In this review the history of chemistry and specifically the history and the significant steps of the evolution of analytical chemistry are presented. In chronological time spans, covering the ancient world, the middle ages, the period of the 19th century, and the three evolutional periods, from the verge of the 19th century to contemporary times, it is given information for the progress of chemistry and analytical chemistry. During this period, analytical chemistry moved gradually from its pure empirical nature to more rational scientific activities, transforming itself to an autonomous branch of chemistry and a separate discipline.
View Article and Find Full Text PDFThis paper describes the monitoring of 16 polynuclear aromatic hydrocarbons (PAH) in the suspended particulate matter in the area of Ioannina. A total of 244 samples were collected from five locations throughout the city. These samples were analyzed in order to acquire a complete picture of the PAH abundance and distribution above the city of Ioannina.
View Article and Find Full Text PDFThe development of 1-(2-pyridylazo)-2-naphthol (PAN)-modified polymeric membranes for the effective batch pre-concentration and determination of zinc traces with flame atomic absorption spectrometry (FAAS) is described. The method is based on the chemical bonding of the metal species with a suitable ligand, which has been immobilized into a water-insoluble cellulose acetate (CA) membrane followed by simple rinsing of the chelating agent-metal complex with an acidified methanolic solution. The latter is directly aspirated to the nebulizer of a FAA spectrophotometer without any other treatment.
View Article and Find Full Text PDFThis article describes an analytical method for the determination of magnesium taking advantage of the cloud point phenomenon employing a suitable chelating agent (chloranilate) for Mg analysis. The method encompasses pre-concentration of the metal chelate followed by flame atomic absorption spectrometry (FAAS) analysis. The chelating agent chosen for this task is a newly synthesised salt of chloranilic acid, trizma-chloranilate, which reacts with Mg but at the same time has a very low affinity for other metallic cations like silicon, aluminium and sodium, which interfere with the determination of Mg in FAAS.
View Article and Find Full Text PDFThis article investigates the controls on sediment phosphorus (P) speciation dynamics as a function of its fractionation into chemically defined operational pools along a river continuum. A total of 27 variables were analyzed in bed sediment samples collected for one year from six sampling points, along a 75km river continuum (Louros River, NW Greece). Multivariate explanatory analysis of the complex experimental data matrix was performed in order to unravel the spatial pattern of P speciation.
View Article and Find Full Text PDFThe first amperometric biosensing method for the determination of L-fucose is described. L-Fucose is the objective of much current research, as it is considered as a potential marker for various pathologic disorders. Recombinant L-fucose dehydrogenase, having as cofactor beta-nicotinamide adenine dinucleotide phosphate (NAD+P), was cross-linked in a water-soluble photosensitive polymer matrix, that is, polyvinyl alcohol (PVA) modified with styrylpyridinium (SbQ), in the presence of BSA and glutaraldehyde.
View Article and Find Full Text PDFThe phase separation of lamellar vesicles of anionic surfactants in aqueous solutions and its application as a novel liquid coacervate extraction procedure was examined. Solutions of lauric acid sodium salt separate into two phases in the presence of alkaline earth metals and a water miscible cosurfactant. It is proven that the surfactant phase is built of a perplexed network of multilamellar vesicles consisting of densely packed bilayers.
View Article and Find Full Text PDFIn an effort to monitor orthophosphate in natural waters and wastewater in the Ipirous region (Greece), an analytical methodology was established owing to the need for interference-free determination at the low mg/l levels. The method applied for the determination of orthophosphate is based on its reaction with molybdate towards a yellow heteropoly acid complex, which is electrically balanced with a cationic surfactant (cetylatrimethylammonium bromide) towards a complex non-polar derivative. This derivative is conveniently solubilized in the micelles of a non-ionic surfactant under mild conditions and measured spectrophotometrically at 370 nm after its uptake with a sulfuric acid-methanol solution.
View Article and Find Full Text PDFThe first amperometric flow analyzer, based on the biosensor concept, capable of determining total glucosinolates in real samples, is described. Myrosinase was immobilized on aminopropyl-modified controlled pore glass, which was then used for the construction of a packed-bed reactor. Myrosinase catalyzes the hydrolysis of glucosinolates (sinigrin) to glucose (among the other products), which is then oxidized by the action of glucose oxidase to produce hydrogen peroxide.
View Article and Find Full Text PDFA cloud point extraction-preconcentration methodology for the speciation analysis of free and organically complexed metal species in natural waters is presented. The method is based on the neutralization of the electrostatic charge of the humate-metal complexes with a positively charged surfactant in a high ionic strength solution environment. The resulting complexes are conveniently solubilized in the micelles of a non-ionic surfactant medium and are thus separated from the bulk aqueous phase.
View Article and Find Full Text PDFA method has been developed for the simultaneous determination of traces of Fe(III) and Fe(II) in water by on-line coupling of spectrophotometry with flame atomic absorption spectrometry (FAAS). The method involves cloud-point extraction (CPE) of both species with ammonium pyrrolidinecarbodithioate (APDC) under standard conditions, which facilitates the in situ complexation and extraction of both species. Differentiation of the oxidation states of iron is achieved by using mathematical equations to overcome the interference of Fe(III) in the spectrophotometric determination of Fe(II) when they are both present in the same solution.
View Article and Find Full Text PDFThe first enzyme-based biosensors capable of determining glycolic acid in various complex matrixes, such as cosmetics, instant coffee, and urine, are presented in this paper. Two separate designs, both based on a three-membrane configuration consisting of an inner cellulose acetate membrane (CA) and an outer polycarbonate membrane (PC), which sandwich a membrane bearing the biomolecule(s), are proposed. Glycolate oxidase was immobilized onto a modified polyethersulfonate membrane by means of chemical bonding, and glycolate oxidase/catalase enzyme mixture was immobilized into a mixed-ester cellulose acetate membrane through physical adsorption.
View Article and Find Full Text PDF