Remarkably Enhanced Luminol/H2O2 Chemiluminescence with Excellent Peroxidase-like Activity of FeCoNi-based Metal-Organic Xerogels for the Sensitive Detection of Dopamine.

Metal-organic gels (MOGs) are a category of metal-organic smart soft materials with large specific surface areas, loose porous structures, and open metal active sites. In this work, trimetallic Fe(III)Co(II)Ni(II)-based MOGs (FeCoNi-MOGs) were synthesized at room temperature via a simple and mild one-step procedure. Fe3+, Co2+, and Ni2+ were the three central metal ions in it, while 1,3,5-benzenetricarboxylic acid (H3BTC) served as the ligand. The solvent enclosed in it was then removed by freeze-drying to get the corresponding metal-organic xerogels (MOXs). The as-prepared FeCoNi-MOXs have excellent peroxidase-like activity and can significantly enhance luminol/H2O2 chemiluminescence (CL) by more than 3000 times, which is very effective compared with other reported MOXs. Based on the inhibitory effect of dopamine on the CL of the FeCoNi-MOXs/luminol/H2O2 system, a simple, rapid, sensitive, and selective CL method for dopamine detection was established with a linear range of 5-1000 nM and a limit of detection of 2.9 nM (LOD, S/N = 3). Furthermore, it has been effectively used for the quantitative measurement of dopamine in dopamine injections and human serum samples, with a recovery rate of 99.5-109.1%. This research brings up prospects for the application of MOXs with peroxidase-like activity in CL.

Sonochemiluminescence Using Apertureless USB Piezoelectric Ultrasonic Transducer and Its Applications for the Detection of Hydrogen Peroxide, Glucose, and Glucose Oxidase Activity.

The mesh-type USB piezoelectric ultrasonic transducer (USB-PUT) used in household humidifiers and inhalation therapy devices is very cheap, small, and energy saving. It holds great promise for sonochemistry. However, the microtapered apertures in the center of the stainless steel substrate of mesh-type USB-PUT can lead to rapid atomization of solution, leakage of solutions containing surfactants and organic solvent through the apertures, and high background emission. Herein, we design a new type of USB-PUT by replacing the meshed stainless steel substrate with an apertureless stainless steel substrate. We have found that this apertureless USB-PUT can not only induce intense sonochemiluminescence (SCL) but can also enable sensitive luminol SCL detection of hydrogen peroxide which is practically impossible using mesh-type PUT because of the strong background SCL emission. By using this apertureless device to induce SCL and using smart phone as a detector, a visual hydrogen peroxide SCL detection method with a linear range of 0.5-50 µM and a detection limit of 0.32 µM is established. Moreover, the device can achieve the detection of glucose oxidase (GOD) activity and glucose by enzymatic conversion of glucose to hydrogen peroxide. The linear range of GOD detection is 1-200U/L with a detection limit of 0.86 U/L. The linear range of glucose detection is 0.5-70 µM with a detection limit of 0.43 µM. The cheap (a few dollars) and user-friendly apertureless USB-PUT is promising for sonochemistry applications and chemical education.

Wireless single-electrode electrochemiluminescence device based on wireless reverse charging or on-the-go USB transmission for multiplex analysis.

A wireless electrochemiluminescence (ECL) device employing the wireless reverse charging function or on-the-go (OTG) USB transmission function of smartphones is designed. It was coupled with a multi-channel single-electrode electrochemical system based on the resistance-induced potential difference for multiple ECL analyses using a smartphone as the detector.

Potentiometric sensors for the determination of pharmaceutical drugs.

Potentiometric sensors based on ion-selective membrane electrodes have continued to get great attention from the scientific community. These sensors have been employed in several applications including medicine, forensic analysis, environmental assessment, industry, agriculture, and pharmaceutical drug analysis. Indeed, these sensors possess several advantages, for example, simple design, fabrication, and manipulation, rapid response time, good selectivity, applicability to colored and turbid solutions, and possible interfacing with automated and computerized systems. On the other hand, therapeutic drug monitoring and the detection of pharmaceutical drugs in their pharmaceutical formulations and biological matrices are highly significant from a medical point of view, especially for drugs with a narrow therapeutic index, such as anticancer drugs, which can cause fatal side effects for patients. Interestingly, potentiometric sensors have been broadly employed as one of the most important electrochemical approaches for pharmaceutical drug analysis. Moreover, the breakthroughs in potentiometric sensors based on ion-selective electrodes (ISEs) make them superior to the other reported methods for pharmaceutical drug analysis in terms of many performance parameters, such as sensitivity, selectivity, low detection limit, and low cost. In this review, we try to offer a summary prologue to the applicability and merits of potentiometric sensors that have been employed for pharmaceutical drug analysis while emphasizing their application for the assay of pharmaceutical drugs in their dosage forms and the in-vivo assay of pharmaceutical drugs in different biological samples such as milk, water, plasma, and urine.