Hisham S.M. Abd-Rabboh

Determination of Carrageenan in Food Products Using Potentiometric Polyion Sensors

Polymeric matrix tubular membrane sensors incorporating poly(vinyl chloride) matrix, o-nitrophenyloctylether (oNPOE) plasticizer and either dinonylnaphthalene sulfonate (DNNS) or tridodecylammonium chloride (TDMAC) ionophore are prepared and electrochemically evaluated for determination of carrageenan polyion. These sensors are used for monitoring potentiometric titration of carrageenan with protamine titrant. Carrageenan at the concentration levels of 0.2 ± 1.5% (m/m) in a variety of food products (e.g., cream, chocolate, caramel, ice cream, and salad dressing) are satisfactory determined. Results agree fairly well with nominal values are obtained and confirmed by recovery experiments of spiked samples. The method has several advantages over all previously reported methods in being more simple, accurate and applicable for routine analysis of real samples without prior treatment.

Bioactivities of Novel Metal Complexes Involving B Vitamins and Glycine

Abstract In this work twelve novel mixed ligand complexes were synthesized. The complexes were formed between a metal ion (Cu(II), Cd(II), Mn(II), Fe(III), Ni(II), Pb(II)) and vitamins (B 3 and B 9) as primary ligands, and glycine as secondary ligand. Melting points, conductivities, and magnetic susceptibilities of the synthesized complexes were determined and the complexes were subjected to elemental analyses. The presence of coordination water molecules in the complex was also supported by TG/DTG thermal analysis. Full elucidation of the molecular structures for the synthesized mixed ligand complexes were confirmed using detailed spectroscopic IR, 1H-, 13C-NMR, and XRD techniques. In addition, cytotoxic and antioxidant activities of the twelve synthesized solid complexes were tested to evaluate their bioactivities.

Platinum and vanadate Bioactive Complexes of Glycoside Naringin and Phenolates

Abstract Platinum(II) and vanadium(V) solid binary and ternary complexes involving naringin, a flavanone glycoside in found in grapefruit, and some phenolic acids were synthesized and fully characterized using detailed structural and spectroscopic analysis techniques such as IR, NMR, and SEM techniques. The magnetic susceptibility results as well line drawings of the platinum and vanadium complexes showed four-coordinate square-planar and remarkable low-spin diamagnetic species; which is in agreement with the structures proposed. The cytotoxic activities of the binary and ternary vanadium and platinum metal complexes of phenolic acids and naringin were tested and evaluated against HepG2 (human hepatocellular carcinoma), MCF-7 (human breast adenocarcinoma), and HCT116 (human colorectal carcinoma) tumor cell lines. Also, their antioxidant activities were examined by free radical scavenging assay. The relationship between the chemical structure of the synthesized complexes and their biological influence was studied and evaluated.

A novel spectrophotometric method for determination of cyanide using cobalt (II) phthalocyanine tetracarboxylate as a chromogen

Cobalt (II) phthalocyanine tetracarboxylate [Co (II)Pc-COOH] has been prepared and used in aqueous solutions as a novel chromogenic reagent for the spectrophotometric determination of cyanide ion. The method is based on measuring the increase in the intensity of the monomer peak in the reagent absorbance at 682 nm due to the formation of a 1 : 2 [Co (II)Pc-COOH] : [CN] complex. The complex exhibits a molar absorptivity (ε) of 7.7 × 104 L mol−1 cm−1 and a formation constant (Kf ) of 5.4 ± 0.01 × 106 at 25 ± 0.1°C. Beers law is obeyed over the concentration range 0.15–15 µg mL−1 (5.8 × 10−6–5.8 × 10−4 M) of cyanide ion, the detection limit is 20 ng mL−1 (7.7 × 10−7 M) the relative standard deviation is ±0.7% (n = 6) and the method accuracy is 98.6 ± 0.9%. Interference by most common ions is negligible, except that by sulphite. The proposed method is used for determining cyanide concentration in gold, silver and chromium electroplating wastewater bath solutions after a prior distillation with 1 : 1 H2SO4 and collection of the volatile cyanide in 1 M NaOH solution containing lead carbonate as recommended by ASTM, USEPA, ISO and APAHE separation procedures. The results agree fairly well with potentiometric data obtained using the solid state cyanide ion selective electrode.

Norleucine metal complexes: comments on their equilibrium constants data

Abstract This discussion article summarizes all protonation and stability constants data found in the literature for nonprotein l-norleucine amino acid and its metal complexes. The results of approximately 18 published articles discussing the protonation and complexation equilibria of l-norleucine using different techniques and software were presented to comprehend the data on the grounds of modern aspects of l-norleucine complex chemistry.