Showing papers in "Analytica Chimica Acta in 1982"

TL;DR: In this article, a graph of the ratio between the free and bound metal concentration vs. the free metal concentration is used for interpretation of direct titration of natural waters with trace metals.

TL;DR: In this article, the authors present a two-parameter Debye-Huckel model for the calculation of mean activity coefficients, which is the most trustworthy and comprehensive method.

TL;DR: In this paper, a piezoelectric quartz crystal oscillates in organic liquids, and the frequency change depends on the density (d) and viscosity (η) according to ΔF = ad 1/2 + bη 1 /2 − c, where a, b and c are constants depending on the crystal.

TL;DR: In this article, the characteristics of ideal mediators are discussed and structural information on previously reported mediator compounds is provided, and a current survey of compounds having suitable redox mediation characteristics is provided.

TL;DR: On the basis of an example of differentiation between EU thyroid function and HYPER thyroid function, it is shown that alternative votes can give rise to better classification results than the majority vote.

TL;DR: In this article, the dithiocarbamate complexes of the metals are extracted into Freon-TF and back-extracted into dilute nitric acid solution, which gives complete separation from the matrix irrespective of salinity.

TL;DR: In this paper, the key set of typical rows (or typical columns) used to reproduce a data matrix, are obtained by finding the set of rows or set of columns most orthogonal to each other.

TL;DR: In this paper, a critical evaluation of adsorptive accumulation in stripping analysis, with differential pulse polarography for the measurement step, is described, and generally applicable conditions for this method are given.

TL;DR: In this paper, the mechanism of electrogenerated chemiluminescence of luminol in aqueous alkaline solution based on the rotating ring-disc electrode system is discussed.

TL;DR: In this article, all published procedures for multi-element preconcentration of trace elements, prior to x-ray fluorescence analysis of water, are reviewed and evaluated, and most of them apply to the determination of single elements in water.

TL;DR: More than 50 nitro-PAH have been tentatively identified in an extract of diesel-exhaust particulates as mentioned in this paper, based on high-resolution mass spectrometry of directly mutagenic fractions derived from sequential fractionation of the extract by both low- and highresolution liquid chromatography.

TL;DR: An implementation of the k NN classification method of Loftsgaarden and Quesenberry is discussed in this article, which is a theoretically valid alternative for probabilistic pattern recognition by means of the Bayes equation.

TL;DR: In this article, a range of model compounds were studied to test the effect of complexing agents on the adsorption of copper, lead, cadmium and zinc by Chelex-100 resin, oxine porous glass, thiol porous glass and thiol resin, from seawater and distilled water.

TL;DR: In this article, the authors reviewed and correlated results obtained from tests conducted on the Shroud of Turin during the October 1978 investigation and concluded that the image is the result of some cellulose oxidation-dehydration reaction rather than an applied pigment.

TL;DR: In this paper, the Modified Simplex method and the Controlled Weighted Centroid method with minor but essential alterations are evaluated for four test functions and an attempt to design a combination of these two methods is discussed.

TL;DR: The feasibility of selecting reproducibly a suitable element of the dispersed sample zone in a flow injection system is exploited for stopped-flow measurement of the enzymatic activity of lactate dehydrogenase as discussed by the authors.

TL;DR: In this article, a pre-valve in-invalve reduction technique is used to reduce nitrate to nitrite by using the prevalve before the sampling system, which is suitable for the simultaneous determination of nitrate and nitrite at a sampling rate of up to 72 determinations per hour with coefficients of variation better than 1.96% for Nitrate and 0.83% for nitrite.

TL;DR: The lower limit of linear response in flow-injection systems employing membrane and second-kind ion-selective electrodes as detectors depends on the dispersion in the system and is usually much worse than in batch measurements as mentioned in this paper.

TL;DR: In this paper, eight Nalkyl-N-V-sulphopropyl-m-anisidine derivatives have been synthesized and assessed as water-soluble hydrogen donors for the spectrophotometric determination of hydrogen peroxide in the presence of peroxidase.

TL;DR: The sensor system for total cholesterol was assembled with the immobilized enzyme reactor, a hydrogen peroxide electrode and a peristaltic pump, and was used for 300 assays without loss of enzymatic activity.

TL;DR: It was established that the interface at a PVC membrane containing cardiolipin, lecithin and cholesterol with electrolyte solutions is non-polarized, and it is suggested that the observed changes of potential are due to the changes of exchange current densities of individual ions which participate in the ion-exchange process and establish a mixed potential at that interface.

TL;DR: The use and characteristics of a nickel oxide electrode as a detector for amines in a flow injection system are described in this paper, where anodic electrode reaction mechanism involves a higher oxidation state of nickel maintained by the applied potential (+0.49 V vs. SCE).

TL;DR: In this paper, hydrogen peroxide is determined by a chemiluminescence method with a reagent containing 100 μM luminol and 3 μM microperoxidase at pH 10 (carbonate buffer).

TL;DR: The metal uptake behavior of these amine- and dithiocarbamate-cellulose derivatives were compared for Cu(II), Cd(II) and Pb(II).

TL;DR: In this paper, the molar ratio of the stabilizer to sulfite as well as the concentration of sulfite was found to be sufficient for stabilizing a sulfite solution for at least 72 hours.

TL;DR: In this article, the performance of calcium ion-selective microelectrodes based on a neutral carrier for extra and intra-cellular measurements of free Ca 2+ ions is assessed.

TL;DR: In this paper, the amperometric behavior of a copper electrode towards amino acids is studied by means of a rotating disc electrode and a theoretical model describing the anodic background current in buffer solution and the increase of the current caused by amino acids are checked experimentally.

TL;DR: An improved, automated method for the determination of arsenic and antimony in geological materials is described in this paper, where the material is decomposed in a heated quartz tube in the optical path of an atomic absorption spectrometer.

TL;DR: In this paper, seven methods for preconcentration of the elements Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Ag, Cd, Sb, Hg, Tl, and Pb in trace quantities from water have been evaluated.