excellent linearity in the concentration range of 0.1–300 μg L−1 with correlation coefficients (R) larger than 0.997, and the limits of detection (LODs, S/N = 3) according to the ratio of signal to noise equal to three of PHE, ANT, FLT, PYR and BaP were 0.014 μg L−1, 0.032 μg L−1, 0.055 μg L−1, 0.027 μg L−1 and 0.039 μg L−1, respectively. The proposed method was applied to real water samples and the spiked recoveries were over the range of 92–99%. The results showed that the method earned good repeatability and high sensitivity, and the as-prepared materials were stable and reusable, which displayed that the proposed method would have a wonderful application prospect. Image 1 • 4-Mercaptobenzoic acid grafted PAMAM dendrimer decorated Fe 3 O 4 was prepared. • MNP@G3.0@4-MBA exhibited excellent adsorption capacity for PAHs. • The method provided good sensitivity with low LODs of 0.014–0.055 μgL−1 for PAHs. • The method was robust, simple and of low cost and good repeatability. [ABSTRACT FROM AUTHOR]