A facile one-pot green synthesis of ß-cyclodextrin decorated porous graphene nanohybrid as a highly efficient adsorbent for extracting aflatoxins from maize and animal feeds.

In this paper, ß-cyclodextrin (ß-CD) supported on porous graphene nanohybrid (ß-CDPG) was obtained by self-assembly of functionalized graphene nanosheets into a three-dimensional network in the presence of ascorbic acid via an in situ graphene oxide reduction and ß-CD functionalization process during a hydrothermal reaction. The prepared supramolecular nanohybrid was further packed into a reusable syringe filter holder and applied as an adsorbent for solid phase extraction of four aflatoxins (B1, B2, G1, G2). Under optimal conditions, the detection limits and linear dynamic ranges were achieved in the range of 0.0075-0.030 µg kg-1 and 0.025-100 µg kg-1, respectively and the relative standard deviations were less than 6.1%. Good recoveries were observed for analyzing target AFs in maize and cereal-based chicken feed samples ranged from 90.5 to 105%. The method offered simultaneous advantages of high supramolecular recognition and enrichment capability of ß-CD and the high specific surface area of the porous graphene.

Cerium-doped flower-shaped ZnO nano-crystallites as a sensing component for simultaneous electrochemical determination of epirubicin and methotrexate.

A glassy carbon electrode (GCE) was modified with cerium-doped ZnO nanoflowers (Ce-ZnO/GCE) to obtain a sensor for direct simultaneous detection of the cancer drugs epirubicin and methotrexate. XRD, SEM and EDX techniques were used to characterize their morphology and structure. Electrochemical impedance spectroscopy was applied to characterize the electrochemical features of the modified GCE. The experimental conditions were optimized. Diffusion coefficients and heterogeneous rate constants were determined for the oxidation of epirubicin. The differential pulse voltammetric response to epirubicin has a peak near 0.7 V (vs. Ag/AgCl at a scan rate of 50 mV s-1) and is linear in the 0.01 to 600 µM concentration range, and the detection limit is 2.3 nM (S/N = 5). The differential pulse voltammetric response to methotrexate has a peak near 0.75 V (vs. Ag/AgCl and the same scan rate) and is linear in the 0.01 to 500 µM concentration range, and the detection limit is 6.3 nM (S/N = 5). The method was applied to the simultaneous determination of epirubicin and methotrexate in pharmaceutical injections and in spiked diluted blood specimens. Graphical abstractSchematic of an electrochemical sensor based on Ce-doped ZnO nano-flowers modified glassy carbon electrode for detecting epirubicin.

Application of nanoclay for preconcentration of ultra trace amounts of palladium in environmental samples prior to its determination by ETAAS.

In the present work, a batch preconcentration technique using nanoclay with 5-(4-dimethylaminobenzylidene)rhodanine coupled with electrothermal atomic absorption spectrometry was developed for the separation and determination of trace amounts of palladium. In this method, the sample solution was stirred with nanoclay as an adsorbent. Then, adsorbed palladium was subsequently eluted with HCl in acetone (1.5 mol L−1) and, finally, this eluate was injected to electrothermal atomic absorption spectrometry. Under the optimum conditions, the limit of detection and linear dynamic range were found to be 2.6 and 10.0­133 ng L−1 (in original solution), respectively. Furthermore, the enrichment factor and relative standard deviation of seven replicate determinations were 148 and ±5.1 %, respectively. This suggested method is simple, selective and sensitive and can be applied to the extraction and determination of palladium in water, tea leaves, synthetic sample and certified reference material with satisfactory results.