Voltammetric analysis of Cu (II), Cd (II) and Zn (II) complexes and their cyclic voltammetry with several cephalosporin antibiotics

Both osteryoung square wave voltammetry and cyclic voltammetry have been utilized to elucidate and confirm the possible complexation reaction that occur between the various cephalosporin antibiotics and either the toxic, non-essential metal ion, viz. Cd (II), or the essential but toxic (when their concentration exceeds certain level in serum) metal ions, viz. Cu (II) and Zn (II). Voltammetric measurements indicated the existence of 1:1 metal-to-ligand ratio (as in cephalexin and cephapirin complexes), 1:2 ratio (such as in cefamandole, cefuroxime and cefotaxime complexes) and 2:1 ratio in case of ceftazidime complexes. Adsorption behavior was evidenced for Cu (II)-cefuroxime or ceftazidime complexes as well as for those for Zn (II)-cephalexin or cephapirin. This phenomenon could be used for the determination of either the antibiotic or the metal ion using adsorptive stripping voltammetry. Detection limits down to 7x10(-10) M have been easily achieved.     

Ene reaction of the active XCN− and XCO group with ketones. A novel synthesis of X-oxo-α-amino- and X-oxo-oα-hydroxy-acids.

Thermal reaction of butyl N-(p-toluenesulphonyl)iminoacetate and diethyl mesoxalate with ketones leads to the derivatives of X-oxo-α-amino-acids and X-oxo-α-hydroxy -acids, respectively.     

Estimation of sample processing uncertainty for chlorpyrifos residue in cucumber

Sample processing is a very important component of uncertainty in analytical results. In order to have reliable results, the laboratory sample should be properly processed to obtain statistically homogenous matrix—before the representative test portions are withdrawn for analysis. The use of ¹⁴C-labeled compound is preferable because the analyte can be quantified without cleanup. The method is based on surface treatment of cucumber with ¹⁴C-chlorpyrifos, determination of ¹⁴C-chlorpyrifos activity in the replicate test portions of different size, and determination of the uncertainty of sample processing.     

The acid-base properties of Fast Grey R. A.

Summary The acid-base properties of Fast Grey R. A. have been studied with reference to the mode of chelation of the dye with different valent metals. The pK values of 3.83, 10.53 and 10.70 corresponding to the three steps of ionization of the free acid were evaluated by the aid of the relation between log [acid]/[salt] and p_H values obtained during the course of the potentiometric titration of the free acid with a free base.     

Determination of protein and trace elements in human milk using NAA and XFR techniques

The principal objective pursued in this study is to establish the base-line data on protein content and on the status of elemental composition in human milk from Sudanese subjects. The protein content was derived by multiplying the nitrogen content by a factor 6.25. The nitrogen was determined using a 14 MeV neutron generator. The median values for crude protein and the total dry matter found in this study were 1.23% (volume) and 104 g/l, respectively. Some minor and trace elements of biological significance namely, Cl, K, Ca, Mn, Fe, Cu, Zn, Cr, Co and Mo were determined using energy dispersive X-ray fluorescence spectrometry. The results obtained show good compatibility with the data reported by the WHO on elemental composition of human milk from different geographical regions.     

One-pot Multicomponent Synthesis,Spectroscopy, Crystal Structures and Theoretical Calculations of 3-Cyano-4-(4-hydroxy-3-methoxyphenyl)-6-phenyl-2(1H)-pyridinone and 3-Cyano-4-chlorophenyl-6-(4-tolyl)-2(1H)-pyridinone

Pyridinone derivatives are of great interest in medicinal chemistry where they were found to be potent to various diseases. Their metal complexes added more value to their applications. Here, we have synthesized two 2-pyridinone derivatives(3-cyano-4-(4-hydroxy-3-methoxyphenyl)-6-phenyl-2(1 H)-pyridinone and 3-cyano-4-chlorophenyl-6-(4-tolyl)-2(1 H)-pyridinone) using one-pot multicomponent system. They were well characterized using spectroscopic techniques like nuclear magnetic resonance(NMR-1 H 13 C), Fourier transform infrared(FT-IR) and UV/Vis spectroscopy. The final structures were determined using single-crystal X-ray diffraction technique which helps us to determine their geometries. Density functional theory(DFT) and time-dependent density functional theory(TD-DFT) with suitable basis-sets of calculations have correctly simulated these spectroscopic parameters. The intramolecular charge transfer(ICT) of both substrates has been discussed using natural bond orbital(NBO) technique. Molecular electrostatic potential(MEP) surfaces showed their reactive locations for intermolecular charge transfer. Compared to p-nitroaniline(pNA), both substrates were shown to have substantial molecular hyperpolarizability.     

A highly sensitive GC–MS method for simultaneous determination of anacardic acids in cashew (Anacardium occidentale) nut shell oil in the presence of other phenolic lipid derivatives

The commercial value of cashew nut shell liquid (CNSL) has become a cornerstone of the agrowaste industry. It is the by‐product of the cashew industry and has an 1/8 inch thickness of soft honeycomb structure. CNSL contains phenolic lipids with aliphatic chains such as anacardic acid, cardanol, cardol and methyl cardol, and their derivatives. The developed GC–MS method is rapid, accurate and selective using a selected derivatizing reagent, namely N‐methyl‐N‐(trimethylsilyl)‐trifluoroacetamide that was previously diluted 1:1% with anhydrous pyridine. The proposed GC–MS method was applied for the analysis of different CNSL samples. The results showed that all classes of CNSL compounds were detected. The four alkyl phenols were detected with their different alkyl sidechains without any interference. This method is also specified for the detection of fatty acids of saturated and unsaturated chains. Silylation did not cause any alteration in the chemical structure of CNSL compounds regardless of esterification action. Silylation is considered a safe derivatizing agent compatible with GC chromatography and specific for all volatile and nonvolatile polar and nonpolar CNSL compounds that could be detected in CNSL samples.