Current Analytical Chemistry - Volume 10, Issue 4, 2014

The ICP-AES technique was developed for rhenium determination in the range of 0.00002 - 0.05 % in copper and molybdenum ores along with their concentrates. The sample pretreatment method by sintering with magnesium oxide and oxidizing agents was offered for analysis; optimum conditions for samples digestion were established. These conditions enabled to pass rhenium into solution with no losses. Matrix influenc Read More

Ornidazole is an antibacterial drug active compound. A glassy carbon electrode (GCE) was modified with an electropolymerized film of p-aminobenzene sulfonic acid (p-ABSA) in pH 7.0 phosphate buffer solution (PBS). The electrochemical properties of the polymer film were studied using cyclic voltammetry (CV) and different pulse voltammetry (DPV) techniques. The polymer film-modified electrode was used to elect Read More

This work presents the development and validation of a capillary zone electrophoresis method for calcium ions release quantitation from composite biomaterials with potential application in bone tissue engineering. Calcium ions quantitation was made using a fused silica capillary (40 cm, 75 m ID) and background electrolyte containing 5 mM imidazole, 6 mM α-hydroxyisobutyric acid, 1 mM 1,4,7,10,13,16-hexaoxacyclo-octadeca Read More

A selective and sensitive cloud point extraction procedure for the preconcentration of trace amounts of gold prior to their determination by flame atomic absorption spectrometry has been developed. The cloud point extraction method is based on the formation AuI3 and then entrapped in non-ionic surfactant Triton X-114. The main factors affecting cloud point extraction efficiency, such as pH of sample solution, concentrati Read More

Graphene, a monolayer of carbon atoms densely packed into a two-dimensional honeycomb crystal lattice, has recently attracted much attention. It possesses an ultrahigh specific surface area, and thus has great potentials for the use as sorbent materials. In this article, we have developed a new method for the preconcentration and determination of trace amounts of cadmium (Cd) prior to its determination by flame atomic a Read More

In an attempt to discriminate and identify several bacterial species, headspace air samples above a series of bacterial cultures were interrogated using a TD-GC/MS system. Three microorganism strains with relatively low pathogenic character – Escherichia coli, Bacillus subtilis and Staphylococcus aureus – were investigated during a period of 72 hours from the inoculation. Air samples with a volume of 1 L each were Read More

An improved procedure is presented to determine Pb(II) and Cu(II) in gasoline using a mercury film electrode generated in situ. The method is based on the reduction of the metal ions at adequate potentials on the glassy carbon electrode, in whose optimized microemulsion medium composition, the ions can be determined directly and simultaneously by differential pulse anodic stripping voltammetry. Good results we Read More

The influence of different protic and aprotic solvents on the conductometric titrations of cerium(III) with EDTA has been studied. The results are explained for mixed solvent systems using 1,4-dioxane (DA), acetonitrile (ACN), Dimethylsulphoxide (DMSO), N,N’-dimethylformamide (DMF), Tetrahydrofuran (THF) and Methanol (MA) as cosolvents. End points of conductometric titrations improved in presence of 1,4 dioxane as Read More

A novel sorbent was synthesized by modification of graphene nano-sheets by pyridine group and characterized by transmission electron microscopy (TEM), thermal analysis (TG/DTA), elemental analysis (CHN) and infrared spectroscopy (IR). The application of this sorbent in determination of lead ions in environmental samples was investigated. Some parameters such as pH and time on adsorption process we Read More

Enantioseparation of 2-chloromandelic acid enantiomers by ligand exchange chromatography was successfully carried out using chiral ionic liquids (CILs) containing imidazolium cation and L-Proline anion as chiral selectors. The main factors influencing resolution, such as alkyl chain length of CILs, concentrations of Cu2+ and CILs, pH of the mobile phase and temperature, were investigated. To better understand the enantiose Read More

A simple, novel and sensitive assay method was developed and validated for the estimation of febuxostat, an anti-gout agent, in human plasma using high-performance liquid chromatography coupled to tandem mass spectrometry. The bioanalytical method is involved in liquid–liquid extraction of febuxostat and rosiglitazone (internal standard: IS) using micro volume (100 μL) human plasma and quantitation by triple q Read More

Propolis – in the form of alcoholic extract – is one of the most produced and commercialized bee products in the world due to its many pharmacological properties hence several chemical compositions which vary according to their producing regions, botanical source, type of bee, climate amongst other factors are there. In this manner, this study has the objective of finding a relation among the Brazilian commerci Read More

In this study, the simultaneous determination of verapamil hydrochloride, gliclazide and simvastatin in pharmaceuticals by chemometric approaches using UV spectrophotometry has been reported. Spectra of verapamil hydrochloride, gliclazide and simvastatin were recorded at several concentrations within their linear ranges and were used to compute the calibration mixture between wavelength range of 200 a Read More

In this work, a new version of RAFA was developed for simultaneous determination of the stepwise dissociation constants along with concentration of multiprotic acids based on pH gradual change-UV spectral data. The main aim of this study was to introduce an improved version of the model based RAFA for quantification of analytes and also calculation of model parameters without knowing the pure spectra. The proposed me Read More

A stability-indicating reversed-phase high-performance liquid chromatography (RP-HPLC) method has been developed which can separate and accurately quantitate Mebeverine hydrochloride (MEB) and Chlordiazepoxide (CPZ) in commercial tablets. The method has shown adequate separation for MEB and CPZ from their degradation products and main impurities of CPZ whether in pure forms or in commercial tablet Read More

Resolution of complex binary mixtures of Ethinylestradiol (ST) and Levonorgestrel (LEV) was successfully achieved with minimum sample pre-treatment and without analyte separation. The work is based on the radial basis functions- partial least squares (RBF-PLS) analysis of UV spectral data. For calibration and external test sets, binary mixtures were rationally designed. The results for modeling and subsequent predictio Read More

In this study emulsification based liquid microextraction (EBLME) was developed for preconcentration of Cu(II) using a redesigned dispersive liquid - liquid microextraction (DLLME). The procedure is based on an organic extraction solvent and aqueous solution of surfactant system where a mixture contains appropriate amounts of the extraction solvent (25.6 μg mL-1 dithizone chloroformic solution) and aqueous solution of s Read More

In this work solid phase extraction had been implemented with fiber optic-linear array detection spectrometry and partial least squares (PLS) multivariate calibration approach for simultaneous determination of ultra trace amounts of metals with complexes which have overlapping spectra. An octadecyl silica membrane disk modified with N-benzoyl-Nphenylhydroxylamine (BPHA) in combination with partial least squares regr Read More

Nucleic acid-based biosensors are typically used to detect DNA or RNA fragments of genetic importance. However, nucleic acids can also serve as binding partners for other molecules, including metal ions. This binding occurs through electrostatic interactions between metal cations and negatively charged DNA strands and through the specific binding of metal cations by donor atoms from the phosphate groups and nucle Read More

Nitric oxide (NO), a reactive free radical, is an important messenger molecule in biological cells. It plays a critical role in regulating vascular tone, host immunity, neurotransmission, nutrient metabolism and the whole-body homeostasis. NO is metabolized into various products, including plentiful nitrite and nitrate in the circulatory and excretory in vivo, others such as peroxynitrite, nitronium ions, nitroxide ions, and S-nitr Read More