Acetylcholine (ACH) is one of the excitatory neurotransmitter in the human body. It is the most abundant neurotransmitter responsible for triggering the activation of postsynaptic neurons, leading to an excitatory response. ACH plays a crucial role in various physiological processes, including muscle contraction, autonomic nervous system regulation, and cognitive functions such as learning and memory. In this study, an electrochemical sensor was prepared based on WO3 nanorods modified glassy carbon electrode for the detection of ACH. The WO3 nanorods provided excellent properties for the electrochemical determination of ACH. The proposed sensor exhibited a wide linear detection range of (0.1 to 400.0 µM) and a low detection limit of 0.025 µM for ACH. These results demonstrate the sensor's high sensitivity in detecting this important neurotransmitter. In addition the developed sensor showed good ability for ACH determination in real samples. This study offers an innovative strategy for the electrochemical detection of ACH, showcasing the potential of nanomaterials in the development of advanced sensing technologies.

In this study, we report the electrochemical detection of sunset yellow (SY) at the surface of a carbon paste electrode (CPE) modified with CuCo2O4 nanorods (NRs) and an ionic liquid (IL). The electrochemical behavior of sunset yellow at the modified electrode was investigated using linear sweep voltammetry, differential pulse voltammetry and chrono­amperometry techniques. The CuCo2O4 NRs/IL/CPE sensor exhibited good performance and favorable electrochemical response for the electrochemical reaction of SY in a 0.1 M phosphate buffer solution at pH 7.0. The results showed a linear electrochemical response to SY within the concentration range of 0.2 to 160.0 μM, with a detection limit of 0.06 μM. In addition, The CuCo2O4 NRs/IL/CPE sensor demonstrated good ability for SY determination in real samples.

The current attempt was made to detect the amino acid homocysteine (HMC) using an electrochemical aptasensor. A high-specificity HMC aptamer was used to fabricate an Au nanostructured/carbon paste electrode (Au-NS/CPE). HMC at high blood concentration (hyperhomocysteinemia) can be associated with endothelial cell damage leading to blood vessel inflammation, thereby possibly resulting in atherogenesis leading to ischemic damage. Our proposed protocol was to selectively immobilize the aptamer on the gate electrode with a high affinity to the HMC. The absence of a clear alteration in the current due to common interferants (methionine (Met) and cysteine (Cys)) indicated the high specificity of the sensor. The aptasensor was successful in sensing HMC ranging between 0.1 and 30 μM, with a narrow limit of detection (LOD) as low as 0.03 μM.

Background and purpose: Methotrexate (MTX) is a widely used anti-cancer drug, but its overuse can lead to significant side effects. Therefore, it is very vital to design simple and sensitive analytical methods for its determi­na­tion. Experimental approach: In this work, an electrochemical sensor was prepared based on an ionic liquid (IL)/Ni-Co layered double hydroxide nanosheets (Ni-Co-LDH)-modified carbon paste electrode IL/Ni-Co-LDH/CPE. Cyclic voltammetry, differential pulse voltammetry, and chronoamperometry methods were applied to evaluate the performance of the designed sensor for MTX determination. Key results: The IL/Ni-Co-LDH/CPE sensor exhibits a linear relationship between the peak current of the differential pulse voltammetry and MTX concentrations in the linear dynamic range of 0.02 to 140.0 µM, with a detection limit of 0.006 µM. The IL/Ni-Co-LDH/CPE sensor exhibited relative standard deviation values between 1.7 to 3.7 % for recovery tests on real samples, indicating the precision of the method. Conclusion: The designed sensor with cost-effective and good performance could be valuable for therapeutic drug monitoring and clinical diagnostics.

Water pollution with phenolic compounds is a serious environmental issue that can pose a major threat to the water sources. This pollution can come from various agricultural and industrial activities. Phenolic compounds can have detrimental effects on both human health and the environment. Therefore, it is essential to develop and improve analytical methods for determination of these compounds in the water samples. In this work, the aim was to design and develop an electrochemical sensing platform for the determination of 2,4-dichlorophenol (2,4-DCP) in water samples. In this regard, a nanocomposite consisting of CoWO₄ nanoparticles (NPs) anchored on reduced graphene oxide nanosheets (rGO NSs) was prepared through a facile hydrothermal method. The formation of the CoWO₄/rGO nanocomposite was confirmed via different characterization techniques. Then, the prepared CoWO₄/rGO nanocomposite was used to modify the surface of a screen-printed carbon electrode (SPCE) for enhanced determination of 2,4-DCP. The good electrochemical response of the modified SPCE towards the oxidation of 2,4-DCP was observed by using cyclic voltammetry (CV) due to the good properties of CoWO₄ NPs and rGO NSs along with their synergistic effects. Under optimized conditions, the CoWO₄/rGO/SPCE sensor demonstrated a broad linear detection range (0.001 to 100.0 µM) and low limit of detection (LOD) (0.0007 µM) for 2,4-DCP determination. Also, the sensitivity of CoWO₄/rGO/SPCE for detecting 2,4-DCP was 0.3315 µA/µM. In addition, the good recoveries for determining spiked 2,4-DCP in the water samples at the surface of CoWO₄/rGO/SPCE showed its potential for determination of this compound in real samples.