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[Display omitted] • Porous geopolymer is introduced as adsorbent for MSPE for the first time. • Difunctional Zn@MGeo is constructed as highly selective adsorbents for extraction of fluoroquinolones antibiotics. • Zn@MGeo is comprehensively characterized and adsorption mechanism is studied in detail. • The established MSPE-UHPLC-MS/MS has achieved rapid, sensitive and accurate detection of fluoroquinolones in complex samples. A novel Zn@MGeo sorbent was easily constructed and can bind with FQs through the synergistic effect of electrostatic interaction and coordination. With the Zn@MGeo as sorbent, a MSPE-UHPLC-MS/MS method was established for simultaneous detection of FQs in complex matrices. The whole extraction process could be completed using 6.0 mg sorbent within 10 min under the optimal conditions. The established quantitative method obtained a wide linear range (0.01–200 μg/kg, R2 > 0.9987), high sensitivity (LODs: 0.005–0.05 μg/kg) and negligible matrix effect. The method was applied for analysis of real samples, with recoveries between 75.6% and 103.7%. In addition, the sorbent could be reused at least 9 times without reducing the adsorption performance. In general, the established method not only proposes a novel sorbent for FQs extraction, but also provides a powerful tool for rapid and sensitive detection of FQs in food matrices with practical application value. [ABSTRACT FROM AUTHOR]

Abstract: As a representation of metalloproteins, metallothionein (MT), which plays important biological and environmental roles such as in the metabolism and detoxification of some metals, was detected at bismuth film electrode (BiFE) by differential pulse anodic stripping voltammetry (DPASV). In pH 2–5.5, two well-defined anodic peaks were produced and attributed to the Zn2+ and Cd2+ inherent to MT. The calibration plot of DPASV peak currents for Cd2+ inherent to MT versus MT concentrations showed a good linearity with a detection limit of 3.86×10−8 mol/L for MT. As a non-toxic excellent electrode material, BiFE shows good performance for detecting MT, and is expected to find further applications in the studies of many other metalloproteins. [Copyright &y& Elsevier]

The impediment of heterogeneous electron transfer (ET) reactions of several electroactive species by alkanedithiol self-assembled monolayers (SAMs) and those covered with Au nanoparticles was investigated. It was found that, when densely packed 1,6-hexanedithiol and 1,9-nonanedithiol SAMs were formed with and without adsorbed gold nanoparticles, Fe(CN)63- reduction became extremely sluggish. The attachment of Au nanoparticles does not appear to improve the electronic communication between the solution species and the underlying Au electrode surface. On the other hand, Ru(NH3)63+ and ferrocenecarboxylic acid both exhibited quasi-reversible redox waves at these surfaces. The variation of impediment were attributed to the different electron transfer mechanisms for these redox species. The adsorption of Au nanoparticles onto alkanedithiol SAMs was estimated by flow injection quartz crystal microbalance (FI-QCM), showing a rapid adsorption process. Amounts of Au nanoparticles did not vary between the two different alkanedithiols. Finally, we quantified the adsorption of Au nanoparticles at the QCM crystal modified with a 1,9-nonanedithiol SAM in air. A surface coverage of 2.56% was obtained. [Copyright &y& Elsevier]

Nonlinear regression algorithms have been extensively applied in the parametric analyses of electrochemical impedance spectroscopy (EIS). However, the problem of how to provide good initial estimates of parameters automatically has not been thoroughly solved yet. For this reason, this paper offers a hybrid algorithm, which consists of the genetic algorithm (GA) based on probability theory and the deterministic computation based on analytic theory. The paper improves the usual GAs and puts forward the concept of weighting mutation. The hybrid algorithm overcomes the shortcoming that the usual GAs are liable to produce premature convergence. This paper has preliminarily solved the problem of how to produce good initial estimates of parameters automatically by a program design in the data processing of EIS. In principle, the design idea of the hybrid algorithm is of universal validity and can be used for solving the problem of how to provide good initial estimates of parameters automatically, which appears in many kinds of nonlinear regressions. [Copyright &y& Elsevier]

