Adsorption of 4-n-nonylphenol (4-n-NP) and bisphenol A (BPA) on magnetic reduced graphene oxides (rGOs) as a function of contact time, pH, ionic strength and humic acid were investigated by batch ...techniques. Adsorption of 4-n-NP and BPA were independent of pH at 3.0- 8.0, whereas the slightly decreased adsorption was observed at pH 8.0–11.0. Adsorption kinetics and isotherms of 4-n-NP and BPA on magnetic rGOs can be satisfactorily fitted by pseudo-second-order kinetic and Freundlich model, respectively. The maximum adsorption capacities of magnetic rGOs at pH 6.5 and 293 K were 63.96 and 48.74 mg/g for 4-n-NP and BPA, respectively, which were significantly higher than that of activated carbon. Based on theoretical calculations, the higher adsorption energy of rGOs + 4-n-NP was mainly due to π–π stacking and flexible long alkyl chain of 4-n-NP, whereas adsorption of BPA on rGOs was energetically favored by a lying-down configuration due to π–π stacking and dispersion forces, which was further demonstrated by FTIR analysis. These findings indicate that magnetic rGOs is a promising adsorbent for the efficient elimination of 4-n-NP/BPA from aqueous solutions due to its excellent adsorption performance and simple magnetic separation, which are of great significance for the remediation of endocrine-disrupting chemicals in environmental cleanup.
Although exposure to antibiotics at a critical developmental time window has been implicated in mental health in observational and experimental studies, very limited bio-monitoring data are available ...for exposure to antibiotics associated with child mental disorders. The goal of our study was to examine the association between urinary exposure of children to antibiotics and mental health. The participants were 278 children from 256 eligible families in the urban–rural fringe of Fuyang city in China since June in 2017. A single-point urine sample was collected to measure the antibiotic concentrations to characterize the exposure levels. A total of 45 antibiotics from nine classes and their two metabolites were monitored through liquid chromatography electrospray tandem mass spectrometry. We used multivariable regressions to estimate the covariate-adjusted associations between urine–antibiotic concentrations and mental impairments, as assessed using the parent version of Strengths and Difficulties Questionnaire. Among the participants, ciprofloxacin was associated with an increased risk of mental disorders at both lower concentrations (
OR
= 4.06; 95%
CI
1.69–9.78) and higher concentrations
OR
= 6.04; 95%
CI
2.59–14.08). After categorizing the detected antibiotics, the positive associations were observed between abnormal score in total difficulties and higher levels exposure to fluoroquinolones (
OR
= 2.83, 95%
CI
1.38–5.80) and antibiotics preferred for veterinary use (PVAs) (
OR
= 3.20; 95%
CI
1.41–7.27), respectively. Our findings suggest that ciprofloxacin, fluoroquinolones and PVAs, probably from contaminated food or environment, may be associated with child mental disorders.
A method has been developed for the analysis of seven metabolites of phthalates in human urine by high performance liquid chromatography-tandem mass spectrometry ( HPLC-MS/MS). The urine samples were ...hydrolyzed with glucuronidase followed by purification with solid-phase extraction (SPE) cartridges. Both 0. 1% formic acid in water (v/v) and 0.1% formic acid in acetonitrile were used as the mobile phases in a gradient mode. The chromatographic separation was achieved on a phenyl column. Mass detection was then conducted by electrospray ionization in negative ion mode and multiple reaction monitoring mode. The components were quantified by stable isotope-labelled (13C-) phthalate monoester internal standards. The calibration curves of the seven phthalates metabolites showed good linear relationships in the range of 0.2-200.0 µg/L (r > 0.999 76). The recoveries at three levels were from 88.8% to 108.9% with relative standard deviations no more than 17.05%. The limits of detection of the method were 13.43-80.2 ng/L. The limits of quantification were 44.77-267.37 ng/L. This method was successfully applied to the determination of metabolism of phthalates in human urine with efficiency, increased accuracy and high sensitivity.
This study evaluated the association of maternal excessive gestational weight gain with saturated and polyunsaturated fatty acid concentrations in maternal and cord serum.
We included 77 pairs of ...women and their newborns and classified them into three groups as follows: mothers with normal gestational weight gain and their babies with normal birth weight in group I (30 pairs), mothers with excessive gestational weight gain and their babies with normal birth weight in group II (30 pairs), and mothers with excessive gestational weight gain and their macrosomic babies in group III (17 pairs). Serum fatty acid concentrations were determined through gas chromatography-mass spectrometry.
No remarkable difference in maternal dietary intake was observed among the three groups. C16:0, C18:0, eicosapentaenoic acid, and docosahexaenoic acid concentrations were significantly higher in group III mothers than in group I mothers. Compared with group I neonates, total saturated and polyunsaturated fatty acid concentrations were significantly lower but total n-3 polyunsaturated fatty acid and docosahexaenoic acid concentrations were significantly higher in group II neonates (p<0.05). The n-6: n-3 ratio in maternal and cord serum was approximately 10:1 and 1.5:1, respectively.
Women with excessive gestational weight gain who deliver a macrocosmic neonate tend to have higher total saturated fatty acid concentrations but lower docosahexaenoic acid concentrations in their neonate cord serum. Fatty acid concentrations in maternal and cord serum are not associated with maternal dietary pattern.
Emotional and behavioral problems (EBPs) of adolescents is a worldwide public health problem. Bisphenol A (BPA) and phthalate (PAEs) are prevalent and potentially toxic to human health. Therefore, ...this study aimed to investigate the associations between urinary level of BPA, PAEs, 8-iso-prostaglandin-F2α (8-iso-PGF2α), and EBPs.
