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As an abundant, inexpensive, and renewable biomass raw material, taro [Colocasia esculenta (L.) Schott] stalks were employed as a simple biochar template due to their porous structure. A composite composed of gold microsphere and taro stalk derived porous carbon (Au-MS@TSPC) was used to construct an electrochemical sensor for the sensitive determination of rutin. Under the optimized conditions, the sensor exhibited a wide linear range from 0.12 to 10.0 μmol·L−1 with a detection limit of 0.0265 μmol·L−1. The sensor demonstrated good selectivity and was applied to the determination of rutin in human serum with recoveries from 94.0% to 105.8%. The fabrication of Au-MS@TSPC in this study provides a promising approach for the subsequent utilization of taro stalks. [ABSTRACT FROM AUTHOR]

As a typical plant hormone, indole‐3‐acetic acid (IAA) can regulate the biological activities including division, growth and differentiation of plant cells. In this paper, a MXene and multi‐walled carbon nanotubes composite was prepared by self‐assembly procedure, which was modified on screen‐printed electrode (SPE) to construct a wireless portable electrochemical sensor. Electrochemical investigations of IAA were studied by cyclic voltammetry and an irreversible oxidation process could be observed. The excellent electroanalytical method of IAA was realized on the modified SPE with the detection range as 0.05–125.0 μmol/L and the detection limit as 16.7 nmol/L. The sensor was used for IAA content analysis in different part of pea seedlings with satisfactory results. [ABSTRACT FROM AUTHOR]

Lead ion causes heavy metal pollution, which can cause serious damage to the ecological environment and human health. In this paper, a simple and sensitive photoelectrochemical method was designed for lead ion detection by using ZnO nanorods as the photoactive substrate and complementary strand aptamers as target recognition element. ZnO nanorods with favorable stability and photoelectric activity can provide a biocompatible microenvironment for aptamer loading. In the presence of lead ion, it would combine with the recognition aptamer S2 by competing with the aptamer S1, which led to changes in surface structure and charge density before and after the recognition of target, causing regular response of photocurrent. The developed method under optimized experimental conditions presented high sensitivity and good selectivity for lead ion detection with low detection limit as 3.5 × 10−11 mol/L. In addition, the proposed strategy was also further applied to the detection of lake water sample, which provided reliable experimental support and basis for further exploration and establishment of complex aptamer recognition and detection system. [ABSTRACT FROM AUTHOR]

In this paper, an electrochemical aptamer sensor was proposed for the highly sensitive detection of mercury ion (Hg2+). Carbon nanofiber (CNF) was prepared by electrospinning and high‐temperature carbonization, which was used for the loading of platinum nanoparticles (PtNPs) by the hydrothermal method. The Pt@CNF nanocomposite was modified on the surface of carbon ionic liquid electrode (CILE) to obtain Pt@CNF/CILE, which was further decorated by gold nanoparticles (AuNPs) through electrodeposition to get Au/Pt@CNF/CILE. Self‐assembling of the thiol‐based aptamer was further realized by the formation of Au‐S bond to get an electrochemical aptamer sensor (Aptamer/Au/Pt@CNF/CILE). Due to the specific binding of aptamer probe to Hg2+ with the formation of T‐Hg2+‐T structure, a highly sensitive quantitative detection of Hg2+ could be achieved by recording the changes of current signal after reacting with Hg2+ within the concentration range from 1.0 × 10−15 mol/L to 1.0 × 10−6 mol/L and the detection limit of 3.33 × 10−16 mol/L (3σ). Real water samples were successfully analyzed by this method. [ABSTRACT FROM AUTHOR]

