Influence of the Amide Groups in the CO2/N2 Selectivity of a Series of Isoreticular, Interpenetrated Metal–Organic Frameworks

Here we report the use of a pillaring strategy for the design and synthesis of three novel amide-functionalized metal–organic frameworks (MOFs), TMUs-22/-23/-24, isoreticular to the recently reported imine-functionalized TMU-6 and TMU-21 MOFs. An extensive study of their CO2 sorption properties and selectivity for CO2 over N2, from single gas sorption isotherms to breakthrough measurements, revealed that not only the incorporation of amide groups but also their accessibility is crucial to obtain enhanced CO2 sorption and CO2/N2 selectivity. Therefore, the MOF with more accessible amide groups (TMU-24) shows a CO2/N2 selectivity value of ca. 10 (as revealed by breakthrough experiments), which is ca. 500% and 700% of the selectivity values observed for the other amide-containing (TMU-22 and TMU-23) and imine-containing (TMU-6 and TMU-21) MOFs.This work was supported by the Spanish MINECO (projects PN MAT2015-65354-C2-1-R and MAT2013-45008-P), the Catalan AGAUR (project 2014 SGR 80), and the ERC under the EU FP7 (ERC-Co 615954). I.I. and E.V.R.F. thank the MINECO for their RyC fellowships RYC-2010-06530 and RyC-2012-11427 and V.G. is grateful to the Generalitat de Catalunya for a Beatriu de Pinós Fellowship (2014 BP-B 00155). ICN2 acknowledges the support of the Spanish MINECO through the Severo Ochoa Centers of Excellence Program, under Grant SEV-2013-0295. E.V.R.F. and J.S.A. acknowledge the Generalitat Valenciana for PROMETEOII/2014/004. Support of this investigation by Tarbiat Modares University is gratefully acknowledged

A new electrochemical sensor for the detection of fentanyl lethal drug by a screen-printed carbon electrode modified with the open-ended channels of Zn(ii)-MOF

Fentanyl is a potent, effective analgesic and narcotic drug widely used for anesthesia and chronic pain control. In this study, a simple electrochemical method for the detection of fentanyl in aqueous solutions was developed. The modification of a screen-printed carbon electrode (SPCE) was performed by casting a metal-organic framework (MOF) on its surface. The characterization of the zinc-based MOF (Zn(ii)-MOF) modifier was investigatedviascanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) techniques. The differential pulse voltammetry (DPV) technique was used for evaluating the fentanyl electrochemical behavior on the electrodes. The optimum experimental conditions were investigated by examining the effects of the scan rate and pH on the cyclic voltammetry (CV) and DPV responses, respectively. The results showed that fentanyl has an irreversible behavior at the potential of 0.9 V and its current increases in the presence of MOF. The application of the presented electrode with the DPV method showed a detection limit of 0.3 μM in the concentration range of 1-100 μM (linear range) for the fentanyl in an aqueous solution. The modified electrode was successfully used to determine the low levels of fentanyl in urine and plasma as the real samples. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2020

Electrochemical determination of levodopa on a reduced graphene oxide paste electrode modified with a metal-organic framework

Developing easy-to-use sensors for monitoring of biomarkers which are related to human health is essential. Levodopa (L-DOPA) is a critical neurotransmitter that mainly uses for effective therapy of Parkinson's disease. This study introduces a novel reduced graphene oxide (RGO) paste electrode (PE), RGOPE, which is modified with a microporous metal-organic framework (MOF) as a sensing interface in the electrochemical determination of the L-DOPA. The electrochemical behavior of the modified RGOPE was studied by cyclic voltammetry (CV), square wave voltammetry (SWV), electrochemical impedance spectroscopy (EIS) and chronoamperometry techniques. The influence of parameters such as the scan rate and pH value on the peak current were investigated. Under the optimal condition, the modified RGOPE as a sensor presented a capability in highly sensitive sensing of the L-DOPA at a typical working potential of 0.56 V vs. Ag/AgCl. The sensitivity, linear dynamic range and detection limit of the sensor for detection of the L-DOPA were calculated to be 0.58 µA µM�1, 100 nM�85 µM and 25 nM, respectively. To compare the effect of the RGO in the modification process, the electrode was modified with the carbon paste electrode and the result shows the RGO has some admirable properties in the sensing strategy of the L-DOPA. © 2020 Elsevier B.V

Electrochemical determination of levodopa on a reduced graphene oxide paste electrode modified with a metal-organic framework

Developing easy-to-use sensors for monitoring of biomarkers which are related to human health is essential. Levodopa (L-DOPA) is a critical neurotransmitter that mainly uses for effective therapy of Parkinson's disease. This study introduces a novel reduced graphene oxide (RGO) paste electrode (PE), RGOPE, which is modified with a microporous metal-organic framework (MOF) as a sensing interface in the electrochemical determination of the L-DOPA. The electrochemical behavior of the modified RGOPE was studied by cyclic voltammetry (CV), square wave voltammetry (SWV), electrochemical impedance spectroscopy (EIS) and chronoamperometry techniques. The influence of parameters such as the scan rate and pH value on the peak current were investigated. Under the optimal condition, the modified RGOPE as a sensor presented a capability in highly sensitive sensing of the L-DOPA at a typical working potential of 0.56 V vs. Ag/AgCl. The sensitivity, linear dynamic range and detection limit of the sensor for detection of the L-DOPA were calculated to be 0.58 µA µM−1, 100 nM–85 µM and 25 nM, respectively. To compare the effect of the RGO in the modification process, the electrode was modified with the carbon paste electrode and the result shows the RGO has some admirable properties in the sensing strategy of the L-DOPA. © 2020 Elsevier B.V