A voltammetric sensor for Sunset Yellow was fabricated by polymerizing L-cysteine on the surface of a glassy carbon electrode. The modified electrode was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The electrochemical behavior and kinetic parameters of Sunset Yellow in phosphate buffer solution (pH 6.6) were investigated by cyclic voltammetry and chronocoulometry using the proposed sensor, and results showed that the electrochemical response of Sunset Yellow was significantly improved. The peak current (differential pulse voltammetry) of Sunset Yellow linearly increased with the concentrations in the range of 8.0 Â 10 À9 -7.0 Â 10 À7 mol L À1 , and the minimum detectable concentration of Sunset Yellow was estimated to be 4.0 Â 10 À9 mol L À1 .Moreover, the linear relationship between the peak current and the concentration of Sunset Yellow in the presence of Lemon Yellow was 1.0 Â 10 À8 -5.0 Â 10 À7 mol L À1 , with a minimum detectable concentration of 6.0 Â 10 À9 mol L À1 . The reported electrochemical sensor was excellent for the determination of Sunset Yellow because of merits such as extreme simplicity, low cost, high sensitivity, good stability and reproducibility.

A novel voltammetric sensor for salbutamol is fabricated via self-assembly of gold nanoparticles on multiwalled carbon nanotubes and Nafion modified electrode. This sensor could improve the oxidation of salbutamol intensively. The oxidation process of salbutamol is studied and some dynamic parameters are calculated using various electrochemical techniques. Under the optimum conditions, the response peak currents have a linear relationship with the salbutamol concentrations in the range of 9.0 Â 10 À8 to 7.0 Â 10 À6 mol L À1 with a detectable limit of 5.0 Â 10 À8 mol L À1 . The proposed method is successfully applied to the determination of salbutamol in commercial pharmaceuticals and human serum samples with good accuracy and satisfactory recovery.

A novel voltammetric sensor, based on DNA immobilized on the surface of an ethylenediamine/polyglutamic (En/PGA) modified glassy carbon electrode (GCE), was constructed and used for determination of dihydromyricetin (DMY). The electrochemical behaviour of DMY at this sensor was investigated in pH 3.6 NaAc-HAc buffer solutions by cyclic voltammetry (CV) and differential pulse anodic voltammetry (DPV). The oxidation of DMY is an adsorption-controlled irreversible process. The oxidation mechanism was proposed and discussed. It was found that the modified electrode exhibited a linear voltammetric response for DMY in the range of 4.0 × 10(-8) mol L(-1) to 2 × 10(-6) mol L(-1), with a detection limit of 2 × 10(-8) mol L(-1). The method was also applied successfully to detect DMY in an ampelopsis sample with satisfactory results.

An ultrasensitive voltammetric sensor, a simply coated graphene-Nafion suspension on a glass carbon electrode surface, was fabricated and used to investigate the electrochemical behavior of theophylline as described in the present paper. The results indicated that this voltammetric sensor exhibited a special recognition capacity to determine theophylline as well as having high sensitivity due to the excellent characteristics of graphene and the adsorption action of Nafion for theophylline. Under the selected condition using differential pulse voltammetry, the response peak currents had a linear relationship with the theophylline concentrations in two ranges from 1.0 × 10 -8 -1.0 × 10 -6 and 2.0 × 10 -6 -3.0 × 10 -5 mol L -1 with a low detection limit of 6.0 × 10 -9 mol L

Monolithic luminescent glass‐ceramic (GC) embedded with fluoride‐based nanocrystals (NCs) has drawn much attention as it is stable and possesses long fluorescent lifetime, while only small partial of optically active ions could enter the fluoride NCs prepared by conventional crystallization process. In this work, YF3:Eu3+ embedded GCs have been controllably synthesized by Spark Plasma Sintering at a relatively low sintering temperature (960°C) within 10 minutes. The GC samples show typical sharp reddish‐orange emissions peaking at λ = 590 nm and 620 nm, which can be ascribed to the 5D0 → 7Fj transitions of Eu3+ located in the tetrahedral coordination sites of the YF3 NCs. Significantly, a small R/O ratio (photoluminescence intensity ratio of 5D0 → 7F2/5D0 → 7F1) suggests that majority of Eu3+ ions are well preserved in YF3 NCs, which is confirmed by the EDS and TEM results that highly crystallized YF3:Eu3+ NCs are homogeneously dispersed into the silica glass matrix without interfacial reaction. Hence, the lifetime of GC sample is prolonged to 6.8 ms These results demonstrate that Eu3+ could be well protected and resided in YF3 low phonon crystal by this method to fabricate GC composites with high optical performance.

A novel voltammetric sensor using multi-wall carbon nanotubes (MWNTs) coupled with Nafion modified glassy carbon electrode (GCE) was developed for the detection of methylparaben (MP). The sensor exhibited good electrocatalytic activity toward the oxidation of MP in the phosphate buffer solution (PBS, pH 6.5). It displayed good sensitivity, repeatability, reproducibility, and long-term stability. Under the optimized conditions, the anodic peak current was linear with the concentration of MP in the range of 3 Â 10 À6 mol L À1 to 1 Â 10 À4 mol L À1 . The detection limit was 1 Â 10 À6 mol L À1 . The proposed method was successfully applied to determine MP in cosmetics with satisfactory results.

DNA was attached on the surface of an ethylenedidamine/polyglutamic(En/PGA) modified glassy carbon electrode (GCE) to create a novel voltammetric sensor (DNA/En/PGA/GCE) for dopamine (DA). This modified electrode exhibited a linear voltammetric response for DA in the range from 1.0 10 À7 mol L À1 to 1 10 À5 mol L À1 , with a detection limit of 2 10 À8 mol L À1. The detection of DA was found to be unaffected by the presence of ascorbic acid, uric acid, serotonin and folic acid. The method proposed was applied to detect DA in pharmaceutical dosage and human blood serum with good satisfactory results.

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