Spectroscopic and electrochemical characterization of some Schiff base metal complexes containing benzoin moiety.

The ligation behavior of bis-benzoin ethylenediamine (B2ED) and benzoin thiosemicarbazone (BTS) Schiff bases towards Ru(3+), Rh(3+), Pd(2+), Ni(2+) and Cu(2+) were determined. The bond length of M-N and spectrochemical parameters (10Dq, β, B and LFSE) of the complexes were evaluated. The redox characteristics of selected complexes were explored by cyclic voltammetry (CV) at Pt working electrode in non aqueous solvents.

Analysis of spironolactone residues in industrial wastewater and in drug formulations by cathodic stripping voltammetry.

The redox behavior of spironolactone (SP) drug in Britton-Robinson (BR) buffer of pH 2-11 was investigated by differential pulse cathodic stripping voltammetry (DPCSV) and cyclic voltammetry (CV) at hanging mercury dropping electrode (HMDE). At pH 9-10.5, the DPCSV of SP drug showed two cathodic peaks at -1.

Analysis of some selected catechins and caffeine in green tea by high performance liquid chromatography.

Green tea seems to have a positive impact on health due to the catechins-found as flavanols. Thus, the present study was aimed to develop a low cost reversed phase high performance liquid chromatographic (HPLC) method for simultaneous determination of flavanol contents, namely catechin (C), epicatechin (EC), epigallocatechin (EGC), epicatechin 3-gallate (ECG) and epigallocatechin 3-gallate (EGCG) and caffeine in 29 commercial green tea samples available in a Saudi Arabian local market. A C-18 reversed-phase column, acetonitrile-trifluoroacetic acid as a mobile phase, coupled with UV detector at 205 nm, was successfully used for precise analysis of the tested analytes in boiled water of digested tea leaves.

Spectrofluorometric determination and chemical speciation of trace concentrations of chromium (III & VI) species in water using the ion pairing reagent tetraphenyl-phosphonium bromide.

A highly selective, and low cost extractive spectrofluorometric method has been developed for determination of trace concentrations of chromium (III & VI) in water samples using the fluorescent reagent tetraphenylphosphonium bromide (TPP(+) · Br(-)). The method was based upon solvent extraction of the produced ion associate [TPP(+) · CrO(3)Cl(-)] of TPP(+) · Br(-) and halochromate in aqueous HCl and measuring the fluorescence quenching of TPP(+) · Br(-) in chloroform at λ(ex/em)=242/305 nm. The fluorescence intensity of TPP(+)Br(-) decreased linearly on increasing the chromium (VI) concentration in the range of 1-114 μg L(-1).

Part 1. Spectrophotometric determination of trace mercury (II) in dental-unit wastewater and fertilizer samples using the novel reagent 6-hydroxy-3-(2-oxoindolin-3-ylideneamino)-2-thioxo-2H-1,3-thiazin-4(3H)-one and the dual-wavelength beta-correction spectrophotometry.

A simple and low cost method was developed and validated for the determination of trace mercury (II) ions in dental-unit wastewater and fertilizer samples. The method was based upon the reaction of mercury (II) ions with the novel reagent 6-hydroxy-3-(2-oxoindolin-3-ylideneamino)-2-thioxo-2H-1,3-thiazin-4(3H)-one, the formed complex shows an absorption maximum at 505 nm (lambda(max)) in Britton-Robinson (B-R) buffer (pH 4-6).The corrected absorbance of the formed complex at lambda(max) was obtained employing beta-correction spectrophotometric method.