Chemometric optimization of a SIA promethazine hydrochloride assay method

A sequential injection analysis (SIA) method for the assay of promethazine hydrochloride, based on its oxidation by acidified cerium(IV), was optimized. Three chemometric approaches were applied: (i) factorial design (3³ applied to surface plot and 2³ applied to effect factor) for screening the potential interacting variables, (ii) univariant for optimizing insignificantly interacting variables and (iii) simplex for optimizing potentially interacting variables. The optimum experimental conditions were 30 μl of 0.38 mol/l sulphuric acid, 30 μl of 3.99 × 10^− 3 mol/l cerium(IV), 20 μl of promethazine hydrochloride and 20 μl/s flow rate. The detection limit was 7.032 × 10^− 5 mol/l and the calibration curve was linear up to 1.563 mol/l with a correlation coefficient 0.9998, accuracy range of 89.0-101.5%, relative standard deviation 1.1% (n = 10) and sample frequency at least 20 samples/h. The method was applied to tablet form and validated with the British Pharmacopoeia method. The developed SIA method is fully automated, reproducible, sensitive, rapid and reagent-saving, and therefore suitable for routine control in tablets form.     

Study of (1−x)ZnAl2O4–xSiO2 spinel structures as microwave dielectric materials

Sol–gel method was used to synthesize zinc aluminate (ZnAl₂O₄) dispersed into silica matrix with different compositions of x. Morphological structure of (1?x)ZnAl₂O₄–xSiO₂ samples were investigated by field emission scanning electron microscope (FESEM) and X-ray diffractometer (XRD). The FESEM images showed spherical structures and agglomerated particles occurred inside the samples. XRD analysis indicated the cubic phase formation of the samples. The crystallite size, D was calculated and it was found that the crystallite size are slightly increased from 8 to 17 nm. FTIR spectra analysis shows that the water presence in the samples and also the presence of nitrate group. The dielectric properties have been measured, ε _r value was found to be around 13.0. The S₁₁ parameter analysis shows the samples was resonated at 2.40 GHz and gives different values of bandwidth for microstrip patch antenna application.     

A highly sensitive sensor of paracetamol based on zinc-layered hydroxide-<Emphasis Type="Italic">L</Emphasis>-phenylalanate-modified multiwalled carbon nanotube paste electrode

A new zinc-layered hydroxide-L-phenylalanate (ZLH-LP)-modified multiwalled carbon nanotube (MWCNT) was prepared as a new material of paste electrode for the detection of paracetamol (PCM) in 1.0?×?10^?1 M phosphate buffer solution and at pH 7.5. The electrochemical characterization of the MWCNTs/ZLH-LP paste electrode was characterized by square wave voltammetry, electrochemical impedance spectroscopy, and cyclic voltammetry while the morphology properties of the MWCNTs, ZLH-LP, and MWCNTs/ZLH-LP were investigated using transmission electron microscopy and scanning electron microscopy. Under optimized conditions, the MWCNTs/ZLH-LP paste electrode demonstrated an excellent electrocatalytic activity towards oxidation of PCM in the linear responses’ ranges from 7.0?×?10^?7 M to 1.0?×?10^?4 M (correlation coefficient, 0.996) with the limit of detection obtained at 8.3?×?10^?8 M. As a conclusion, the MWCNTs/ZLH-LP paste electrode revealed good repeatability, reproducibility, and stability, and was found to be applicable for use in pharmaceutical tablet samples.

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Models of the iron-only hydrogenase: structural studies of chelating diphosphine complexes [Fe2(CO)4(micro-pdt)(kappa2P,P'-diphosphine)

Six chelating diphosphine complexes, [Fe2(CO)4(micro-pdt)(kappa2P,P'-diphosphine)], have been crystallographically characterised allowing differences between basal-apical and dibasal conformations to be analysed.     

Environmental impact assessment of post illegal mining activities in Chini Lake with regards to natural radionuclides and heavy metals in water and sediment

Journal of Radioanalytical and Nuclear Chemistry - Comprehensive radiological survey and evaluation of heavy metal contamination were conducted in Chini Lake, which has been awarded a pristine...     

Backbending Phenomena in Even–Even $${}^{\boldsymbol{162{-}172}}$$ Hf Isotopes

Physics of Atomic Nuclei - This study probes the backbending phenomena in even–even $${}^{162{-}172}$$ Hf isotopes. Experimental ground-state rotational energies up to $$J^{\pi}=36^{+}$$...     

Kinetics of the reduction of tetrakis (2,2′-bipyridine)-μ-oxo-di-iron(III) by 1,3-benzenediol in aqueous acidic medium

The stoichiometry and kinetics of the reduction of Fe₂(III)(bpy)₄OCl₄ by 1,3-benzenediol have been investigated in aqueous hydrochloric acid medium. The reaction is first order in [oxidant] but zero order in [reductant]. There is no evidence for the formation of an intermediate complex of significant stability. The presence of NO₃ ⁻ or ClO₄ ⁻ had no effect on the rate of the reaction. Also, the reaction rate is not affected by the changes in the ionic strength and dielectric constant of the reaction media. A plausible mechanism involving an outer-sphere complex formed via an ion pair is proposed for the reaction.     

Use of granulated modified zeolite Y for the removal of inorganic arsenic and selenium species

Column studies were performed to evaluate the performance of modified zeolite-Y with ion Fe (zeolite-FeY) in removing As(III), As(V), Se(IV) and Se(VI) from groundwater. The removal capacities for zeolite-FeY was carried out on arsenic and selenium species in aqueous solution by co-precipitation technique with DBDTC-Pp complex in the pH range of 1.5–2.5 followed by the neutron activation analysis (NAA) using a TRIGA-MkII reactor with an average flux of 2.1 × 10¹² neutrons cm⁻² s⁻¹ and inductively coupled plasma-mass spectrometry (ICP-MS) technique as comparison. The accuracy between the results obtained from both techniques were compared and evaluated.