A total of 865 Chinese adolescents were included in this study and EBPs was assessed using the Strengths and Difficulties Questionnaire (SDQ). Urinary concentrations of BPA and seven PAEs metabolites in adolescents were determined by high performance liquid chromatography-tandem mass spectrometry. Urinary 8-iso-PGF2α concentration was detected by enzyme-linked immunosorbent assay (ELISA). Spearman rank correlation analysis, multivariate logistic regression analysis, restricted cubic spline functions were used to explore the relationship between the levels of BPA, PAEs, 8-iso-PGF2α and EBPs.
BPA and PAEs metabolites were positively associated with EBPs in Chinese adolescents. And the 8-iso-PGF2α was significantly non-linearly correlated with emotional symptoms, conduct problems, peer problems and total difficulties. Furthermore, 8-iso-PGF2α may partially mediate the association between BPA and PAEs exposure and EBPs.
This study was a cross-sectional study, the cause-effect relationship between BPA, PAEs exposure and EBPs could not be determined. A single spot urine sample for BPA and PAEs exposure characterization maybe could not represent their long-term exposure level.
High exposure of BPA and PAEs are associated with EBPs, which may be partly mediated by oxidative stress among adolescents. The results of this study could provide certain ideas for subsequent related research.
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•Adolescents were widely exposed to bisphenol A (BPA) and phthalates (PAEs).•BPA and PAEs were associated with emotional and behavioral problems (EBPs).•Oxidative stress mediated the association of BPA, PAEs and EBPs.
Nano-titanium oxide (nano-TiO
2
) was synthesized and characterized by using XRD, TEM, XPS and FTIR. The effect of contact time, solid content, pH, foreign anions, ionic strength, humic acid (HA) and ...temperature on the removal of Pb(
ii
) by nano-TiO
2
were investigated using a batch technique. The batch results showed that the adsorption of Pb(
ii
) on nano-TiO
2
significantly decreased with increasing ionic strength at low pH conditions, whereas the ionic strength-independent adsorption was observed at high pH, indicating that the ion exchange and inner-sphere surface complexation dominated the adsorption of Pb(
ii
) at low and high pH, respectively. The further evidences were provided by the effect of foreign anions and HA. The maximum adsorption capacity of Pb(
ii
) on nano-TiO
2
calculated from a Langmuir model at pH 5.0 and 293 K was 30.8 mg g
−1
, which was significantly higher than commercial P25 TiO
2
(15.0 mg g
−1
). The thermodynamic parameters showed that the adsorption of Pb(
ii
) on nano-TiO
2
was an endothermic and spontaneous process. The hydroxyl groups of nano-TiO
2
were responsible for the highly effective adsorption of Pb(
ii
) by XPS analyses. Based on surface complexation modeling, a diffuse layer model gave excellent fitting for the pH-edge adsorption data. The results indicated that the nano-TiO
2
could be used as a suitable adsorbent for the removal of heavy metals from large volumes of aqueous solutions in environmental cleanup.
The ion exchange and inner-sphere surface complexation were inferred as the adsorption mechanisms of Pb(
ii
) on nano-TiO
2
.
The change in the chemical properties of graphene oxides (GOs) can be tuned by the sonochemical approach. The layers of GOs were significantly decreased by the sonochemical approach as seen from high ...resolution transmission electron microscopy and atomic force microscopy analysis. Abundant hydroxyl groups and carboxyl groups were introduced with increasing ultrasonic time by the analysis of Raman, FTIR, UV-vis absorbance spectroscopy and XPS techniques. The adsorption of U(vi) on GOs significantly increased at pH 1.0-6.0, whereas decreased adsorption was observed at pH > 8.0. The adsorption capacities of GOs increased with increasing ultrasonic time. According to EXAFS analysis, the interaction mechanism between radionuclides and GOs was inner-sphere surface complexation. Such an efficient approach to control the chemical properties of GOs further promotes its applications in environmental cleanup.
•A core-shell magnetic dummy molecularly imprinted polymers were successfully prepared.•The MDMMIPs had good adsorption capacity, selectivity and fast adsorption rate to mPAEs.•The MDMMIPs were ...successfully used to extract mPAEs from urine samples.
In this work, a simple and efficient dispersive solid-phase microextraction (DSPME) method based on magnetic dummy molecularly imprinted polymer nanoparticles (MMIPs) was developed for the extraction of five phthalate monoesters (mPAEs) from human urine samples. The MMIPs synthesized by sol–gel reaction and surface imprinting were analyzed by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometry, and thermogravimetric analysis. The obtained results demonstrate that the MMIPs prepared herein are characterized by high selectivity, good adsorption capacity (124.5 mg/g), excellent reusability (over five sorption–desorption cycles), and fast adsorption rates (about 30 min to equilibrium) with respect to five mPAEs. In addition, the MMIPs can be easily separated from the sample solutions due to their good magnetic susceptibility (34.0 emu/g). Using MMIPs as sorbent material in DSPME, five mPAEs in three human urine samples were extracted, and then analyzed by high-performance liquid chromatography (HPLC). Based on the obtained results, this method shows good linearity in the range of 1–100 mg/L for monomethyl phthalate, monoethyl phthalate, and monobutyl phthalate, in the range of 1–80 mg/L for monobenzyl phthalate, and in the range of 1–50 mg/L for monoethylhexyl phthalate. Moreover, good recovery (80.0%–101.0%) of all five mPAEs was observed at three spiked level with relative standard deviations of 0.6–6.6%. Overall, the results reported herein indicate that the prepared MMIPs can be used as sorbent material for the dispersive solid-phase microextraction of phthalate monoesters in human urine samples.
Figure 1a has been published incorrectly in the original article in which there is a mistake in characterization of graphene oxide (XRD pattern) due to the odd repetition of background. The correct ...version of Fig. 1a is provided in this correction.
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