Jie Zhao

The design of carbonate-selective electrodes with high sensitivity, stability, and selectivity holds significant potential for applications in marine environmental monitoring. In this study, a novel pine-leaf porous structure carbonate ion-selective electrode was prepared with a solid contact layer of silver nanoparticles/polyaniline (AgNPs@PANI) using a two-step electrochemical method involving electropolymerized PANI and electrodeposited AgNPs. The novel structure provides additional charge transport paths and a larger contact area for carbonate ions passing through the selective membrane, thereby enhancing the membrane's carbonate-responsive performance. The results indicate that the GE/AgNPs@PANI/CO₃ ²⁻-ISE demonstrates a near-Nernst response (−29.5 ± 0.2 mV per decade) to carbonate ions over a wide concentration range (10⁻¹–10⁻⁶ M) as well as a low carbonate detection limit (1.15 × 10⁻⁷ M), with excellent performance in terms of response speed (5.5 s), reversibility (1.35 mV), long-term potential stability (0.17 mV h⁻¹), and selectivity. The developed electrode was applied to the detection of carbonate in real seawater using the standard addition method, and the average recovery was found to be 95–105%. Meanwhile, the results of carbonate ion detection in real samples using this electrode were largely consistent with those obtained by potentiometric titration, demonstrating significant practicality in marine chemistry research.

The exploitation of ion-selective membranes with high power density and low resistance is crucial for harvesting osmotic energy in natural environments. However, the exploration of membranes that synergistically satisfy the demands of these properties in osmotic energy conversion remains largely unresolved. Herein, we demonstrate the application of a negative surface-modified 3D porous poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonate) (PEDOT:PSS) hydrogel for osmotic membranes, which effectively improved their deficiencies. Experiments, validation and simulations confirmed that the hydrogel membranes have remarkable space charge-modulated ion transport properties. Consequently, an impressive power output of 6.26 W m⁻² can be realized, which exceeds the prevailing commercial standard (5 W m⁻²). Meanwhile, five device units were connected in series to charge a supercapacitor which exhibited an impressive selectivity rate of 95.6%, coupled with an electrochemical energy conversion efficiency of approximately 45.8%. This research paves a new avenue towards the application of hydrogels in ultra-high performance osmotic membranes.

An electrochemical strategy for the simultaneous detection of DA and EP with high sensitivity by cyclic square wave voltammetry using a modified open source potentiostat.

The oil pipeline network system (OPNS) is an essential part of the critical infrastructure networks (CINs), and is vulnerable to earthquakes. Assessing and enhancing the resilience of the OPNS can improve its capability to cope with earthquakes or to recover the system’s performance quickly after the disturbance. This study defines the concept of OPNS resilience in the resistive ability, the adaptive ability, and the recovery ability. Then, the quantitative resilience assessment model is established considering the earthquake intensities, the role of safety barriers, the time-variant reliability, and the importance coefficient of each subsystem via a Monte Carlo simulation. Combining the model with GIS technology, a new methodology to evaluate OPNS resilience is proposed, and the resilience partition technology platform is developed, which can visualize the results of the resilience assessment. Finally, a case study is implemented to demonstrate the developed methodology, and a discussion is provided to identify the sensitive variables. The proposed resilience methodology can provide a framework for the probabilistic resilience assessment of OPNS, and could be expanded to other lifeline network systems.

On-site screening of copper ions in body fluid plays a critical role in monitoring human health, especially in heavy pollution areas. In this study, we have developed a hybrid 3D printed integrated microdevice for the determination of copper ions in human body fluids. A fixed and low volume of sample was detected by using the integrated microdevice without any preprocessing. The hybrid channel enables sample uniform mixing and quantitative dilution with buffer solution by inducing the “horseshoe vortex” phenomenon. The electrolytic microcell based on the flow detection system shows a more effective copper ion reaction ratio and, as a result, a better sensitivity. The simulation of the finite element method (FEM) determined the relevant optimum parameters of the hybrid channel and the microcell. The design, fabrication, and detection procedure of the integrated microdevice are here illustrated. The microdevice presented superior detection properties towards copper ions. The calibration curves covered two linear ranges varying from 20 to 100 ppb and 100 to 400 ppb, respectively. The limit of detection was estimated to be 15 ppb (S/N = 3). The relative standard deviation of the peak current measurements was 2.26%. The designed microdevice was further applied to detect copper ions in practical samples (calf serum sample and synthetic human urine sample) using a standard addition method, and the average recovery was found to be 95–104%. The performance of copper ion detection with the integrated microdevice was consistent with that of the inductively coupled plasma mass spectrometry (ICP-MS) in the same practical samples, demonstrating significant practicality in the test of body fluidics. The portable integrated microdevice is an excellent choice for on-site detection and has a promising prospect in the point-of-care testing (POCT) applications. Graphical abstract

A graphene-based electrochemical flow analysis device for simultaneous determination of dopamine, 5-hydroxytryptamine, and melatonin.