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In this paper, a new isatin-Schiff base L1 was prepared via a simple reaction of isatin with 2-amino-3-hydroxypyridin. Subsequently, cerium(III)-Schiff base complex C1 was obtained through the reaction of the prepared Schiff base L1 with cerium chloride via a hydrothermal method. The prepared L1, as well as C1, were fully characterized using many spectroscopic techniques, such as mass spectra, elemental analysis, UV-vis, FT-IR, 1H-NMR, 13C-NMR, FE-SEM/EDX, and HR-TEM. A photoluminescence study (PL) was carried out for the prepared complex C1. The promising photoluminescence results revealed that C1 could be used for the detection of creatinine in different human biological samples as a selective optical biosensor. The results showed that C1 after excitation at 370 nm has a strong emission band at 560 nm. The calibration graph was obtained in a wide concentration range between 2.5 and 480 nM creatinine with limits of detection (LOD) and quantitation (LOQ) of 1.07 and 3.25 nM, respectively. In addition, the correlation coefficient (r2) was found to be 0.9890. The PL spectra indicate that C1 has high selectivity toward creatinine without interference from other different analytes and can be successfully used as an optical sensor for creatinine detection. The mechanism of quenching between the Ce(III) complex and creatinine was a dynamic type. The geometry of Schiff base L1 and its cerium(III) complex C1 was proven by using density functional theory (DFT). The energy of the LUMO and HOMO, energy gap, dipole moment and structure–activity relationship were determined and confirmed.

Worldwide, prostate cancer is considered to be one of the three most commonly occurring cancers amongst the male population. Clinically, early detection of diverse forms of cancer before they spread and become incurable plays an important role in treatment strategy. Therefore, the development of fast, accurate, sensitive, and low-cost analytical methodologies and techniques for the detection of cancer biomarkers is an attractive research area for scientists globally. Herein, a Schiff base ligand (A1) was prepared via the refluxing of 3-aminobenzoic acid with 1,2-phenylenediamine. After that, a nano Cu complex (N1) was synthesized by reacting A1 with copper chloride. The produced A1 and N1 were characterized using several techniques to determine their physicochemical properties. A density functional theory study was carried out to rationalize the experimental work and support the obtained results. Moreover, the nano Cu complex (N1) was used for the fabrication of a potentiometric membrane biosensor for the early detection of the prostate-specific antigen (PSA). The results reveal that the electrode displays a stable Nernstian response of 29.26 ± 0.87 mV per decade for PSA in a linear dynamic range of 5.0 pg mL-1-10.0 ng mL-1, in a pH range of 6.5-9.2, with a short response time of 25 ± 5 s. The lifetime was between 5-7 weeks under different storage conditions. The detection (LOD) and quantification (LOQ) limits were 0.098 and 0.297 pg mL-1, respectively. The presence of different interfering species on the potentiometric biosensor response against PSA was investigated. The sensing mechanism of N1 toward PSA and the applicability of the developed electrode for the screening and quantification of PSA in real serum samples were also studied.

The inhibition properties of two imidazol-1-ium bromide compounds, namely, 1-hexyl-1-methyl-1H-imidazol-1-ium bromide and 1-dodecyl-1-methyl-1H-imidazol-1-ium bromide on the carbon steel corrosion in 1.0 MHCl were estimated using mass loss, electrochemical, and theoretical studies. The new investigated compounds are easily prepared, low-cost, and effective corrosion inhibitors. It is found that these compounds act as excellent inhibitors and act as mixed-type inhibitors. EIS showed that the investigated compounds act by the creation of a protective film at the metal surface. The outcomes show that the inhibition effect of the investigated compounds is affected by the increasing concentration and the capability to produce micelles in an aqueous solution. The adsorption of imidazol-1-ium bromide derivatives is a physical type and agrees with Langmuir adsorption isotherm. SEM, AFM, and FTIR spectroscopy were used to study the morphology of the C-steel surface and the protecting film on the surface. The relationship between experimental results and theoretical calculations was confirmed. The results obtained open visions for the use of these surfactants as corrosion inhibitors. The data from different methods were in acceptable agreement.

Carbohydrazide functionalized cellulose (CH-MC) was prepared and characterized using some qualified techniques such as Scanning Electron Microscopy (SEM), Infra-Red (FT-IR), Elemental analysis (EA) and Thermogravimetric analysis(TGA) . The prepared CH-MC was employed for uptake of heavy metal ions such as, Hg2+and Cu2+ from different samples. Sorption parameters: such as pH, temperature, time of sorption and the concentration of sorbent were investigated to determine the best conditions for sorption. The kinetic of sorption agreed with the second-order model and the chemical adsorption is the rate-limiting step. In addition, the sorption isotherm experiments revealed that the best adequate with Langmuir model which the maximum adsorption capacities for Cu2+and Hg2+ metal ions on CH-MC are 43.3 and 64 mg/g, respectively. The real samples including Hg2+ and Cu2+were used for analytical applications on the present methodology and the observed data is promising.