Binder-free and efficient voltammetric sensor based on Zn-Ca2CuO3 nanoparticles for simultaneous determination of amlodipine, acetaminophen, and ascorbic acid in hypertension patients.

Amlodipine (AM) is a long active calcium channel blocker used to relax blood vessels by preventing calcium ion transport into the vascular walls and its supporting molecules acetaminophen (AP) and ascorbic acid (AA) are recommended for hypertension control and prevention. Considering their therapeutic importance and potential side effects due to over dosage, we have fabricated a sensor for individual and simultaneous determination of AA, AP, and AM in pharmaceuticals and human urine using novel Zn-doped Ca2CuO3 nanoparticles modified glassy carbon electrode (GCE). Optimally doped Ca2CuO3 (2.5 wt% Zn at Cu site) enhanced the detection of target molecules over much wider concentration ranges of 50 to 3130 µM for AA, 0.25 to 417 µM for AP, and 0.8 to 354 µM for AM with the corresponding lowest detection limits of 14 µM, 0.05 µM, and 0.07 µM, respectively. Furthermore, the Zn-Ca2CuO3/GCE exhibited excellent selectivity and high sensitivity even in the presence of several potential interfering agents. The usefulness of the developed electrode was tested using an amlodipine besylate tablet and urine samples of seven hypertension patients under medication. The results confirmed the presence of a significant amount of AP and AM in six patients' urine samples indicating that the personalized medication is essential and the quantum of medication need to be fixed by knowing the excess medicines excreted through urine. Thus, the Zn-Ca2CuO3/GCE with a high recovery percentage and good sensitivity shall be useful in the pharmaceutical and biomedical sectors.

Quick and accurate determination of hazardous phenolic compounds using CaCu2O3 nanorods based electrochemical sensor.

In the present work, we report the fabrication of a novel electrochemical sensor based on nanostructured CaCu2O3 as electrode material for the simultaneous determination of 2-Aminophenol (o-AP), 2-Chlorophenol (o-CP) and 2-Nitrophenol (o-NP). Nanorods-shaped CaCu2O3 have been synthesized by chemical precipitation method and characterized by powder X-ray diffraction (XRD), X-ray photo-electron microscopy (XPS), field emission electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). Glassy carbon electrodes (3 mm diameter) have been modified using CaCu2O3 nanorods by drop-casting method. Cyclic voltammetry (CV) studies at CaCu2O3/GCE exhibited excellent electrochemical behaviours towards the oxidation of 2-AP, 2-CP and 2-NP at different potentials well separated from each other. The CaCu2O3/GCE displayed the lowest detection limits of 5.74 nM (0.626 ppb), 1.38 nM (0.177 ppb) and 1.03 nM (0.143 ppb) for 2-AP, 2-CP and 2-NP respectively over wide measurable linear ranges of 175 nM-68 µM (2-AP), 50 nM-90 µM (2-CP) and 25 nM-32 µM (2-NP). Cyclic stability studies showed a loss of 7%, 13% and 14% from initial current responses after conducting 100 cycles of CV for 2-AP, 2-CP and 2-NP in PBS (pH 7.0) which indicated the excellent stability of the fabricated electrode. Reproducibility studies of six different CaCu2O3/GCEs exhibited good recoveries in the order of 3.23% (2-AP), 3.54% (2-CP) and 2.46% (2-NP) respectively. The fabricated electrode with excellent sensitivity, stability and reproducibility has been successfully applied for the determination of 2-AP, 2-CP and 2-NP simultaneously in tap water and agricultural water samples. Selectivity studies carried out on CaCu2O3/GCE revealed its ability to detect 4-aminophenol and 4-nitorphenol at different oxidation potentials. High performance liquid chromatography (HPLC) studies have been carried out to validate the practical utility of the fabricated sensor.

Precise and quick detection of ascorbic acid and eugenol in fruits, pharmaceuticals and medicinal herbs using hydroxyapatite-titanium dioxide nanocomposite-based electrode.

Ascorbic acid (AA) and eugenol (EUG) are well-known antioxidants found in several fruits, spices and herbs. In particular, the EUG, one of the major phytocompounds present in clove, acts as pro-oxidant or anti-oxidant depending on its concentration. Considering the medical importance of AA and EUG and its extensive usage in the form of food and medicine, we have developed a voltammetric sensor based on hydroxyapatite-TiO2 composite modified GCE for their selective and simultaneous determination over very wide linear range of 2.78-2490 µM for AA and 1.4-78 µM for EUG with the LODs of 63.3 nM and 94 nM respectively. Practical applicability of the prepared electrode has been demonstrated by detecting AA and EUG in lemon juice, vitamin tablet, clove oil and Kabasura Kudineer, an herbal decoction used as an immunity booster against number of diseases including Covid-19. The proposed HAP-TiO2/GCE shall be useful for food and pharmaceutical industries.