Showing papers in "Analytica Chimica Acta in 1981"

TL;DR: In this paper, the response of 10 simple carbohydrates was investigated voltammetrically at platinum electrodes in 0.10 M sodium hydroxide by application of a conventional linear sweep waveform and a triple-pulse waveform.

TL;DR: In this article, a highly selective method is presented for the detection of organic "gunshot residue" on the hand of individuals who have discharged a weapon, and the detection limits at S/N = 3 are of the order of 0.5, 1, 2, and 0.3 picomol for nitro aromatic, nitramine and nitrate ester explosive compounds, and diphenylamines, respectively.

TL;DR: The fluorigenic reaction of proline with 7-fluoro-4-nitrobenzo-2-oxa-l,3-diazole (NBD-F) is superior, in terms of reactivity and fluorescence yield, to the reactions with the analogous 7-chloro and 7-bromo derivatives as mentioned in this paper.

TL;DR: An electrically neutral hydrogen ion-selective carrier, tri-n-dodecylamine, was used as the active component for liquid-membrane electrodes as mentioned in this paper.

TL;DR: In this article, the frequency change of a piezoelectric quartz crystal on electrodeposition on the electrode of the crystal was determined in situ by determining the silver in solution.

TL;DR: In this paper, the potentialities of zone-sampling processes are discussed, and the main factors involved are investigated by spectrophotometric measurements, and a simple system which provides automatic dilution, allows analysis of 120 samples per hour, although the required sample dispersion factor was 0.0076; the results agreed with those obtained by conventional a.a.s.

TL;DR: The effect of naturally occurring organic materials on the coprecipitation behavior of trivalent chromium was studied to estimate the relative abundance of organic-bound chromium in sea water as mentioned in this paper.

TL;DR: In this paper, the role of manganese oxides in the oxidation process of Cr(III) to Cr(VI) in sea water was investigated and it was shown that the theoretical redox equilibrium controlled only by dissolved oxygen is not always attained in practice.

TL;DR: In this paper, a semi-quantitative description of the dispersion process in open tubes is presented for conditions prevailing in flow injection analysis, and it is shown that uncoupling the two functions of the tube (i.e., mixing and creating a residence time) can be accomplished by making use of a simple mixing device followed by a tube packed with glass beads of relatively large diameter (up to 70% of the i.b.d.

TL;DR: Animated microparticulate silica gel was derivatized with the fluorescent tag, dansyl chloride, to produce a chemically modified silica surface that could be examined by fluorescence spectroscopy.

TL;DR: In this paper, a triple-pulse waveform was used for the anodic detection of methanol, ethanol, and ethylene glycol in a flow-injection system.

TL;DR: Selective, multipurpose electrodes have been developed from the previously described glucose electrode based on amperometric detection of hydrogen peroxide, and a comparative study of membranes produced by random co-immobilization, stacking of membranes and asymmetric coupling improves the electrode performances.

TL;DR: In this paper, the authors exploit the reproducible concentration gradients formed between an injected sample zone and the carrier stream in flow injection analysis for titrations based on measuring the time span between points of identical gradient dispersion.

TL;DR: In this article, the effects of four washing procedures on the concentrations of manganese, iron, copper, zinc and cadmium were investigated for three pooled samples of human head hair.

TL;DR: In this article, the spectral interferences of phosphorus species originating from the thermal decomposition of calcium phosphate on Sb, As, Se and Te resonance lines, and the influence of increasing amounts of Ce, Ni, W, Pd, Pt, Zr and other elements on non-correctable signals generated by calcium phosphate and on selenium and phosphorus sensitivity have been studied.

TL;DR: It is suggested that some methods previously identified as continuous-flow titrations are most accurately identified as variable-time kinetic methods, and it is shown that this semantic differentiation can provide improved insight into the methods and expand the scope of the methods by suggesting new experimental approaches with potential advantages relative to previously described procedures.

TL;DR: Synchronous fluorescence and the room-temperature phosphorescence methods were used to determine selected polynuclar aromatic hydrocarbons in a coal liquid (solvent-refined coal) product without a preseparation step.

TL;DR: In this paper, the interference from selenium (IV) on the determination of arsenic (III) and -V) by hydride-generation atomic absorption spectrometry is removed if copper is added to the sample solution.

TL;DR: In this article, the solution conditions and other parameters affecting the ammonium pyrrolidine-dithiocarbamate-methyl isobutyl ketone extraction system for graphite-furnace atomic absorption spectrometric determination of As(III), As(V), Sb(III) and Se(IV) were studied in detail.

TL;DR: In this paper, a method for the determination of chromium(III), chromium (VI) and organically bound chromium in sea water is reported, and it is confirmed that sea water contains about 9 × 10-9 M dissolved chromium.

TL;DR: In this paper, a potentiometric membrane electrode with selective response to L-glutamate over the 2 × 10 -4 -1.3 × 10 −2 M concentration range is constructed by immobilizing slices of yellow squash tissue at a CO 2 gas sensor.

TL;DR: In this paper, a number of synthetic aspects of silica-bound complexing agents are considered, and modifications of the procedure for amidization of bound amines and of the diazotizationcoupling sequence are discussed.

TL;DR: In this article, the characteristic absorption bands of lignin in the ultraviolet range of the spectrum were used for the determination of residual free lignins in broth cultures, and the effects of medium composition, pH, biomass, metabolite production and some lignini-related aromatic compounds were reported.

TL;DR: In this paper, a flow injection system with inductively-coupled argon plasma atomic emission spectromeiry is proposed, which provides nearly zero sample dispersion and so the inherent sensitivity of the spectrometric method is preserved.

TL;DR: In this paper, the authors compared the dispersion of three different types of flow injection methods: a straight tube, a helically coiled tube and a new single bead string reactor.

TL;DR: In this paper, the effect of the ratio of inner container surface to sample volume on the sorption loss of 41 elements from aqueous solutions under different experimental conditions was studied.

TL;DR: In this paper, metal dithiocarbamate extractions with three different organic solvents (chloroform, freon and 4-methylpentan-2-one) followed by back-extraction with nitric acid are described.

TL;DR: The data show that the variable-time kinetic model is superior to the titration models previously utilized to describe these flow systems and is useful in predicting performance characteristics for a variety of conditions and experimental approaches.

TL;DR: In this article, cyclic voltammetry and potentiostatic coulometry were used to study the electrochemical oxidation of thiourea in aqueous solutions of nitric acid, ammonium nitrate and ammonium hydroxide and in acetonitrile.

TL;DR: A flow injection system for glucose and urea determination uses immobilized glucose oxidase in a reactor designed to give 100% substrate conversion and the effects of the dialyser, enzyme reactors and detectors on dispersion are evaluated.