Dietary intake is the major route for the exposure of residents to short-chain chlorinated paraffins (SCCPs). SCCPs are classified as persistent organic pollutants (POPs) by the Stockholm Convention since May 2017. This study assessed the general population's dietary exposure to SCCPs through supermarket products. Five food categories, which included 40 food species, were collected from five supermarkets in April 2019. The SCCP concentrations in all food matrices varied between 58.6 and 1977 ng g−1 dry weight (dw), with the average and standard deviation (SD) value of 301 ± 379 ng g−1 dw. Generally, the SCCP concentrations in animal-origin food matrices were higher than those in plant-origin food matrices. The C 10 Cl 7 congeners were predominant among the congener groups of SCCPs. The proportion of C 10 congeners in the animal-origin food samples (29.8%) was lower than that in the plant-origin food samples (39.7%), and the C 13 congeners showed a contrasting result. The estimated daily intake (EDI) of SCCPs through dietary intake for the residents was 3109 ng kg−1 day−1, which is much lower than the standards of European Food Safety Authority (10 mg kg−1 day−1) for SCCPs. Risk assessment based on the supermarket foods indicated that SCCP exposure through dietary intake does not cause adverse effects to human health according to the margin of exposure (MOE). Image 1 • SCCP levels in animal food were three times higher than those in plant food. • SCCP concentrations were positively related to lipid content (p < 0.01). • C 10 Cl 7 congener groups were predominant in food samples. • SCCP exposure through dietary intake poses no adverse effects according to the NOAEL. [ABSTRACT FROM AUTHOR]

[Display omitted] • Comparative proteomics explored the molluscicidial mechanism of PBQ against P. canaliculata. • A total of 245 DEPs were identified in snails following the exposure of PBQ. • DEPs were enriched in the ribosome, translation process and purine biosynthesis pathway. Angiostrongylus cantonensis is a zoonotic parasitic nematode that is the most common cause of human eosinophilic meningitis. The invasive apple snail Pomacea canaliculata is an important intermediate host of A. cantonensis and contributes to its spread. P. canaliculata control will help prevent its invasion and transmission of A. cantonensis. The new molluscicide PBQ (1-(4-chlorophenyl)-3-(pyridin-3-yl)urea) exhibits great potency against P. canaliculata and has low toxicity against mammals and non-target aquatic organisms. We studied the mode of action of PBQ using TMT-based comparative quantitative proteomics analysis between PBQ-treated and control P. canaliculata snails. A total of 3151 proteins were identified, and 245 of these proteins were significantly differentially expressed with 135 downregulated and 110 upregulated. GO and KEGG enrichment analyses identified GO terms and KEGG pathways involved in de novo purine biosynthesis, ribosome components and translation process were significantly enriched and downregulated. The results indicated that PBQ treatment had substantial effects on the synthesis of genetic material, translation process, and protein synthesis of P. canaliculata and were likely the main cause of snail mortality. [ABSTRACT FROM AUTHOR]

Abstract: A special method “conduit synthesis technology” has been utilized to produce spherical nickel hydroxide powders with different chemical compositions. Three kinds of powers A, B, C were prepared by chemically coprecipitating Ni, Co, Zn, Ca, Mg and Cu. It was found that powder B produced better performance than the others. The discharge capacities of powder B could achieve 280mAhg−1 for both 1C and 2C rates at 65°C, respectively. The cyclic voltammetry analysis showed that the difference between the oxidation potential and the oxygen evolution potential of powder B is 122mV. It indicated that Co could improve conductivity of electrons, restrict the oxygen evolution reaction and thus promote the high rate charge/discharge and high-temperature performance. Ca and Mg might effectively enhance the oxygen evolution potential in the charge process. Furthermore, the proper addition of Zn, Ca and Cu could lower the ionization energy and elevated the transition energy, and thus the transfer of electrons in electrode materials was accelerated and the electrochemical performance of nickel hydroxide electrode was improved. It was a promising way to improve the electrochemical performance of spherical nickel hydroxide for Ni–MH batteries. [Copyright &y& Elsevier]