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Graphene-Fe O nanoparticles were prepared using one-step solvothermal method and characterized by X-ray diffraction, FTIR spectroscopy, scanning electron microscopy, and vibrating sample magnetometry. The results demonstrated that Fe O nanoparticles were homogeneously anchored on graphene nanosheets. The as-synthesized graphene-Fe O nanoparticles were employed as sorbent for magnetic solid-phase extraction of sulfonamides in milk prior to capillary electrophoresis analysis. The optimal capillary electrophoresis conditions were as follows: 60 mmol/L Na HPO containing 2 mmol/L ethylenediaminetetraacetic acid disodium salt and 24% v/v methanol as running buffer, separation voltage of 14 kV, and detection wavelength of 270 nm. The parameters affecting extraction efficiency including desorption solution, the amount of graphene-Fe O nanoparticles, extraction time, and sample pH were investigated in detail. Under the optimal conditions, good linearity (5-200 μg/L) with correlation coefficients ≥0.9910 was obtained. The limits of detection were 0.89-2.31 μg/L. The relative standard deviations for intraday and interday analyses were 4.9-8.5 and 4.0-9.0%, respectively. The proposed method was successfully applied to the analysis of sulfonamides in milk samples with recoveries ranging from 62.7 to 104.8% and relative standard deviations less than 10.2%.

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In this work, an aptamer-based colorimetric method for the detection of tetracycline (TC) was established by employing gold nanoparticles (AuNPs) as the colorimetric probe.

Converting CO 2 into high-value chemicals has been regardeda sa nimportant solution for as ustainable low-carbon economy.I nt his work, we have theoretically designed an innovative strategy for the absorptiona nd activation of CO 2 by the electride N3Li, that is,1 ,3,5(2,6)-tripyridinacyclohexaphane (N3) intercalated by lithium.D FT computations showed that the interaction of CO 2 with N3Li leads to the catalytic complex N3Li(h 2 -O 2 C), which can initiate the radical-controlled reduction of anotherC O 2 to form organic acids through radical reactions in the gas phase. The CO 2 reductionc onsists of four steps:( 1) The formation of N3Li(h 2 -O 2 C) through the combinationo fN 3Li and CO 2 ,(2) hydrogen abstraction from RH (R = H, CH 3 ,a nd C 2 H 5 )b yN 3Li(h 2 -O 2 C) to form the radical RC and N3Li(h 2 -O 2 C)H, (3) the combination of CO 2 and the radicalRC to form RCOOC,and (4) intermolecular hydrogen transferf rom the intermediateN 3Li(h 2 -O 2 C)H to RCOOC.I nt he whole reactionp rocess, the CO 2 moiety in the complex N3Li(h 2 -O 2 C) maintains ac ertainr adical character at the carbon atom of CO 2 and plays as elf-catalyzing role. This work represents the first example of electridesponsored radical-controlledC O 2 reduction,a nd thus provides an alternative strategy for CO 2 conversion.

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