In this article, an electrochemical sensor based on a gold nanocage (AuNC)‐modified carbon ionic liquid electrode (CILE) was fabricated and applied to the sensitive rutin determination. The presence of AuNCs on the electrode surface greatly improved the electrochemical performance of the working electrode due to its specific microstructure and high metal conductivity. Electrochemical behavior of rutin on AuNCs/CILE was studied using cyclic voltammetry and differential pulse voltammetry with the related electrochemical parameters calculated. Under the optimal experimental conditions, the oxidation peak current of rutin and its concentration had good linear relationship in the range from 4.0 × 10−9 to 7.0 × 10−4 mol/L with a low detection limit of 1.33 × 10−9 mol/L (3σ). This fabricated AuNCs/CILE was applied to direct detection of the rutin concentration in drug samples with satisfactory results, showing the real application of AuNCs in the field of chemically modified electrodes. [ABSTRACT FROM AUTHOR]

A simple and sensitive electrochemical sensor was developed for the detection of tracelevels of luteolin. The sensoris based on a novel type of chemically modified electrode: gold nanocage (AuNCs)-modified carbon ionic liquid electrode (CILE). To construct this electrochemical sensing platform for luteolin, CILE is initially prepared by using 1-hexylpyridinium hexafluorophosphate as the binder and then AuNCs are coated on the surface of CILE to fabricate AuNCs-modified CILE (AuNCs/CILE). Electrochemical studies have shown that AuNCs/CILE can exhibit enhanced electrocatalytic activity toward the redox reaction of luteolin, therefore, the redox peak current of luteolin can be greatly improved, resulting in the high sensitivity of the developed sensor. Under the optimal conditions, the oxidation peak currents of the sensor increase linearly with an increase in the luteolin concentration in a range from 1 to 1000 nM with a detection limit of 0.4 nM, which is lower than those of most reported electrochemical luteolin sensors. Moreover, the reproducibility, precision, selectivity, and stability of this sensor are excellent. Finally, the sensing system was applied to the analysis of luteolin-spiked drug samples and the recovery in all cases was 95.0–96.7%, indicating the potential application of this simple, facile, and sensitive sensing system in pharmaceutical analysis. [ABSTRACT FROM AUTHOR]

In this paper cobalt oxide (Co 3 O 4) nanoparticles were mixed with polyacrylonitrile to prepare Co 3 O 4 doped carbon nanofiber (CNF) composite by electrospinning and carbonization, which was further used to modify on carbon ionic liquid electrode (CILE). Hemoglobin (Hb) was immobilized on Co 3 O 4 –CNF/CILE surface with Nafion acted as the protective film to fabricate an electrochemical biosensor (Nafion/Hb/Co 3 O 4 –CNF/CILE). Electrochemical behavior of Hb on the electrode was investigated with a pair of quasi-reversible redox peak appeared on cyclic voltammogram and electrochemical parameters were calculated. Moreover, this biosensor had good analytical capabilities for electrocatalytic reduction of different substrates including trichloroacetic acid, potassium bromate and sodium nitrite with wider detection range from 40.0 to 260.0 mmol L−1, 0.1 to 48.0 mmol L−1 and 1.0 to 12.0 mmol L−1 by cyclic voltammetry, respectively. The proposed method showed excellent anti-interferences ability with good selectivity and was successful used for quantitative detection of real samples, which displayed the potential applications to develop into a new analytical device. Image 1 • A cobalt oxide nanoparticle doped carbon nanofiber composite was synthesized for the design of electrochemical biosensor. • Direct electrochemical behaviors of hemoglobin were realized. • Electrocatalytic reduction to various substrates were investigated. [ABSTRACT FROM AUTHOR]

Typical synthesis procedures and recent developments of BP and BP-related composites. [Display omitted] • Typical synthesis procedures and natural property advantages of BP are summarized. • Recent applications in electrochemistry and bioelectrochemistry are reviewed. • Major limitations and future developments are discussed. Due to the specific advantages including excellent interface activity, high photoelectric properties, fast electron transfer rate, good conductivity and biocompatibility, black phosphorus (BP) can be used in the various fields. In this review the new applications of BP and its related composites in the fields of electrochemistry and bioelectrochemistry had been summarized. The discussions included different kinds of batteries, supercapacitors, optoelectronic devices, electrochemical sensors and biosensors. Lastly the future challenges of BP-based composites in these fields are predicated. [ABSTRACT FROM AUTHOR]