Pyridine di‐carboxyamide derivative coupled chitosan (CTPO) is a new adsorbent prepared by coupling N2,N6‐dicarbamothioylpyridine‐2,6‐dicarboxamide with chitosan, which offers an excellent synergistic effect for the extraction of cadmium ions. FT‐IR, X‐ray diffraction, and thermal analysis techniques were used to characterize the modified new chitosan adsorbent. The Langmuir isotherm model accurately represents the adsorption effect with a maximum adsorption capacity of 307 mg/g. It was noted that the adsorption or up‐taking process of cadmium ions corresponded more closely to the pseudo‐second order instead of pseudo‐first order kinetic. The thermodynamic tools ΔS, ΔH and ΔG were also evaluated indicating endothermic and spontaneous adsorption process with a randomness increasing. The prepared new adsorbent is successfully used to extract cadmium ions from the actual leach liquor of Wadi Um‐Gheig ore sample.

Two spectrophotometric techniques that are straightforward, sensitive, accurate, and precise have been created and validated for the detection of a particular antidepressant drug, milnacipran HCl (MCN), in both pure and dosage forms. The method A was based on the reaction of MCN with p-dimethylaminobenzaldehyde (p-DMAB) in an acidic medium, to give a yellow colored Schiff’s base product that can be measured at a maximum wavelength of 400 nm. The concentration range of 60–300 μg/mL, with an excellent correlation coefficient (r2 = 0.9991) and with a relative standard deviation (RSD% = 2.0), complies with Beer’s law under ideal circumstances. The method B approach uses a cloud point extraction (CPE) methodology to measure the amount of the yellow color product utilizing Triton X-114 and cetyltrimethylammonium bromide (CTAB) as surfactants at a maximum wavelength of 410 nm. Beer’s law was obey in the concentration range of 0.2–4.0 μg mL−1, a correlation coefficient (r2 = 0.9995) and a relative standard deviation of (RSD% = 1.70). The best optimized reaction circumstances, including the type of solvent, reagent concentration, reaction time, and molar ratio. Calculations were made about the detection and quantification limits. No interference was seen with the frequently used excipients and additives. The proposed methods for determining MCN in its pharmaceutical formulations were effectively used, and the results for pure MCN and commercial tablets were in good agreement with those from the reported approach.

A low-cost, simple, and highly selective method was used for the assessment of total prostate specific antigen (tPSA) in the serum of prostate cancer patients. This method is based on quenching the intensity of luminescence displayed by the optical sensor Eu (TTA)3 phen/poly methylmethacrylate (PMMA) thin membrane or film upon adding different concentrations of tPSA. The luminescent optical sensor was synthesized and characterized through absorption, emission, scanning electron microscopy (SEM), and x-ray diffraction (XRD), and is tailored to present red luminescence at 614 nm upon excitation at 395 nm in water. The fabricated sensor fluorescence intensity is quenched in the presence of tPSA in aqueous media. The fluorescence resonance energy transfer (FRET) is the main mechanism by which the sensor performs. The sensor was successfully utilized to estimate tPSA in the serum of patients suffering prostate cancer in a time and cost effective way. The statistical results of the method were satisfactory with 0.0469 ng mL−1 as a detection limit and 0.99 as a correlation coefficient.

ABSTRACT. Mercury preconcentration in environmental samples and hair of occupational workers prior to spectrophotometric detection was described using a unique, eco-friendly, and quick ionic liquid-based cloud point extraction method. The discovered method used an ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate with Triton X-114 as an extracting phase in the presence of a new chelating agent 3-(2-hydroxy-5-ethoxycarbonylphen-1-ylazo)-1,2,4-triazole at pH 7.0 to separate mercury and measure the complex spectrophotometrically at wavelength 550 nm. The effects of several analytical factors on extraction performance were investigated. With a correlation coefficient of 0.9997. The calibration graph was linear in the range of 2.0-400 µg/L. The limit of detection and preconcentration factor, respectively, were 0.5 µg/L and 100. The relative standard deviation of 100 and 300 µg/L mercury (n = 10) was 1.5 and 2.2, respectively, indicating the precision and reliability of the new IL-CPE approach. The accuracy of the proposed approach confirmed through the certified reference materials analysis. The applicability of the established technique was demonstrated successfully by the estimation of trace mercury in environmental samples and hair of occupational workers.     KEY WORDS: Mercury, Ionic liquid-based cloud point extraction, Environmental and hair samples, Spectrophotometry   Bull. Chem. Soc. Ethiop. 2022, 36(4), 767-778.                                                         DOI: https://dx.doi.org/10.4314/bcse.v36i4.4